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FINAL PROJECT REPORT

1. Ecowatt FINAL PROJECT REPORT Calvin College ENGR 340 May 7 2008 Team 10 Members From Left Chris Michaels EE Jared Huffman ME EE Brianna Bultema ChE and Achyut Shrestha EE Ecowatt 2008 Calvin College Ecowatt and Achyut Shrestha Chris Michaels Brianna Bultema Jared Huffman Ecowatt Table of Contents 1 Executive Summary iere e vr RR en e APP Hg UR lekeareal arier 8 Mise io MERE ao m T E MM 9 S PORS ETEN edda dd odkad 9 3d F RT SFs roi Az 9 32 Project ODJECINEG m 10 3 3 Project Requirement and Criteria sluha koed dA LEO 11 34 MONTE 11 Favre 12 LEE uisi e een 12 4 2 MFC System Monitor zz iier eren nente tna oa one ERR esa orae a eo pense adnan SKE ESKS 12 43 Regulator Circuit Design LL eniro tde prius e th nong EP aoi lid daw d Ue ida 13 44 Feeding Process eko Gia Ua kr dadza 13 5 Team Pils awa DE ud rd a r ac taz 14 5 1 Christian Perspective on the Project z soka dle me m te ajka 14 5 Method of ADBIOSCI SE ME EE A 14 5 2 1 PRESS Clin Gen R O O od 14 5 2 2 Desig p 14 5 2 3 liriplerientatlofi EEE c 15 5 3 Safety and Environmental Impact rrrreronnrrvnrannrrrnnsrennrnenrennrrnnssnnrrnnssnennrnessennrnnnssnnnnenee 15 5 3 1 Electrical IMAC EE dokach 16 5 3 2 Material IMBREL zda bi dada ARE GE Bao ada cb 16 5 3 3 chemical Fre ziska AGA AE 16 b Proposed Sato Ri codzi duo ako Zadat Gun eo dua da la no da rada ad 18 6 1 Project MANAGOMeE ssa aaa
2. buttons PINB 6 PINB MASK buttons PINE amp PINE MASK Output virtual keys if buttons amp 1 lt lt BUTTON A key KEY PLUS else if buttons 6 1 lt lt BUTTON B key KEY MINUS else if buttons 6 1 lt lt BUTTON C key KEY PREV else if buttons 6 1 lt lt BUTTON D key KEY NEXT else if buttons amp 1 lt lt BUTTON 0 key KEY ENTER else key KEY NULL if key KEY NULL if gButtonTimeout gButtonTimeout is set in the LCD SOF interrupt in LCD driver c if KEY VALID KEY key Store key in global key buffer KEY VALID TRUE gButtonTimeout FALSE EIFR 1 lt lt PCIF1 1 lt lt PCIFO0 Delete pin change interrupt flags gPowerSaveTimer 0 Reset the Auto Power Down timer kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk ck e ck ck kk kk ck kk ck AA KK A AAA AKA KK AKA A KA ko ko e hh A Function name getkey Returns The valid key Parameters None Purpose Get the valid key 108 Ck Ck ck ck ck ckck AK AA AA KA KK A ZA A KA KKK AKA AZ kck kk kk ck kk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk char getkey void char k cli mt _ disable interrupt LE KEY VALID Check for unread key in buffer k KEY KEY VALID FALSE se else k KEY NULL No key stroke available sei mt enable interrupt return k ORR kk kk kk kk kk Kk kok kk kk k kok
3. Current on the inmA MAX1524 lin lout IGND IFB ISET ISHDN EXT Icc 312 187 0 0 0 250 0 250 500 437 0 0 0 500 0 500 750 625 0 187 0 750 0 750 1000 1120 0 437 0 1000 937 1000 1250 2680 0 1310 0 1120 1120 1120 1500 4310 0 2500 0 1250 1250 1250 1750 7930 0 6300 0 1370 1370 1370 1870 7930 0 7000 0 1370 1430 1370 2060 7930 0 4800 0 1370 1370 1370 2500 7930 0 5830 0 1430 1250 1500 2500 7930 0 7680 0 1500 1500 1500 2930 4750 0 2000 0 1060 1060 1060 Resistor Capacitor Currents Currents IR1 IR2 IR3 Ica Ic2 Ica ICFF 187 0 250 250 187 250 187 437 125 500 500 437 500 437 625 187 750 750 625 750 625 1200 437 1000 1000 1200 1000 1200 2680 1250 1250 1250 2680 1120 2680 4430 2560 1560 1500 4370 1250 2000 7930 6000 2060 2180 7930 1370 4680 7930 7060 2060 2250 7930 1370 7930 7930 4750 2120 2180 7930 1370 7930 5120 5930 2250 2370 7930 1870 7930 7930 7930 2750 2680 6180 1620 7930 4810 2120 3000 2930 4870 1060 4810 Ecowatt by Inductor MOSFET Current Currents Diode Currents IL1 lo1s lo1G lo1D ID1in ID10ut 250 0 0 250 250 187 500 0 0 500 500 437 750 0 0 750 750 625 1000 0 1000 1250 1250 1120 1250 0 1120 2870 2750 2620 1560 0 1250 4620 4680 4250 2120 0 1370 5750 5500 5060 2000 0 1430 7930 7930 5310 2180 0 1430 7930 7930 7930 2370 0 2600 6810 6810 7930 2750 0 1120 1120 7930 7930 3000 0 1060 3930 4930 4810 Resistance Ri R2 R3 RL 193770 64470 10 07 988 193770 64470 10 07 988 193770 644
4. TARGET cof extcoff TARGET elf 121 Gecho Gecho S TARGET cof S COFFCONVERT O coff ext avr TARGET cof MSG EXTENDED COFF Program the device program TARGET hex TARGET eep AVRDUDE AVRDUDE FLAGS AVRDUDE WRITE FLASH AVRDUDE WRITE EEPROM Create final output files hex eep from ELF output file hex elf echo echo MSG FLASH 0 OBJCOPY 0 FORMAT R eeprom lt S eep elf echo echo MSG EEPROM 6 OBJCOPY j eeprom set section flags eeprom alloc load X change section lma eeprom 0 O S FORMAT lt S Create extended listing file from ELF output file 1ss elf echo echo MSG EXTENDED LISTING Se OBJDUMP h S lt gt Create a symbol table from ELF output file sym elf Gecho echo MSG SYMBOL TABLE avr nm n Q Link create ELF output file from object files SECONDARY TARGET elf PRECIOUS OBJ elf OBJ Gecho echo MSG LINKING 6 CC ALL CFLAGS output 80 S LDFLAGS OBJ Compil creat Source files object files from C Ecowatt 9 0 c Gecho echo MSG COMPILING lt S CC o ALL CFLAGS lt o Compil create assembler files from C source files T NG 5 CC 8 ALL CFLAGS lt o E Assembl creat object files f
5. Global functions kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk void LCD Init void void LCD WriteDigit char digit void LCD AllSegments char show input char extern uint8 t gSECOND extern uint8 t gMINUTE extern uint8 t gHOUR extern uint8 t gDAY extern uint8 t gMONTH mtE extern unsigned int gYEAR Function declarations void RTC init void initialize the Timer Counter 2 in asynchron operation define CLOCK 24 1 define CLOCK 12 0 Typedef for Timer callback function typedef void TIMER CALLBACK FUNC void define TIMERO NUM CALLBACKS 4 define TIMERO NUM COUNTDOWNTIMERS 4 void Timer0 Init void BOOL Timer0 RegisterCallbackFunction TIMER C ALLBACK FUNC pFunc BOOL Timer0 RemoveCallbackFunction TIMER CAL LBACK FUNC pFunc mt char Timer0 AllocateCountdownTimer char Timer0 AllocateCountdownTimer void char Timer0 GetCountdownTimer char timer void Timer0 SetCountdownTimer char timer char value void Timer0 ReleaseCountdownTimer char timer makefile 118 WinAVR Sample makefile written by Eric B Weddington J rg Wunsch et al Released to the Public Domain Please read the make user manual Additional material for this makefile was submitted by Tim Henigan Peter Fleury Reiner Patommel Sander Pool Frederik Rouleau Markus Pfaff On command line make a
6. Table 7 Monitor Voltage Level Display Vin Display text gt 3 0V Battery Good 2 7V 3 0V Battery OK 2 3V 2 7V Battery Low No output lt 2 3V Battery Flat Feed now The figure to the void Power check void int voltage 0 right shows how the voltage coming out of the MFC compares to the ADC init 1 voltage ADC read appropriate output PGM P statetext information to the user E if voltage gt PUR MAX V battery is really really good statetext PSTR Batt Full jelse if voltage gt PUR GOOD V battery is freshly charged statetext PSTR Batt Good else if voltage gt PUR LOW V normaloperation mode statetext PSTR Batt OK else if voltage PUR MIN V only 12 left Statetext PSTR Batt Low jelse statetext PSTR Batt Flat j LCD UpdateRequired TRUE 0 LCD_puts_f statetext 1 statetext NULL Figure 31 MFC Power Check Function Ecowatt Temperature The temperature sensor also connects to a 10 bit ADC The temperature reading converts to equivalent voltage reading Then the optimum range for temperature displays as shown below Table 8 Monitor Temperature Level Display Temperature Display text 20 C 35 C Optimum temperature Rest Temperature out of range battery performance low The following function Figure 32 Temperature Check Function reads the temperature and deter
7. z o o Power In W Figure 38 Input Power vs Output Power Efficiency with Variable Input Voltage 0 25 0 2 lt IEEE 0 0 5 1 1 5 2 2 5 3 3 5 Efficiency Input Voltage V Figure 39 Efficiency with Variable Input Voltage Notably the power curve for efficiency follows an almost bell shaped curve meaning that the circuit has an optimum efficiency around 1 75V Since the placement of the peak in efficiency is lower than expected doing the changes recommended in the next section will change this measurement Ecowatt Load Resistance vs Output Current A Output Current in A e 0 1 2 3 4 5 6 7 8 9 Load Resistance in Ohms Figure 40 Load Resistance vs Output Current Seeing how the output current reacts to the load resistance further investigation is necessary as to why this occurs Performance Currently the voltage regulator refuses to give the desired output of 5V The regulator regulates to a voltage of 7 93V instead Research is ongoing as to the reason why Several reasons for why the regulator will not behave as desired have come to attention One of these reasons includes the fact that a miscalculation occurred resulting in the inductor being too small by one degree of magnitude Assistance from Maxim s support team helped to point out this error In addition the resulting current from going through the inductor is too small
8. Vep 1367 V DEAL 3953x 107 H xg FB FB LIDEAL LIDEAL 5UDEAL 1976x10 H Switching Frequency 2 a M Pro Vout VD R out D in LR lead gt BL SWITCHING hr 73 Vin tonmin Vp T Vout Y LIGHTLOAD 7 tonmin V V out 0 18 Hpadmax Output Capacitor Selection Ce load tonmin ODS Resistance onthe Capacitor L lioadrax FSFyoutmint Z outmin in 3 VFB ESReoutmin 60 10 Lr Feedforward Capacitor 6 1 1 Cpp 310 ment rez MOSFET Selection IGATE Cz WITCHIN Currenton the Diode IDIODE but Ipeak Ecowatt Noadmax tss outmax Nu 3 ESR outmini 27 me VRIPPLE 0 3IpE KESEcoutin VRIPPLE 0 023V 1 CFB 35 CFF Feedback Capacitor Ripple V CFF ppl p RIPPLEC 5 Cpp Rippkgg 0022V Note Ripplegg should be 25mV to 40mV Gannotget calculationte work out due to the limits of the function Ecowatt Circuit Diagrams Below Error Reference source not found is a diagram of the MAX1524 circuit that has become the voltage regulator for the Biobattery Although the values for L1 R1 R2 Cre and C2 are different to give the regulator the ability to take a lower input voltage the rest of the topology remains the same One further note is that the pin marked SHDN needs a connection to Vcc INPUT 33V 10 Figure 22 Regulator Circuit Diagram Ecowatt 6 4 9 USB Power Switch The MAX1607 IC generates the
9. string to the LCD Ck ck ck ck ck KAZ AK AA AA KA KK A ZA A KA KAZ AKA A kckckck kk kk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk void LCD puts char scrollmode pStr char uint8 t i char i while gLCD Update Required Wait for access to buffer for i 0 TEXTBUFFER SIZE i pStr i amp amp i lt gTextBuffer i pStr i gTextBuffer i N0 if i gt 6 109 gScrollMode 1 Scroll if text is longer than display size gScroll 0 gLCD Start Scroll Timer 3 Start up delay before scrolling the text else gScrollMode 0 gScroll 0 gLCD Update Required 1 fk kk kk kk kk kok k kok ee kok k kok hh kk ek kk kkk ok kk kk dk hg KA KA A K AA KAZ A AXA K KA ZAK o KA kck hh Function name CHAR2BCD2 Returns Binary coded decimal value of the input 2 digits Parameters Value between 0 99 to be encoded into BCD Purpose Convert a character into a BCD encoded character The input must be in the range 0 to 99 The result is byte where the high and low nibbles cj contain the tens and ones of the input ck ck ck ck ok ck ck ck ck e o kk kk ck ok ck ck 3 e hh hh hh ko ko ko k ok kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk char CHAR2BCD2 char input char high 0 while input gt 10 Count tens high input 10 return high lt lt 4 input Add ones and return answer kk kk KKK KK
10. 100 Store the low byte Temp CHAR2BCD2 VoltageHB Convert from char to bin TL Temp 6 OxOF 0 Temp CHAR2BCD2 VoltagelB Convert from char to bin VH Temp gt gt 4 0 VL Temp 6 OxOF 0 LCD putc 0 LCD putc l LCD putc 2 TL LCD putc 3 v LCD putc 4 VH LCD putc 5 VL LCD putc 6 N0 kkkkkkkkkkkkkkkkkkkkkkkkkkkkk Function name Power check xi Returns nothing di Parameters none i Purpose display power level kkkkkkkkkkkkkkkkkkkkkkkkkkkkkk void Power check void int voltage 0 ADC init 1 voltage ADC read PGM P statetext if voltage gt PWR MAX V battery is really really good statetext PSTR Batt Full Ecowatt Jelse if voltage gt PWR GOOD V battery is freshly charged statetext PSTR Batt Good Jelse if voltage gt PWR LOW V normal operation mode statetext PSTR Batt GK Jelse if voltage gt PWR MIN V only 12 left statetext PSTR Batt Low Jelse statetext PSTR Batt Flat LCD UpdateRequired TRUE 0 LCD puts f statetext 1 statetext NULL char Temp check void int temperature 0 char temp_error F ADC_init 0 temperature ADC read if temperature gt 574 B temperature lt 396 temp error T else temp error F return temp er
11. 1Mhz 103 CLKPR 1 lt lt CLKPS1 1 lt lt CLKPS0 TIMSK2 0 disable OCIE2A and TOIE2 ASSR 1 lt lt AS2 select asynchronous operation of timer2 32 768kHz OCR2A 200 set timer2 compare value TIMSKO 0 delete any interrupt sources TCCR1B 1 CS10 start timerl with no prescaling TCCR2A 1 CS20 start timer2 with no prescaling while ASSR amp 0x01 ASSR amp 0x04 wait for TCN2UB and TCR2UB to be cleared Delay 1000 wait for external crystal to stabilise while calibrate cli mt _ disable interrupt disable global interrupt TIFR1 OxFF delete TIFR1 flags TIFR2 OxFF delete TIFR2 flags TCNTIH 0 clear timerl counter TCNT1L 0 TCNT2 0 clear timer2 counter while TIFR2 66 1 lt lt OCF2A wait for timer2 compareflag TCCR1B 0 stop timerl sei enable interrupt enable global interrupt if TIFR1 amp amp 1 lt lt TOV1 temp OxFFFF f timerl overflows set the temp to OxFFFF else read counter value tempL TCNT1L temp TCNT1H out the timerl Ecowatt temp temp lt lt 8 temp templ if temp gt 6250 OSCCAL oscillator runs to fast OSCCAL the internRC decrease the else if temp 6120 OSCCAL the internRC oscillator runs too slow increase the OSCCAL else calibrate
12. ADC2Temp temp val Delay 3000 LCD Clear LCD UpdateRequired TRUE 0 for temp_err Temp check if temp err T if PowerSaveTimeout gPowerSaveTimer break LCD puts Temp out of range 1 Delay 5000 else break LCD puts Optimum Temp 1 Delay 5000 LCD Clear LCD UpdateRequired TRUE 0 for Power check Delay 4000 if gPowerSaveTimer gt PowerSaveTimeout break gPowerSaveTimer 0 102 LCD puts f PSTR bye 1 Delay 3000 SMCR 2 SMO 1 lt lt SE Enable Power down mode asm volatile sleep if PINB amp 0x40 press UP to wake from SLEEP PowerSave FALSE for i 0 i lt 20 i set all LCD segment register to the variable ucSegments amp pLCDREG test i 0x00 sbi LCDCRA Ty enable LCD input getkey Read buttons gPowerSaveTimer 0 reset seconds until sleep timer SMCR 0 Just woke disable sleep End Main loop return 0 kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk ck ck ck kk kk ck kk ck KA KK A AAA AKA KK AKA k KA e ko e w w Function name Initialization Returns None Parameters None Purpose Initializate the different modules Ck ck ck ck ck ckck AK AA ZA KA KK A KZ A A ZA KAZ AKA A kckckck kk ck kk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk void In
13. Define all listing files LST ASRC S lst SRC c lst Combine all optional flags Add target processor to flags ALL CFLAGS mmcu MCU I CFLAGS ALL ASFLAGS mmcu MCU I x assembler with cpp ASFLAGS necessary flags and Default target all begin gecversion TARGET elf TARGET eep sizebefore TARGET hex Ecowatt TARGET 1lss sizeafter finished end TARGET sym Eye candy AVR Studio 3 x does not check make s exit code but relies on the following magic strings to be generated by the compile job begin echo echo MSG BEGIN finished echo MSG ERRORS NONE end echo MSG END echo Display size of file sizebefore Gif f S TARGET elf then echo echo MSG SIZE BEFORE S ELFSIZE echo fi m m sizeafter Rif f S TARGET elf then echo echo MSG SIZE AFTER S ELFSIZE echo fi f Display compiler version information gccversion ES CC version Convert ELF to COFF for use in debugging simulating in AVR Studio or VMLAB COFFCONVERT OBJCOPY debugging X change section address data 0x800000 X change section address bss 0x800000 X change section address noinit 0x800000 X change section address eeprom 0x810000 coff S TARGET elf Gecho echo MSG_COFF TARGET cof COFFCONVERT O coff avr lt
14. 1 00E 5 58E 6 20E 6 82E 06 05 05 05 05 05 07 08 08 08 Inductances Limin Li Limax 2 64E 3 30E 3 96E 07 07 07 2 64E 3 30E 3 96E 07 07 07 2 64E 3 30E 3 96E 07 07 07 2 64E 3 30E 3 96E 07 07 07 2 64E 3 30E 3 96E 07 07 07 2 64E 3 30E 3 96E 07 07 07 2 64E 3 30E 3 96E 07 07 07 2 64E 3 30E 3 96E 07 07 07 2 64E 3 30E 3 96E 07 07 07 2 64E 3 30E 3 96E 07 07 07 2 64E 3 30E 3 96E 07 07 07 2 64E 3 30E 3 96E 07 07 07 Ecowatt 129 Ecowatt MAX1524 Power Losses Pin Pout PGND PrB PSET PSHDN PEXT Pcc 0 078 0 034969 0 0 0 0 0625 0 0 0625 0 25 0 190969 0 0 0 0 25 0 0 25 0 5625 0 390625 0 0 0 0 5625 0 0 5625 1 1 2544 0 0 190969 0 1 0 937 1 1 5625 7 0216 0 1 7947 0 1 2544 1 2544 1 2544 2 25 18 8347 0 6 25 0 1 5625 1 5625 1 5625 3 0625 62 8849 0 22 428 0 1 7947 1 8769 1 7947 3 74 62 8849 0 11 76 0 1 8769 1 9591 1 8769 4 635 62 8849 0 24 0 1 8769 1 8769 1 8769 6 25 62 8849 0 46 2319 0 2 0449 1 7875 2 145 6 875 62 8849 0 53 76 0 2 145 2 145 2 145 8 79 23 75 0 4 36 0 1 1236 1 1236 1 1236 Resistor Power Losses PR1 PRZ PR3 0 034969 0 0 0625 0 190969 0 0 25 0 390625 0 034969 0 5625 1 344 0 190969 1 7 0216 1 7125 1 5625 18 8275 6 4 2 34 52 338 24 3 8522 62 8849 48 0786 4 2848 62 8849 23 75 4 4944 40 6016 47 0249 5 625 62 8849 56 4616 7 205 16 2097 4 4944 9 130 Ecowatt Capacitor Power Losses Pcimin Pc1 Pcimax Pczmin Pc
15. 255 amp amp CountDownTimers i 0 CountDownTimers i kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk ok kk kk dk hg KA KA A K A A KAZ A AXA K KA ZA AA KA kck ck kk Function name Timer0 RegisterCallbackFunction a Returns None Parameters pFunc Purpose Set up functions to be called from the TIMERO COMP interrupt kk ck ck ck kk kk ck kk ck AA KK A AAA AA KK AKA A kc k ko ko K hh kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk BOOL Timer0 RegisterCallbackFunction TIMER C ALLBACK FUNC pFunc mt char i uint8 t i for i20 i TIMERO NUM CALLBACKS i if CallbackFunc i pFunc return TRUE for i 0 i lt TIMERO NUM CALLBACKS i if CallbackFunc i NULL CallbackFunc i pFunc return TRUE return FALSE OK KK I KK KKK KKK KKK I I IK RK KKEKK KKK KKK KK KKK KKK KK KK KK KA ZAZ A K AA KK KK k kk 115 Function name Timer0 RemoveCallbackFunction a Returns None Parameters pFunc i Purpose Remove functions from the list which is called int the TIMERO COMP interrupt ck ck ck ck ck kk ck KKK kk ck kk ck ck kk kk kk kk ko ck ko kv ko ko ko ko ko kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk BOOL Timer0 RemoveCallbackFunction TIMER CAL LBACK FUNC pFunc mt char i uint8 t i for i 0 i lt TIMERO NUM CALLBACKS i if CallbackFunc i pFunc CallbackFunc i NULL return TRUE return FAL
16. 754 743 732 7 20 709 697 685 673 661 649 636 624 611 599 586 574 562 549 5 37 524 512 500 488 476 464 452 440 429 418 406 396 385 374 3 64 354 344 334 324 315 306 297 288 279 271 263 255 247 240 2 33 225 219 212 205 199 193 187 l const int TEMP Celcius neg PROGMEM Negative Celcius temperatures ADC value from 1 to 15 degrees 815 825 834 843 851 860 868 876 8 83 891 898 904 911 917 923 y char degree CELCIUS char degree CELCIUS define FALSE 0 define TRUE FALSE char CONTRAST LCD INITIAL CONTRAST Start up delay before scrolling a string over the LCD LCD driver c extern char gLCD Start Scroll Timer define BOOL char define FALSE 0 define TRUE FALSE Variable from button c to prevent button bouncing extern unsigned char gButtonTimeout extern BOOL gAutoPressJoystick Used to indicate when the LCD interrupt handler should update the LCD mt jw char gLCD Update Required FALSE volatile char gLCD Update Required FALSE LCD display buffer for double buffering char LCD Data LCD REGISTER COUNT Buffer that contains the text to be displayed Note Bit 7 indicates that this character is flashing char gTextBuffer TEXTBUFFER SIZE Only six letters can be shown on the LCD With the variables one can select which part of the buffer to show volatile signed char gScroll vola
17. Parameters char log char to log to rs232 else print to screen int ADCResult ADC reading to convert Purpose Convert an ADC reading into a temp Ck ck ck ckck KK AKA A AA KA KK A Z A KA KK AKA A KA KK ko K ck kk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk void ADC2Temp int ADCresult int ADCresult 0 int ADCresult_temp 0 int Temp_int 0 int dif int top char Temp unsigned char i 0 char TL 105 char TR char VH char VL if ADCresult 810 If it s a negtive temperatur for i20 i lt 25 i Find the temperature if ADCresult lt pgm read word amp TEMP Celcius neg i add a decimal reading through liner interpolation if ADCresult lt pgm read word amp TEMP Celcius neg i f di f pgm read word amp TEMP Celcius neg i pgm read word amp TEMP Celcius neg i 1 top ADCresult pgm read word TEMP Celcius neg i 11 100 Temp int top dif 1 itt break LCD putc 0 Put a minus sign in front of the temperature else if ADCresult lt 800 If it s a positive temperature for i 0 i lt 60 i if ADCresult gt pgm read word amp TEMP Celcius pos i add a decimal reading through liner interpolation if ADCresult gt pgm read word amp TEMP Celcius pos i dif pgm read word amp TEMP Celcius pos i 1 pgm read word amp TEMP Celcius pos i top pgm read word
18. amp TEMP Celcius pos i 1 ADCresult 100 Temp int top dif 1 Ecowatt break else I the temperature is zero degrees i 0 LCD putec 0 Temp CHAR2BCD2 i Convert from char to bin TL Temp amp 0x0F 0 Find the low byte TH Temp gt gt 4 0 Find the high byte Temp CHAR2BCD2 Temp int VH Temp gt gt 4 0 VL Temp 6 OxOF 0 LCD putc 0 LCD character 1 is allready written to LCD putc 2 TH LCD putc 3 TL LCD putc 4 LCD putc 5 C LCD putc 6 N0 kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk ok kk kk dk ck ckckck KA AK A AK KAZ A AXA K KA ZA ck ck ckckckck kck k kk x Function name ADC2Volt Returns nothing x Parameters char log char to log to flash else print to screen int ADCResult ADC reading to convert Purpose Convert an ADC reading into a Voltage kkkkkxkxkxkxkxkxkxkkxkxkxkxkkxkxkxkkkkkxkxkxkxkxkkkkxkkkkxk kxk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk void ADC2Volt int ADCresult int ADCresult temp 0 char Temp char TL char VE char VL 106 float V ADC char VoltageHB char VoltageLB V ADC ADCresult VREF 1024 Calculate the voltage V ADC VADC 6 Multiply by 6 because of the voltage division VoltageHB V_ADC Store the high byte V ADC V ADC VoltageHB VoltageLB V ADC
19. bit define sbi x bit x BV bit set bit GNU compatability define cbi x bit x amp BV bit clear bit GNU compatability Button definitions define KEY NULL define KEY ENTER define KEY NEXT define KEY PREV define KEY PLUS define KEY MINUS OO BWNR O void Initialization void void OSCCAL calibration void void Delay unsigned int millisec define TEMPERATURE SENSOR 0 define VOLTAGE SENSOR 1 define LIGHT SENSOR 2 3 4 define CELCIUS define FARENHEIT define DIR SENSOR 4 this is effeted by the light and temp a little 1 07 is a compromise so reading can vary by 50mV this is okay as we are only using it analog to moonitor the battery voltage define VREF 2 900 define PWR MAX V OxBC 3 2V define PWR GOOD V 0xBO 3 0V define PWR LOW V 0x9E 2 7V average voltage define PWR MIN V 0x8D lt 2 4V define PWR ABS MIN V 0x75 lt 2 0V absolute minimum allowed battery voltage void ADC init char int ADC read void void ADC2Temp int ADCResult void ADC2Volt int ADCResult void Power check void char Temp_check void Ecowatt ifdef M162 define PINA MASK 1 PINAO 1 lt lt PINA1 1 lt lt PINA2 1 lt lt P INA3 1 lt lt PINA4 else define PINB MASK 1 lt lt PINB4 1 lt lt PINB6 1 lt lt PINB7 define PINE MASK 1 lt lt PINE2 1
20. compartment are written below 0 2e gt 207 Eq 1 207 4H gt 2H 0 Eg 2 Ecowatt Oxygen is suitable since it has high oxidation potential it is freely available and it combines with hydrogen ions coming via membrane to form water so there is no harmful waste The original design used a water tank with the electrode submerged in water To reduce the weight of each MFC an air cathode is proposed This cathode must be plated with a metal that increases the rate of reaction in Eg 2 These catalyst metals include platinum coated carbon electrodes and palladium electrodes Carbon cloth electrodes were donated by University of Minnesota Twin Cities Civil Engineering Department These cloth electrodes provide a large surface area for Geobacter to populate and are flexible and thin to reduce the diffusion distance from electrode to membrane to electrode Proton Exchange Membrane From the research conducted and recorded in the papers shown in the research section two proton exchange membrane options were presented The first was a Nafion 117 membrane that is traditionally used in research Hydrogen Fuel Cells This membrane is thicker and more robust than the alternative of natural cellophane The Nafion membrane was discovered in 1960 by creation of sulfonated tetrafluorethylene which was permeable to cations Nafion is resistant to chemical attack and impermeable to water The Nafion information sheet is located in Appendix VI The
21. given that the power supply used only has a current of approximately 300mA Another problem includes the fact that the output from the regulator is not a flat response Instead the output is noisy and sometimes oscillates like a sine wave This problem will go away with the introduction of a feedback capacitor attached to the connection of the voltage divider of R1 and R2 with the FB pin on the MAX1524 By placing the capacitor here one can decrease the ripple on the output Furthermore the MAX1524 chip is in a non bootstrapped configuration right now By putting the MAX1524 chip in a non bootstrapped configuration the chip gave a higher output which was contrary to all expectations especially given what the datasheet for the MAX1524 stated By fixing the inductor increasing the current and adding a feedback capacitor putting the chip configuration back into bootstrap mode will become ideal The idea is that by doing so the chip will operate according to plan If this plan does not work further Ecowatt research will become necessary to offset any potential problems Consulting with Professor Brouwer has shown that by rewiring the SHDN pin to the input instead of Vcc the voltage regulator can perhaps achieve the desired voltage While the regulator responds to varying resistor loads on the output side the amount of response is minimal with respect to the amount of resistance put on the output 7 Conclusion 7 1 Lessons Learned The m
22. lt SE Enable Power down mode asm volatile sleep if PINB amp 0x40 press UP to wake from SLEEP PowerSave FALSE for i 0 i lt 20 i setall LCD segment register to the variable uc Segments amp pLCDREG test i 0x00 sbi LCDCRA 7 enable LCD input getkev Read buttons gPowerSaveTimer 0 reset seconds until sleep timer SMCR 0 Just woke disable sleep End Main loop return 0 Figure 35 Main function of Monitor Firmware Part 2 of 2 Ecowatt 6 4 11 Fuel Cell Arrangement Alternatives and Analysis Three options exist for the fuel cell arrangement Like with a circuit the arrangement has the potential to be in series or in parallel Despite the continuing research prior knowledge concerning the arrangement gives weight to each of the possibilities If the fuel cells are in series the voltages of each cell will add together However a problem exists for serial connection If one of the cell s output becomes unusable it will short the circuit between the rest of the cells In the final design this has the potential to become difficult to repair As a result the entire battery can become crippled by one small malfunction such as the death of the bacteria in one of the cells On the other hand one can wire the fuel cells in parallel While this option can possibly suffer from lower output it has a higher guarantee for success That is it is less likely to
23. 0 0007569 100000 0 252 0 00000252 0 00252 0 00063504 1000000 0 311 0 000000311 0 000311 0 000096721 11 28 07 data taken at 1 30 pm R ohm V v IA I mA P mW 10 0 0 0 0 100 0 002 0 00002 0 02 0 00004 1000 0 021 0 000021 0 021 0 000441 10000 0 134 0 0000134 0 0134 0 0017956 100000 0 28 0 0000028 0 0028 0 000784 1000000 0 316 0 000000316 0 000316 0 000099856 Ecowatt ET 11 29 07 data taken at 8 am R ohm V v I A I mA P mW 10 0 0 0 0 100 0 001 0 00001 0 01 0 00001 1000 0 008 0 000008 0 008 0 000064 10000 0 065 0 0000065 0 0065 0 0004225 100000 0 228 0 00000228 0 00228 0 00051984 1000000 0 303 0 000000303 0 000303 0 000091809 11 29 07 data taken at 4 30 pm R ohm V v IA I mA P mW 10 0 0001 0 00001 0 01 0 000001 100 0 0008 0 000008 0 008 0 0000064 1000 0 0081 0 0000081 0 0081 0 00006561 10000 0 066 0 0000066 0 0066 0 0004356 100000 0 246 0 00000246 0 00246 0 00060516 1000000 0 342 0 000000342 0 000342 0 000116964 11 30 07 R ohm V v IA mA P mW 10 0 0001 0 00001 0 01 0 000001 100 0 0007 0 000007 0 007 0 0000049 1000 0 007 0 000007 0 007 0 000049 10000 0 057 0 0000057 0 0057 0 0003249 100000 0 206 0 00000206 0 00206 0 00042436 1000000 0 277 0 000000277 0 000277 0 000076729 12 01 07
24. 02 0 00000004 0 00004 1000 0 023 0 000023 0 023 0 000000529 0 000529 10000 0 134 0 0000134 0 0134 1 7956E 06 0 001796 100000 0 296 0 00000296 0 00296 8 7616E 07 0 000876 1000000 0 35 0 00000035 0 00035 1 225E 07 0 000123 11 24 07 R ohm V v I A I mA P W P mW 10 0 0 0 0 0 100 0 002 0 00002 0 02 0 00000004 0 00004 1000 0 018 0 000018 0 018 0 000000324 0 000324 10000 0 118 0 0000118 0 0118 1 3924E 06 0 0013924 100000 0 247 0 00000247 0 00247 6 1009E 07 0 00061009 1000000 0 277 0 000000277 0 000277 7 6729E 08 0 000076729 11 26 07 R ohm V v I A I mA P W P mW 10 0 0 0 0 0 100 0 001 0 00001 0 01 0 00000001 0 00001 1000 0 014 0 000014 0 014 0 000000196 0 000196 10000 0 094 0 0000094 0 0094 8 836E 07 0 0008836 100000 0 215 0 00000215 0 00215 4 6225E 07 0 00046225 1000000 0 25 0 00000025 0 00025 6 25E 08 0 0000625 Second setup measured and calculated parameters 11 27 07 R ohm V v IA I mA P mW 10 0 0 0 0 100 0 004 0 00004 0 04 0 00016 1000 0 034 0 000034 0 034 0 001156 10000 0 08 0 000008 0 008 0 00064 100000 0 135 0 00000135 0 00135 0 00018225 1000000 0 15 0 00000015 0 00015 0 0000225 11 28 07 data taken at 9 am R ohm V v IA I mA P mW 10 0 0 0 0 100 0 001 0 00001 0 01 0 00001 1000 0 011 0 000011 0 011 0 000121 10000 0 087 0 0000087 0 0087
25. Bill of Materials retener a etse EA dada ka sak banan GA DAGA 35 Table 7 Monitor Voltage Level Display eses eee aso a aaa aaa aaa aa aaa aaa enne enne nn 66 Table 8 Monitor Temperature Level Display eeeess eee aaa aaa aaa aaa aaa eene enne 67 Fcowatt FR 1 Executive Summary The Ecowatt Biobattery successfully addresses and overcomes many of the previous design problems inhibiting the proliferation of Microbial Fuel Cells MFCs as a viable energy alternative The research showed that MFCs have been implemented in previous studies at the university level but no viable products have come to fruition Ecowatt testing early on proved the MFC concept achieving an average closed circuit voltage output of 0 3V for over a week without feeding An assortment of sources indicated that more power can be achieved with a more efficient proton exchange membrane Further testing proved the functionality of a new cost effective membrane cellophane The electrodes are assembled adjacent to the membrane in a sandwich method for optimum proton exchange efficiency and the sandwiches are arranged in a cube structure to allow for easier feeding of multiple cells and to maximize volumetric efficiency Even with all of these improvements the Biobattery still reguires over 90 cubes to provide proper USB power it fits roughly into a 2 X 2 X 3 cubic space and weighs about 500lbs when filled with water Further
26. IEEE std 1149 1 compliant Interface Boundary scan Capabilities According to the JTAG Standard Extensive On chip Debug Support Programming of Flash EEPROM Fuses and Lock Bits through the JTAG Interface Peripheral Features 4 x 25 Segment LCD Driver Two 8 bit Timer Counters with Separate Prescaler and Compare Mode One 16 bit Timer Counter with Separate Prescaler Compare Mode and Capture Mode Real Time Counter with Separate Oscillator Four PWM Channels 8 channel 10 bit ADC Programmable Serial USART Master Slave SPI Serial Interface Universal Serial Interface with Start Condition Detector Programmable Watchdog Timer with Separate On chip Oscillator On chip Analog Comparator Interrupt and Wake up on Pin Change Special Microcontroller Features Power on Reset and Programmable Brown out Detection Internal Calibrated Oscillator External and Internal Interrupt Sources Five Sleep Modes Idle ADC Noise Reduction Power save Power down and Standby O and Packages 53 Programmable I O Lines 64 lead TQFP and 64 pad QFN MLF Speed Grade ATmega169V 0 4 MHz 1 8 5 5V 0 8 MHz 2 7 5 5V ATmega169 0 8 MHz 2 7 5 5V 0 16 MHz 4 5 5 5V Temperature range 40 C to 85 Industrial Ultra Low Power Consumption Active Mode 1 MHz 1 8V 350HA 32 kHz 1 8V 20pA including Oscillator 32 kHz
27. It is also obtainable in a pure form from the ATCC American Type Culture Collection ATCC is a non profit organization that collects preserves and distributes pure cultures of living organisms The ATCC provides a specific medium for each organism where they guarantee the continued survival of the organism The medium is ATCC 1768 Broth Medium for Geobacter metallireducens This ATCC medium production procedure is located in the Appendix IV The species is anaerobic and produce more electricity when in an anaerobic environment The gas environment is highly recommended to Fcowatt IEEE be 80 Nitrogen and 20 Carbon Dioxide Geobacter metallireducens also reguires Wolf s Vitamin and Mineral solutions The feed solution was decided to be the media recommended for guickest growth and reproduction of Geobacter This increased activity corresponds directly with the consumption of acetate and production of free energized electrons For setup of microbial fuel cells are found in the appendix The typical medium used for the Geobacter species includes ferric citrate as the electron acceptor and sodium acetate as the general organic feed These chemicals are for the purpose of this project obtained from the biology department at Calvin College Electrodes The MFC will include two electrodes anode and cathode for transferring electrons The anode is the negative terminal where the electrons are deposited and transferred by Geobacter as electr
28. It requires minimal service and service must be possible without technical training The waste must be easily disposable and food should not be wasted Design Alternatives Analysis The typical feeding setup used in research on this type of MFC generally involves large scale feeding systems that consume great amounts of power and are focused on optimum output rather than overall efficiency For Ecowatt other options had to be analyzed Continuous feeding provides the most stable and consistent feed supply for the MFCs but it is difficult to maintain and generally not possible on the scale of this project On the other hand batch feeding is generally too difficult for the average user to manage and feedings are frequent enough that the process may be cumbersome To satisfy the requirements the Biobattery necessitates a hybrid between the two systems types Decision The Biobattery incorporates a batch fed continuous feeding process to provide a steady food supply to the MFCs with minimal upkeep while requiring no additional power First of all the Food Supply Bag contains a feed solution in a sealed oxygen free environment and the Ecowatt Water Tank contains water open to the air The Food Supply Bag is suspended above the Anode Cubes and a siphoning action draws the food supply from the Food Supply Bag into the Anode Cubes and the waste from the MFCs into the Water Tank below the Anode Cubes Implementation PA The flow of the Fo
29. Returns int ADC Parameters None d Purpose Do a Analog to Digital Conversion ck ck ck ck ck Ck ck kk ck kk ck KA KK AA AA AKA KK AKA ko kc ko KK e hh kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk int ADC read void char i int ADC_temp int ADCr 0 To save power the voltage over the LDR and the NTC is turned off when not used This is done by controlling the voltage from a I O pin PORTF3 sbi PORTF PORTF3 Enable the VCP VC peripheral sbi DDRF PORTF3 sbi ADCSRA ADEN Enable the ADC do a dummy readout first ADCSRA 1 lt lt ADSC single conversion while ADCSRA amp 0x10 wait for conversion done ADIF flag active do Ecowatt for i 0 i1 lt 8 i do the ADC conversion 8 times for better accuracy ADCSRA 1 ADSC 24 do single conversion while ADCSRA amp 0x10 wait for conversion done ADIF flag active ADC temp ADCL read out ADCL register ADC temp ADCH lt lt 8 read out ADCH register ADCr ADC temp accumulate result 8 samples for later averaging ADCr ADCr gt gt 3 the 8 samples average cbi PORTF PORTF3 disable the VCP cbi DDRF PORTF3 cbi ADCSRA ADEN disable the ADC return ADCr kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk ok kk kk dk hg KA KA A K A AZ KAZ A ZA K KA ZA AA kck ck ck k kk Function name ADC2Temp Returns nothing
30. a D27 D28 29 25 D26 D22 D23 D10 20 D21 ATMEGA 169V 1MC Ecowatt 10 9 Appendix IX Monitor Source Code Written in C main c J RR RRR KKK Ok kk Kk kk kk kk kk Kok KKK koe ek ek e ke k kk ck ck ckck ck ck ck e ck KA ck ck ck ck KA AA AK AKA KA ck ck ckck ck ck KK LO OLBieeil eef malm c Author s Achyut Shrestha Target s ATmegal69 Compiler AVR GCC 3 3 1 avr libc 1 2 A Description AVR Butterfly main routines Revisions 1 0 YYYYMMDD VER COMMENT SIGN 20080503 main routine Achyut Shrestha 77 kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk ck ck ck ck ck kk kk kk ck ck KA AKA AAA AA KK A ZA k KA Kk hh h w include lt avr io h gt include lt avr interrupt h gt include lt avr pgmspace h gt include lt avr sleep h gt include lt inttypes h gt include main h include lcd driver h include timer0 h include RTC h define pLCDREG test char 0xEC extern uintl6 t gPowerSaveTimer External Counter from RTC c uint16 t PowerSaveTimeout 30 Initial value sleep after 30 sec extern uint16 t gWakeUpTimer External Counter from RTC c uintl6 t WakeUpTimeout 10 Initial value wake up after 10 sec const int TEMP Celcius pos PROGMEM Positive Celcius temperatures ADC value from 0 to 60 degrees 806 796 786 775 765
31. areas to improve on in the future would be efficiency of the electrodes implementation of Platonized electrodes to eliminate the need for a water cathode chamber and about 55 of the weight and research into more effective fabrication methods to prevent leaks and allow for better utilization of cube surface area Over the course of this project the team has learned valuable lessons First of all it is important to maintain and adhere to a schedule Ecowatt was successful in this respect for the first semester and then fell behind during the prototyping and testing stage Moreover prototyping and testing are much more time consuming than originally anticipated and long lead times on part orders can drastically impact a team schedule The team also learned the importance of enlisting the help of others in the industry and other universities Assistance from researchers and those in the industry was paramount in the acguiring of parts far outside the meager Ecowatt budget Finally the team experienced the joy of seeing a project grow from brainstormed ideas to a completed design over the course of the year In light of this the project is clearly successful Fcowatt ICE 2 Introduction Ecowatt is a four member senior design group of senior engineers at Calvin College who seek to have a positive electrical impact on the world This team of four engineers includes sections of three of the engineering concentrations offered at Calvin Two member
32. cbi LCDCRA LCDIE DEBUG gScroll 0 EOL FALSE if gLCD Update Required TRUE Duty cycle of flashing characters if gFlashTimer lt LCD FLASH SEED gt gt 1 flash 0 else flash 1 Repeat for the six LCD characters 112 for i 0 i lt 6 i if gScroll i gt 0 66 EOL We have some visible characters gTextBuffer i gScroll c flash c amp 0x80 1 0 c c 6 Ox7F if c N0 EOL i 1 Lf End of character data else or Check if this character is flashing if c flash amp amp flash LCD WriteDigit i else LCD WriteDigit c i Copy the segment buffer to the real segments for i 0 i lt LCD REGISTER COUNT i pLCDREG i LCD Data i Handle colon if gColon pLCDREG 8 0x01 else pLCDREG 8 0x00 I the text scrolled off the display we have to start over again if EOL 1 gScroll 6 else gScroll No need to update anymore gLCD Update Reguired FALSE LCD timer is used when scrolling text if LCD timer 0 if gScroll lt 0 EOL LCD timer LCD TIMER SEED 2 else Ecowatt LCD timer LCD TIMER SEED gFlashTimer is used when flashing characters if gFlashTimer LCD FLASH SEED gFlashTimer 0 else gFlashTimer kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kk ck
33. condition was physically to simulate the over current condition The MAX1607 IC used to detect the over current or short circuits condition produces a logic high whenever this condition occurs This logic high interrupts the micro controller to take some preventive actions In order to produce this interrupt i e to send a logic high signal to PE4 pin the desired pin had an external voltage applied to it which interrupted the micro controller as expected With the triggering of the interrupt the output of MAX1607 IC was disabled The micro controller sent a logic high signal to enable pin in MAX1607 IC via port PBO Only in removing the interrupted event condition can the micro controller send a logic low signal to enable the pin to reactivate the output Power save mode Every 30 seconds after the activation of the Monitor the Monitor went into power save mode This was easy to test by timing the event against a regular stopwatch which showed that the Monitor went into power save mode each time In order to see the difference in power consumption by the Monitor it was necessary to the power consumption during active mode and the power saving mode The power supplied to the Monitor was 3V During active mode with text scrolling in the LCD along with the ADC measuring voltage and temperature the power consumed was 2 13mW while during power save mode the power consumed by Monitor was 24uW The ratio of power in active mode to power save mode is al
34. design alternatives reflect the design criteria in this case 4 4 Feeding Process Microbial fuel cells contain bacteria that must have a sufficient supply of food to survive In fact the power generation performance of a microbial fuel cell is dependent on food supply Since the bacteria must live in an anaerobic environment the method of adding the food to the cell solution requires finesse The food supply can be added to the cell solution periodically in controlled amounts through a process called batch feeding At feeding time the solution must be maintained while the food supply is added and the waste solution is simultaneously removed Unfortunately batch feeding must be done at relatively frequent intervals and the power output can drop significantly starting about one week after last feeding To solve the problems associated with batch feeding researchers have employed continuous feeding Continuous feeding X maintains a steady flow of food supply into the cell and waste solution out of the microbial fuel cell Requiring little maintenance or upkeep On the other hand continuous feeding systems are complicated and expensive to implement Pumps would be necessary to continually draw the food supply into the microbial fuel cell the power for such pumps would use more energy than the Biobattery could possibly generate rendering them unfeasible To optimize the benefits and overcome the drawbacks to both batch and continuous feed
35. ee aaa onen no nn 87 10 3 Appendix Ill MEC Testing Da a ocalona A A EE 88 10 4 Appendix IV Product Information Sheet of MO 53714 WONNA 93 10 5 Appendix V Membrane Testing Data ssrennannnnvnnnesnnvrvnssnevnvnsenennrnnnsennrrvesennnnvnsssnnnns 94 10 6 Appendix VI Nafion 117 Information sheet sseeaaa ae a aaa a aaa aaa aaa eazaaaaacca 95 10 7 Appendix VII Software TOGI sai WC WE HU 96 10 8 Appendix VIII ATMega169 Specifications eeeuua ooo ea aa aaa aaa aaa ae ea aa aaa eaaaaaaaaca 98 10 9 Appendix IX Monitor Source Code Written in C 100 10 10 Appendix X Regulator Test Results rrsnnrrvrrannnnvnrsnennrnnnnennvrvnssnsnnvnsenennvnnnsennrsensene 124 Fcowatt IEEE 10 1 Appendix I Biobattery Assembly Instructions 50mL Test Tubes with Salt Bridge No Autoclave Not Final Design Note Prepared Bacteria Test Tubes from this procedure expire in about a week but steps 1 3 do not expire and can be completed in large guantities in advance Testing instruments Multimeter Resistors Cables wires alligator clips Oscilloscope Data logger Procedure 1 Prepare the wire and electrode 5 min tube Epoxy Curing Time a Obtain a 10 wire with good conductivity non copper b Using a box cutter cut a portion of electrode that will fit into the test tube about 1cm X 0 5cm X 3cm larger electrodes should result in higher power output C Attach the elect
36. lt lt PINE3 1 lt lt PINE4 endif ifdef M162 define BUTTON A O NORTH define BUTTON_B 1 EAST define BUTTON C 2 WEST define BUTTON D 3 SOUTH define BUTTON O 4 PUSH else define BUTTON A 6 UP define BUTTON B 7 DOWN define BUTTON C 2 LEFT define BUTTON D 3 RIGHT define BUTTON O 4 PUSH endif void PinChangeInterrupt void void Button Init void char getkey void char ButtonBouncing void extern char gPowerSaveTimer extern volatile char gPowerSaveTimer extern uint16 t PowerSaveTimeout Initial value sleep after 30 sec mt FALSE volatile unsigned char gButtonTimeout FALSE unsigned char gButtonTimeout volatile char KEY NULL volatile char KEY VALID FALSE finclude lt avr pgmspace h gt Functions mt void LCD puts f char pFlashStr char scrollmode void LCD puts f const char pFlashStr char scrollmode void LCD puts char scrollmode flash pStr char void LCD UpdateRequired char update char scrollmode void LCD putc char digit char character 117 void LCD putc uint8 t character void LCD Clear void void LCD Colon char show void LCD FlashReset void char SetContrast char input digit char Function declarations char CHAR2BCD2 char input unsigned int CHAR2BCD3 char input kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kkkkkk
37. main drawback to the Nafion membrane is the Cellophane Test Setup 1 4E 13 1 2E 13 y 7 6 578 153 374x 83 527 418 843 R 0 984 1E 13 8E 12 6E 12 4E 12 a T rI c 9 U m gt I c hm c o o c o O 2E 12 1000 Time mins Figure 19 Cellophane Membrane Testing Fcowatt IEEE high cost Nafion with appropriate thickness for Ecowatt would cost 297 plus shipping and handling for an 8 by 10 rectangle Ecowatt had the opportunity for a fellow researcher Professor Ray Hozalski at the University of Minnesota to provide a sample of Nafion 117 for testing Natural cellophane has similar proton exchange properties not as well researched but less than 5 for more than 5 yards Testing was completed to compare the proton flux through a 1cm circle of membrane Testing Data may be found in Appendix V The Cellophane was found to have a proton flux of 85 of the more expensive Nafion membrane This 15 decrease in proton flux does not justify the use of the significantly more expensive membrane The cellophane membrane was the chosen membrane for final design Nafion Test Setup 3 5E 11 3E 11 y 7 252 425 921x 24 358 671 242 2 2 5E 11 GRA ka m mr e 1E 11 I lt c 9 o k gt L c 2 hu o o c o o 5E 10 20 Time mins Figure 20 Nafion117 Membrane Testing 6 4 5 Fuel Cell Ar
38. minimum voltage current and power to enable the circuit to operate correctly Beyond this point the circuit needed adjustment to make sure that the voltage level of 5 0V and current level of 100mA to 500mA preferably around 300mA came from the voltage regulator s output The circuit functionality must be verifiable and not harm the microbes in the MFC Design Alternatives and Analysis The first design used specialized parts such as a low input linear voltage regulator and a low input voltage bipolar junction transistor BJT If the current output of the MFC dipped the resulting voltage will not affect the output voltage and the circuit s functionality This design has an active voltage measurement that increases the energy loss in the circuit The second design used a TPS62100 switching voltage regulator from Texas Instruments in a configuration with a diode four resistors and four capacitors This design requires more power than the second design but this design is 40 more efficient This circuit requires an additional current source The problem with this addition is that the current source circuit requires an external reference in order to supply the desired current Given the scenario with the Biobattery this is not possible to do since it would require an addition source of power that the Biobattery could not supply One of the pins has a high current requirement too to activate the chip into a running mode The third design wo
39. oaza aa oaza aaa aa aaa aaa oaza aaa nnne nne nnns 41 Figure 16 Component Anode Cube e esee eee oe aaa aaa aaa aaa aaa aaa aaa aaa oaza aaa ae nnne nnns 42 Figure 17 Component Feed Bladder ee eee oe eau aaa aa anna aaa aaa aaa aaa aaa az aaa nnne 43 Figure 18 Schematic of Microbial Fuel Cell e uooo see eene enne 44 Figure 19 Cellophane Membrane Testing rrnrnnnnannrrvnnannnnvnnsnennrnnnsennrrensennnnnnssnennrnnnsennrrenssnnnnenee 47 Figure 20 Nafion117 Membrane Testing iureeciire reisen ta eto oak a naka WAGA WA bonore raras ak AA 48 Figure 21 Power Management Block Diagram esses eene enne eene nnns 49 Figure 22 Regulator Circuit DIABTATM e aiite Rc c reU Rr Rea te era Pu Da z ad 55 Figure 23 MAX1607 Circuit Layout essen nennen a rrr rr nnne 56 Figure 24 Monitor Block Diagram aaa aa k aka esa bredside 59 Figure 25 AVR Butterfly Kit c 60 Figure 26 Voltage Port Scheratle iios co ceti Rr W Ok EOG 61 Figure 27 Temperature Sensor Schematic esses esee eene ener nnns 62 Figure 28 USI Port SEheralibu wieki dead Ga od D de Han uc cu acid 63 Fig re29 LCD Erie qi rz iem T AGA 64 Figure 3D Port B SCHEMA UC dO GO keen 65 Figure 31 MFC Power Check Function aoi GG wiki ai 66 Figure 32 Temperature Check Function u mmesmemersanesresiuiemeernvd vi
40. off all of the ethanol c Using a sterile needle pierce the cap of the culture solution test tube d Withdraw about 2mL culture solution e Add the culture solution to the media solution test tube by piercing the cap and injecting the culture 8 Place each Prepared Bacteria Media Solution in a 30 C Agitator Bath 1 min 10 2 Appendix II Bladder Filling Procedure IV Bag Preparation with Autoclave Note Prepared Media Solution expires in about a week unless autoclaved 1 Prepare Media Solution 1L media produced 45 mins a Boil 400mL de ionized water in a 250mL Erlenmeyer Flask b Add 13 7g Sodium citrate 13 7g L c Cool to room temperature using an ice bath d Adjust the pH to 6 0 using 1M NaOH e Add to the solution i 600mL de ionized water ii 2 5g NaHCO3 iii 0 25g Ammonium Chloride iv 0 60g NaH PO H 0 v 0 10g KCI vi 6 8g Sodium Acetate f Degas the media in a 2L Erlenmeyer Flask with side arm g Bubble N in the solution for 10 mins h Bubble CO in the solution for 5 mins and quickly cork i Remove a small sample and test pH 5 5 7 5 acceptable 2 Fill IV bags with Media 2 bags of 500mL 25 mins autoclave a Empty and Wash IV bags b Fill each IV bag with 500mL and close c Autoclave overnight i Label and place in Biology Lab Core ii Ask Lori Keen to Autoclave overnight 3 Add Vitamin and Mineral Solutions Repeat for each IV bag 5 mins a Using a syringe and needle add 0 64mL of
41. power source must have a reduced environmental impact by not using toxic or harmful chemicals be more easily disposed than conventional batteries and have a longer lifespan It must also be easy to operate and provide a reasonable amount of stable power in usable nominal USB Standard values without requiring frequent or expensive maintenance Ecowatt 3 2 Project Objectives For this project Ecowatt will design and create a prototype for a microbial fuel cell or Biobattery The term Biobattery for the purposes of this project refers to a device which generates power by Geobacter a type of microbial organism The Biobattery designed by Ecowatt will consist of a Microbial Fuel Cell MFC system comprising a Feed and Water System an Output Regulator and a MFC Monitoring System All features of the case design must be reasonably robust and leak resistant The case must be easy to carry and intuitive to use The Biobattery should be contained in an attractive package that appeals to the target market Each MFC contains two compartments separated by a proton exchange membrane that generate an electric charge as a result of the eating behavior of the microbes MFC design will also include specifications for the appropriate electrodes and a proton exchange membrane between the two solutions The Feed and Water System will manage the flow of feed solution into the MFC as well as the flow of water solution out of the MFC The Feed an
42. short out from the failure of one fuel cell The difference here is akin to how a string of lights works If one goes out they all go out versus having one go out while the others still work properly For the purpose of having a reliable current and voltage the fuel cell arrangement decision needs careful consideration Therefore Ecowatt decided to use a combination of both parallel and series for the fuel cell arrangement To expound imagine a string of lights running in parallel with another string of lights Each string of lights is in series by themselves hence if one light goes out they all go out Likewise for the fuel cell arrangement this result is undesirable Now imagine that the lights are electrically connected at the ends so that the power source powers both light strands Unfortunately power between the strands becomes divided up so that the light given off from each strand of power is dimmer than if each strand were to receive power by itself from separate sources Again this result is undesirable for the fuel cell arrangement Consequently the design for the fuel cell arrangement requires a compromise between the two of these options which leads to the third option combining the two previous options By running the strands of lights in parallel and connecting them between every light with a small resistance each light will run in series with the next light while being in parallel with the next light on the other strand of ligh
43. to ensure that the Monitor itself needs little power to operate Since the Biobattery is a green product it is essential that any component used for monitoring the Ecowatt system be RoHS compliant and lead free The information relayed to the user must display in a user friendly manner so he she can understand the system status Design alternatives and analysis There are different ways to monitor each of the variables mentioned above The next section will discuss each of those variables in detail Voltage output from MFC An analog or a digital voltmeter can monitor the voltage An analog voltmeter will use no power from the MFC It is a mechanical system with coil and spring which will produce a deflection and corresponding reading One can calibrate the device to read the voltage output level from the MFC A digital voltmeter is more complex It will require at least three main components an ADC a micro controller and an output unit such as an LCD LED etc Since these are all electrical components they will consume power However power consumption by the digital circuit is very little A typical IC consumes power in the milli watt range A digital unit is more reliable than an analog unit is Both the analog and digital unit need shielding in some way from the water contained in the Biobattery system An analog unit will rust over time from moisture just as the digital circuit will fail too Feed waste level The feed and waste nee
44. 0000 0 185 0 00000185 0 00185 0 00034225 1000000 0 267 0 000000267 0 000267 0 000071289 Ecowatt Ecowatt 10 4 Appendix IV Product Information Sheet of ATCC 53774 ATCC NUMBER 53774 ORGANISM Geobacter metallireducens Type strain GS 15 This material is cited in a U S and or other Patent Application and may not be used to infringe the patent claims CITATION STRAIN If use of this strain results in a scientific publication it should be cited in that manuscript in the following manner Geobacter metallireducens ATCC 53774 ATCC MEDIUM 1768 Broth metallireducens Medium for Geobacter Milli Q H20 800mL Ferric citrate Sigma F 6129 13 70 g Vitamins see below 10mL Minerals see below 10mL NaHCO 2 50g NH Cl 0 25g NaH PO4 H20 0 60 g KCI 0 1g Sodium acetate 6 8 g Heat about 400 ml of Milli A H20 on a Add ferric citrate allow to dissolve then cool to room hot stir plate to near boiling temperature in a slurry of ice bring the volume of Milli A H20 up to 800 ml by adding 400 ml Milli Q this quickly cools the media to room temp Adjust the pH to 6 0 using 10N NaOH When the pH approaches 5 0 add the NaOH drop wise The approximate volume of 10N NaOH per liter is 6 ml Add the remaining ingredients and bring the final volume up to one liter with Milli A H20 Bubble the medium with 80 N and 20 CO The final pH should be around 6 8 7 0 This medium
45. 1 8V 40HA including Oscillator and LCD Power down Mode 0 1pA at 1 8V Fcowatt IEEE 10 8 2 Schematic PF 7 4 var H 0100 100N 16V X7R C101 voltage reader D 100N 16V X7R m N PFO erature sensor GND L100 el kx 4 yaco 2 e J C102 100W 16V X7R N 100N_16V_X7 GND N 6 te ofa kan GND TIPPPPHEPPETERP d 1U 16V X7R AEETI Oram mtwor Onda O Hu HB am dddaaaaa 000 CDCAP 1 L H rear UR 88 CON3 PA3 AVR RxD j PEO RED DEBS SEGO PA4 AVR TxD 7 q PEL TXD SEGL PAS BE rs PEL AINO XCK SEG2 PAS PE g PEHAINL SEG3 PA 7 PEA SCL USCE SEG4 PG2 g PES SDA DI SEG5 PC PEG DO 8EG6 PCS PET _ 8EG7 PC5 PBO SS SEG8 PC4 PBL SCK SEG9 PC3 PB2 NOSI SEG10 PC2 PB3 NISO SEG11 PCl PB4 0C0 Me SEG12 PCO re OCLA z 23 I used PB6 OC1B ga 008 BOO _ SBG14 PG m uunw ooor tiu NEL BBSERBEBRR NNI amp BoODDDODD A oji v UZb RRA SERIE qqHEBBBEBB BOW ADAR OHNOWAOM ADRA SGH HARARAANA A AAAS Pr Oe Oe Ar Oe AA MIAO ALN MOI JO JA Of AA r HJN O N O INIA ALIA INTE mm vec O 2 jo pec E EZ IEEE Los a AIAIAIAIAIAIAIA D O OJOJOJOJOJOJO d H MINNIE MINE IR100 10K N RESET gt EL mA n A C106 C14 1ON_50V_ XTR 100N 16V X7R N N GND GND r Figure 43 ATMega169 Schematic 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 slsisslalslelalalsl l ll
46. 2 Pczmax Pc3 PCFF 2 81E 3 13E 3 44E 4 23E 3 13E 9 76E 07 07 07 3 46E 07 3 85E 07 07 09 10 1 13E 1 25E 1 38E 2 31E 1 25E 5 33E 06 06 06 1 89E 06 2 10E 06 06 08 09 2 53E 2 81E 3 09E 4 73E 2 82E 1 09E 06 06 06 3 87E 06 4 30E 06 06 08 08 4 50E 5 00E 5 50E 1 52E 5 01E 3 50E 06 06 06 1 24E 05 1 38E 05 05 08 08 7 03E 7 81E 8 59E 8 31E 5 01E 2 14E 06 06 06 6 80E 05 7 55E 05 05 08 08 1 01E 1 13E 1 24E 2 25E 6 97E 1 04E 05 05 05 1 84E 04 2 04E 04 04 08 07 1 38E 1 53E 1 68E 7 61E 8 59E 2 95E 05 05 05 6 23E 04 6 92E 04 04 08 07 1 80E 2 00E 2 20E 7 61E 9 39E 6 29E 05 05 05 6 23E 04 6 92E 04 04 08 07 2 14E 2 38E 2 61E 7 61E 9 39E 1 75E 05 05 05 6 23E 04 6 92E 04 04 08 06 2 66E 2 95E 3 25E 7 61E 1 02E 1 75E 05 05 05 6 23E 04 6 92E 04 04 07 06 2 81E 3 13E 3 44E 7 61E 1 13E 1 75E 05 05 05 6 23E 04 6 92E 04 04 07 06 4 05E 4 50E 4 95E 2 94E 5 62E 6 78E 05 05 05 2 41E 04 2 67E 04 04 08 07 MOSFET Power Diode Power Inductor Power Losses Losses Losses Pais Po1G Pa1D PD1in PD1out PLR Pwh 0 O 0 0625 0 0625 0 034969 0 0625 1 03E 02 0 0 0 25 0 25 0 190969 0 25 4 13E 02 0 O 0 5625 0 5625 0 390625 0 5625 9 28E 02 0 1 1 5625 1 5625 1 2544 1 1 65E 01 0 1 2544 8 2369 7 37 6 8644 1 5625 2 58E 01 0 1 5625 20 1894 21 06 18 5725 2 4336 4 02E 01 0 1 8769 31 2225 29 205 24 3386 3 71 7 42E 01 0 1 9591 47 0249 46 5491 27 5058 4 6 60E 01 0 1 9591
47. 2081 ZE VTE ko TE 0x1550 U u 0x4448 N v 0xc550 W w 0xc028 X tx 0x2028 Jf Xt que Iyi 0x5009 Z z 0x0000 Not defined 0x0000 N Not defined 0x0000 Not defined 0x0000 Not defined 0x0000 72 M l uint8 t gSECON uint8 t gMINUTE uint8 t gHOUR uint8 t gDAY uint8 t gMONTH mtE unsigned int gYEAR mtA char gPowerSaveTimer 0 char dateformat 0 uint16 t gPowerSaveTimer 0 uint16 t gWakeUpTimer 0 uint8 t dateformat 0 mtE U RM se Lookup table holding the length of each month The first element is a dummy mt this could be placed in progmem too but the arrays are accessed quit often so leaving them in RAM is better char MonthLength 13 0 31 28 31 30 31 30 31 31 30 31 30 SL char TBL CLOCK 12 when displaying 12H clock 12 D 24 3 Ap Bp 6 Ty By 9 10 LL U2 dy 2 Sp 4 Sp 6 5 7 8 9 10 114 table used char clockformat CLOCK 12 set initial clock format to 12H different date formates text only mtA flash char DDMMYY flash char AMERICAN DATE TEXT MMDDYY EUROPEAN DATE TEXT 101 flash char CANADIAN DATE TEXT YYMMDD const char EUROPEAN DATE TEXT PROGMEM DDMMYY const char AMERICAN DATE TEXT PROGMEM MMDDY
48. 62 8849 62 8849 57 4925 4 36 7 84E 01 0 3 718 54 0033 54 0033 62 8849 5 7591 9 27E 01 0 1 6016 7 84 62 8849 62 8849 7 04 1 25E 00 0 1 1236 14 9733 24 9458 22 8475 8 61 1 49E 00 131 Efficiency n 0 001838884 0 004338625 0 003644317 0 009243811 0 041637706 0 080139539 0 200493194 0 164610127 0 132288869 0 09764896 0 087837891 0 023640144 Ecowatt US
49. 70 10 07 988 193770 64470 10 07 988 193770 64470 10 07 988 193770 64470 10 07 988 193770 64470 10 07 988 193770 64470 10 07 988 193770 64470 10 07 988 193770 64470 10 07 988 193770 64470 10 07 988 193770 64470 10 07 988 Capacitances Ecowatt 128 Cimin C1 Cimax C2min C2 C2max C3 CFFmin CFF CFFmax 9 00E 1 00E 1 10E 1 98E 2 20E 2 42E 1 00E 5 58E 6 20E 6 82E 06 05 05 05 05 05 07 08 08 08 9 00E 1 00E 1 10E 1 98E 2 20E 2 42E 1 00E 5 58E 6 20E 6 82E 06 05 05 05 05 05 07 08 08 08 9 00E 1 00E 1 10E 1 98E 2 20E 2 42E 1 00E 5 58E 6 20E 6 82E 06 05 05 05 05 05 07 08 08 08 9 00E 1 00E 1 10E 1 98E 2 20E 2 42E 1 00E 5 58E 6 20E 6 82E 06 05 05 05 05 05 07 08 08 08 9 00E 1 00E 1 10E 1 98E 2 20E 2 42E 1 00E 5 58E 6 20E 6 82E 06 05 05 05 05 05 07 08 08 08 9 00E 1 00E 1 10E 1 98E 2 20E 2 42E 1 00E 5 58E 6 20E 6 82E 06 05 05 05 05 05 07 08 08 08 9 00E 1 00E 1 10E 1 98E 2 20E 2 42E 1 00E 5 58E 6 20E 6 82E 06 05 05 05 05 05 07 08 08 08 9 00E 1 00E 1 10E 1 98E 2 20E 2 42E 1 00E 5 58E 6 20E 6 82E 06 05 05 05 05 05 07 08 08 08 9 00E 1 00E 1 10E 1 98E 2 20E 2 42E 1 00E 5 58E 6 20E 6 82E 06 05 05 05 05 05 07 08 08 08 9 00E 1 00E 1 10E 1 98E 2 20E 2 42E 1 00E 5 58E 6 20E 6 82E 06 05 05 05 05 05 07 08 08 08 9 00E 1 00E 1 10E 1 98E 2 20E 2 42E 1 00E 5 58E 6 20E 6 82E 06 05 05 05 05 05 07 08 08 08 9 00E 1 00E 1 10E 1 98E 2 20E 2 42E
50. 9 LCD18 LCD29 LCD28 LCD27 LCD26 LCD25 LCD24 LCD23 LCD22 LCD21 LCD 20 i1 R200 1 OR EZ B 2 Connects COLI to COL2 onthe LCD Ecowatt Port B for the enable signal to MAX1607 1 2 3 4 5 6 C400 7 o 3 100N 16V X7R GND O O vec EXT PORTB GND NOT MOUNTED Figure 30 Port B Schematic Any time an over current or short circuit condition in the circuit occurs it is necessary to disable the output so that no further damage happens to the system Therefore whenever the MAX1607 generates an over current signal the micro controller sends back a signal to the Enable pin in the MAX1607 via PBO of the AVR butterfly to disable the output As soon as the system removes the over current fault the micro controller sends another signal to re enable the output of the system Firmware The micro controller will perform the entire signal processing after receiving the inputs from its ports Then it will send the output to LCD The software does this processing The program written in C will control what the Monitor needs to do to meet the reguired condition Producing a better response reguires the proper handling of signals Fcowatt EE Voltage The voltage produced by the MFC connects to a 10 bit ADC Using the following formula will calculate the voltage Vin ADC 1024 Vref After calculating the voltage a display shows the level Table 7 Monitor Voltage Level Display after a conversion takes place
51. Chart Ecowatt Here is the snippet of the main function that controls how the logic flows As shown in the above flowchart first it checks for any circuit failure condition then it checks the optimum temperature range for MFC to operate and finally it checks the voltage of MFC Whenever the system sits idles for more than 30 seconds it goes to power save int main void Ft ff Program initalization Initialization sei mt enable interruptd char i char input for LCD puts ECOWATT 1 Delay 3000 if PINE amp 0x10 LCD_UpdateRequired TRUE 0 for if gPowerSaveTimer gt PowerSaveTimeout break LCD puts Circuit error 1 Delay 5000 LCD Clear LCD_UpdateRequired TRUE 0 char temp_err F int temp val ADC init U temp val ADC read ADCZTemp temp val Delay 3000 LCD Clear LCD UpdateRequired TRUE 0 Figure 34 Main function of Monitor Firmware Part 1 of 2 Ecowatt for temp err Temp check if temp err T if gPowerSaveTimer gt PowerSaveTimeout break LCD puts Temp out of range 1 Delay 5000 else break LCD_puts Optimum Temp 1 Delay 5000 LCD Clear LCD UpdateRequired TRUE 0 for Power check Delay 4000 if gPowerSaveTimer gt PowerSaveTimeout break gPowerSaveTimer 0 LCD puts f PSTR bye 1 Delay 3000 SMCR 2 lt lt SMO 1 lt
52. E B File Project Build Edit View Tools Debug Window Help 8x N ddu asd QW MAGE aEL gt 92 he Se OE 6 Ed I Trace Disabled R 8 de T M S M e O ua wx E mai F mt This code has only been used for debugging man co It may not be up to date Please refert to the U Object Current LCD driver code can be found in the N Add Val Bi main cof application s gcc port s2 EE za paure read only include lt avr io h gt include lt avr interrupt h gt i tinclude lt avr pgmspace h gt g TIMER COUNTER 2 finclude lt avr sleep h gt A WATCHDOG finclude lt inttypes h gt E EEPROM E finclude nain h sad SPI finclude ADC h 3 RS PORTA include lcd functions h 3j 2 PORTB include lcd driver h include timer0 h l M FORTC include RTC h RS PORTO include button h 4D ANALOG COMPARATOR 3j 32 PORTE fdefine pLCDREG test char 0xEC 3 SS PORTF 3j g amp PORTG extern uintl6 t gPowerSaveTimer External Counter from RTC c JZEJTAG uint16_t PowerSaveTimeout 30 Initial value sleep after 30 sec sB extern uintl6 t gWakeUpTimer External Counter from RTC c 3 GB EXTERNAL INTERRUPT uint16 t WakeUpTimeout 10 Initial value wake up after 10 sec v 4 B cru lt i gt L 3j Sg USI Project Processor mbler C Documents and Settings Achyut Shrestha My Documents senior design ecowatt main c 4 14 AD CONVERTER d a E BDoT LOAD Message s Y X 4 Ss USARTO Loaded plu
53. Ecowatt Figure 14 Component Cathode Body Ecowatt Figure 15 Component Support Rail Ecowatt Figure 16 Component Anode Cube Ecowatt 45 Figure 17 Component Feed Bladder Ecowatt 6 4 4 Microbial Fuel Cells Anode chamber Cathode chamber Cation selective membrane Figure 18 Schematic of Microbial Fuel Cell A microbial fuel cell Figure 18 Schematic of Microbial Fuel Cell Derek R Lovely 2006 uses the electro chemical potential difference between a donor bacterium and the final acceptor free atmospheric oxygen The bacterium gains metabolic energy by transferring electrons from an electron donor which could be any organic molecule to an electron donor A bacterium in a microbial fuel cell does not directly transfer the produced electrons to the terminal electron acceptor but are re directed to an electrode The electrode that is in contact with the bacterium is the anode The electrons are then conducted over a wire and are directly converted into electrical energy Rao et Al 1976 The electrons finish at the cathode where they are combined with protons that travel through the proton membrane and oxygen in the solution to form water Bacteria Many different possibilities for electron generation from biological species and sources have been developed Bacteria that can produce free electrons on the outside of their cell membrane are called exoelectrogenic bacteria The two main gr
54. Feed Bladder Tray are actually identical parts which improves recyclability as well as easier assembly and disassembly The Anode Cubes are arranged in an array that is only a single row deep vertically because otherwise the lower cubes would likely not receive sufficient oxygen diffusion into the water The Biobattery with enough cubes to power a USB port under current efficiencies and design fits roughly into a 2 X 2 X 3 cubic space and weighs about 500lbs when filled with water Further areas to improve on in the future would be efficiency of the electrodes implementation of Platonized electrodes to eliminate the need for a water cathode chamber and about 5596 of the weight and research into more effective fabrication methods to prevent leaks and allow for better utilization of cube surface area Specifically If the cubes could be constructed by professionals the plates could be reduced to about 2 5 on a side rather than 4 on a side drastically reducing the overall weight Ecowatt Implementation The following diagrams show the arrangement and design of the Biobattery Case Figure 9 Full Case Closed Table 6 Case Design Bill of Materials Part Number Anode Cube Small Face Big Face Support Rail Cathode Case Food Bladder Case Lid Food Bladder Ecowatt Figure 10 Case with Food Bladders Ecowatt Figure 13 Component Waste Chamber and Feed Bladder Chamber
55. In order to power a USB device a USB power switch is necessary Along with the regulation of voltage Power Management module will also monitor the system status The following diagram is a basic inflow and outflow of voltages and signals Regulated USB Power Switching Power Supply AVR Butterfly Temperature sense Figure 21 Power Management Block Diagram 6 4 7 Feeding Microbial fuel cells contain bacteria that must have a sufficient supply of food to survive In fact the power generation performance of a microbial fuel cell is dependent on food supply Since the bacteria must live in an anaerobic environment the method of adding the food to the cell solution reguires finesse Ecowatt The food supply can be added to the cell solution periodically in controlled amounts through a process called batch feeding At feeding time the solution must be maintained while the food supply is added and the waste solution is simultaneously removed Unfortunately batch feeding must be done at relatively frequent intervals and the power output can drop significantly starting about one week after last feeding To solve the problems associated with batch feeding researchers have employed continuous feeding Continuous feeding maintains a steady flow of food supply into the cell and an equal flow of waste solution out of the microbial fuel cell requiring little maintenance or upkeep On the other hand continuous feeding systems are com
56. Increase verbosity level Please use this when submitting bug reports about avrdude See lt http savannah nongnu org projects av rdude gt to submit bug reports AVRDUDE FLAGS v v Define directories if needed DIRAVR c winavr DIRAVRBIN DIRAVR bin DIRAVRUTILS DIRAVR utils bin DIRINC DIRLIB S DIRAVR avr lib Define programs and commands SHELL sh CC avr gcc OBJCOPY avr objcopy OBJDUMP avr objdump SIZE avr size 120 Programming support using avrdude AVRDUDE avrdude REMOVE rm COPY cp HEXSIZE SIZE target FORMAT TARGET hex mt use hexadezimal output fromat org ELFSIZE S SIZE A TARGET elf ELFSIZE SIZE x A TARGET elf Define Messages English SG ERRORS NONE Errors none SG BEGIN begin SG END Fi end SG SIZE BEFORE Size before SG SIZE AFTER Size after SG COFF Converting to AVR COFF SG EXTENDED COFF Converting to AVR Extended COFF SG FLASH Creating load file for Flash SG EEPRO Creating load file for EEPROM SG EXTENDED LISTING Creating Extended Listing SG SYMBOL TABLE Creating Symbol Table SG LINKING Linking SG COMPILING Compiling SG ASSEMBLING Assembling SG CLEANING Cleaning project Define all object files OBJ SRC c o ASRC S o
57. Isolated pure cultures are more readily analyzable and reliably attainable The pure cultures refer to the cultures or growth of bacteria having only one species present These pure cultures have been gained by selectively growing a certain species from a mixed culture and testing only that one species Many environments support these free electron producing bacteria In fresh water environments the bacteria Geothrix contributes to electricity production Desulfobulbus produces free electrons in the presence of sulfur Rhodospirillum rubrum generates electricity when exposed to ultraviolet light in an anaerobic environment Many iron reducing bacteria have been discovered These include Geobacter hydrogenophilus Geobacter sulfurreducens Geobacter chapelleii Geobacter Metallireducens and others This species of free electron producing bacteria are commonly referred to as the Geobacter Geobacter was first described by Lovely et al on November 19 1987 Geobacter Metallireducens was the first bacterium that was discovered to completely oxidize multi carbon organic compounds with the reduction of iron Lovely 1987 The bacterium Geobacter Metallireducens was chosen from the other possible species explained in the research section because of three reasons Geobacter has the largest power generation to electrode surface area of all researched species Geobacter also is one of the most established and proven species for consistent power generation
58. K KKK KK KKK KKK KKK KR KKK ok kk kk dk ck ck ckck KKK KKK KK KK KK KK KKKKKK KK kk ck kk Function name CHAR2BCD3 Returns Binary coded decimal value of the input 3 digits Parameters Value between 0 255 to be encoded into BCD Ecowatt Purpose Convert a character into a BCD encoded character The input must be in the range 0 to 255 The result is an integer where the thr lowest nibbles contain the ones tens and hundreds of the input ck ck ck ck ck kk kk kk AA AA KK A AAA AA KK AKA A KA ko ko KK kk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk unsigned int CHAR2BCD3 char input int high 0 while input gt 100 Count hundreds high input 100 high lt lt 4 while input gt 10 Count tens high input 10 return high 4 input Add ones and return answer KRAKK KKK KK KKK KKK KKK KK KKK KKK KKK k ck ck ck ck ck kk kk kk AA KA KK A AAA KA KK AKA A KA ko ko K hh Function name LCD Init gt Returns None Parameters None Initialize Purpose LCD displayData buffer Set up the LCD timing contrast etc kkkkkxkxkxkxkxkxkkkxkxkxkxkxkxkxkxkkkkkxkxkxkxkxkkkkxkkkkxk kxxk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk void LCD Init void LCD AllSegments FALSE Clear segment buffer LCD CONTRAST LEVEL LCD INITIAL CONTRAST Set the LCD contrast level 110 Selec
59. L Initialize countdown timers for i 0 i lt TIMERO NUM COUNTDOWNTIMERS i CountDownTimers i 255 Initialize Timer0 Used to give the correct time delays in the song Enable timer0 compare interrupt TIMSKO 1 OCIEO0A Sets the compare value for 10ms delay ifdef OSC ALT OCROA 35 t0 is at 3600kHz else OCROA 38 t0 is 3900kHz fendif Set Clear on Timer Compare CTC mode CLK 256 prescaler TCCROA 1 lt lt WGM01 O lt lt WGMOO 4 lt lt CS00 1Mhz Clk Set Clear on Timer Compare CTC mode CLK 1024 prescaler TCCROA 1 lt lt WGM01 O lt lt WGMOO 5 CS00 4Mhz Clk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk ck ck ck ck ck kk kk kk kk KA AKA AAA AA KK AKA A KA ko ko e hh Function name TIMERO COMP interrupt Returns None Parameters None Purpose Check if any functions are to be called ck ck ck ck ck kk kk ck kk ck AA KK A AAA KA KK AKA k KA ko ko e w w kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk mtA pragma vector TIMERO COMP vect _ interrupt void TIMERO COMP interrupt void SIGNAL SIG OUTPUT COMPAREO mtl ti E mt char i uint8 t i Ecowatt f r i 0 i i lt TIMERO NUM CALLBACKS if CallbackFunc i NULL CallbackFunc i Count down timers for i 0 i lt TIMERO NUM COUNTDOWNTIMERS i l TF CountDownTimers i
60. MAX1522 MAX1523 MAX1524 Simple SOT23 Boost Controllers 2001 Maxim Integrated Products 23 Apr 2008 lt http www maxim ic com quick_view2 cfm qv_pk 2451 gt Ecowatt MA3ZD12 Datasheet Digi Key Apr 2004 Panasonic SSG 23 Apr 2008 lt http search digikey com scripts DkSearch dksus dll Detail name MA3ZD1200LCT ND gt Rabaey K Lissens G Siciliano S D Verstraete W A microbial fuel cell capable of converting glucose to electricity at high rate and efficiency Biotechnology Letters 25 1531 1535 2003 Simpson Chester Linear and Switching Voltage Regulator Fundamentals National Semiconductor National Semiconductor 6 Dec 2007 lt http www national com appinfo power files f4 pdf gt TPS62100 datasheet DatasheetCatalog com Dec 2000 6 Dec 2007 lt http www datasheetcatalog com datasheets pdf T P S 6 TPS62100 shtml gt Path Go to the website link and click on TPS62100 datasheet in middle of the screen to the right Underwriters Laboratories Inc UL 5 Dec 2007 lt http www ul com gt Wuidart L TOPOLOGIES FOR SWITCHED MODE POWER SUPPLIES STMicroelectronics 1999 STMicroelectronics 6 Dec 2007 lt http www st com stonline books pdf docs 3721 pdf gt Ecowatt 10 Appendices 10 1 Appendix I Biobattery Assembly Instructions sseses aaa aaa anna aaa aa aaa eaaaaaaaaca 84 10 2 Appendix II Bladder Filling Procedure sssuea soo ea aa aaa aaa aaa
61. Palod 71915043 014 Tausqampaford 1ue3 nsuo JELYSNPUI 105 aug Palod JUPYNSUOD EL SNPUJ 105 Jag 21Eda1g Sddd H4210 ausgamp3f01d T 491504 Polold T uone1ussa4d E40 supno Sddd sapo noo 3 tpjessag poloigsujsg sue4quie AJ UD IE2SZY Sunsa J 7 yrmog enapeg au pea enapeg enapeg LUDIEDSDY Wea auyag Gantt Chart of Fall Semester Actual 4 igure F 0 280 0T L0 oN 8C LO AON PT 0 BO TE LODO LT L0 0 L0 da5 6T L0 das g 3 o o Lu 80 RA OT 80 1dv 0 80 1dy 07 80 1dy 0T 80 1EIA TE 80 1EIN TC 80 1EIA TT ppo ejdsig sjno puew 13 sod dmas sjuauoduioo Aejdsip AJ uep JYSIN USISIG 101UBS uoneiuasaJg eur Aq 143JUOJ JEULIOJ Zur 3202844 Ajaanesayy maay uonejuasald GNI sudei3 pue sapis dojarag SUING d1eda1g uoneiuasaJg jeur IPO Ado jeur4 3ruqns HPI JUaLUNIOp ayua M3IADY JUIUWINJOP 3U0 ozu JUILUI0 suonpas ENPIAMPUI Malay suipno JUOdayppnnsuo JModay eut4 21e dad 1ue3 nsuoo EL SNPUJ tr Jaa A uonejuasaJg Aq uonejuasaidg a 1edaag JUEJ NSU07 M 8344 puz 104 3 je dag 80 1EIA T Figure 5 Gantt Chart of Spring Semester Plan Ecowatt Project Milestones In the beginning of the Fall 2007 semester there were few milestones identified that would keep on track the scope and the schedule of the project The time line for the fall semester schedule was used to identify these milestones The milestones that would be achi
62. R ohm V v I A I mA P mW 10 0 0001 0 00001 0 01 0 000001 100 0 0007 0 000007 0 007 0 0000049 1000 0 007 0 000007 0 007 0 000049 10000 0 059 0 0000059 0 0059 0 0003481 100000 0 204 0 00000204 0 00204 0 00041616 1000000 0 273 0 000000273 0 000273 0 000074529 Ecowatt 12 03 07 R ohm V v IA I mA P mW 10 0 0 0 0 100 0 001 0 00001 0 01 0 00001 1000 0 011 0 000011 0 011 0 000121 10000 0 082 0 0000082 0 0082 0 0006724 100000 0 235 0 00000235 0 00235 0 00055225 1000000 0 293 0 000000293 0 000293 0 000085849 12 04 07 R ohm V v IA I mA P mW 10 0 0001 0 00001 0 01 0 000001 100 0 001 0 00001 0 01 0 00001 1000 0 012 0 000012 0 012 0 000144 10000 0 093 0 0000093 0 0093 0 0008649 100000 0 268 0 00000268 0 00268 0 0007182 1000000 0 333 0 000000333 0 000333 0 0001109 12 05 07 R ohm V v IA mA P mW 10 0 0 0 0 100 0 0002 0 000002 0 002 0 0000004 1000 0 001 0 000001 0 001 0 000001 10000 0 008 0 0000008 0 0008 0 0000064 100000 0 019 0 00000019 0 00019 0 00000361 1000000 0 021 0 000000021 0 000021 0 000000441 12 06 07 R ohm V v IA I mA P mW 10 0 0001 0 00001 0 01 0 000001 100 0 0005 0 000005 0 005 0 0000025 1000 0 005 0 000005 0 005 0 000025 10000 0 046 0 0000046 0 0046 0 0002116 10
63. SE char Timer0 AllocateCountdownTimer mt char i uint8 t i for i 0 i lt TIMERO NUM COUNTDOWNTIMERS i if CountDownTimers i 255 CountDownTimers i 0 return i l return 0 void Timer0 SetCountdownTimer char timer char value cli mt disable interrupt CountDownTimers timer 1 value sei mt enable interrupt char Timer0 GetCountdownTimer char timer char t Ecowatt cli mt disable interrupt t CountDownTimers timer 1 sei mt enable interrupt return t void Timer0 ReleaseCountdownTimer char timer cli mt disable interrupt CountDownTimers timer 1 255 sei mt enable interrupt main h kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk ck ck ck ck ck Ck Ck kk ck ck ck ck AA AKA AAA KA KK ck ko kc k kc ko KA hh w File main h Author s Achyut Shrestha Target s ATmegal69 Compiler AVR GCC 3 3 1 avr libc 1 2 Description AVR Butterfly main routines Revisions 1 0 YYYYMMDD VER COMMENT SIGN 20080503 main routine Achyut Shrestha J KR KK KKK Ck kk kk kk kk kk kk Kok KKK kk ek kk e ke k kk kk ck ck ck ck AA KAZ ck ck ck K KA AA AK KA KA ck ck ckck ck ck KK define BOOL char define FALSE 0 116 define TRUE FALSE define NULL 0 define AUTO 3 define BV bit
64. Semester Ecowatt met to again to analyze the team s adherence to the predetermined schedule which was not as close to the plan as the team had hoped Output regulation redesigns postponed the ordering of parts until later in the semester and the Biobattery construction membrane and electrode assemblies especially proved more tedious and time consuming than anticipated Cost effective gold wire was also particularly difficult to acquire All in all the team met the course established deadlines as well as many of the additional deadlines set up at the end of the Fall 2007 semester being constantly driven by an ambitious planned Gantt Chart m N Ecowatt L029 CI LO AON 8T LO AON FT LO PO TE Sddd eut q uonequasaJq P0 uoispag pue Sunsa sapo 23 3 padsy uonduinsuo mod YDJLISIY u31s2q amour Jepus YDILISIY xea1g SUMES UEY 310N 1421504 Palo Tausqampaford jue3insuo ELYSNPU 104 ja Palod Sddd eig ayusqa mMm 129fo4g T 4291504 Dalo1g T uonejuasaJq 210 2upno 3dd sapo n 9 3 tpaessay pefo4g auyeg UPA A ueasa L0 P0 LT 0 P0 L0 das GT PLDJILY tpaeasay Wea ougag L0 das Figure 3 Gantt Chart of Fall Semester Plan E N Ecowatt Sddd Eut4 7 UOHPIUJSDU PAO uoispag pue 3unsa s3po na g padsy uonduinsuo amod YDLISIY u31s2 JINAN Jejus YDILISIY Taueyynsuoz er snpu 104 jag
65. TRUE the interRC is correct TCCRIB 1 lt lt CS10 start timerl kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk ok kk kk dk hg KA KA A K A AZ KAZ A ZAK KA ZA K AA kckckck KKK Function name Delay Returns None Parameters unsigned int millisec m Purpose Delay loop based on a 1Mhz Clock ck ck ck ck ck ck ck ck ck ck ck ck ck ck ck AA ck ck X A ck ck AX X ck ck k ck ko Sk ko ko ko ko ko kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk void Delay unsigned int millisec mt int i did not work in the simulator int i uint8 t i while millisec mt for i 0 i lt 125 i for i 0 i lt 125 i asm volatile nop fk kk kk KKK KK KKK KKK KR kk KK KKK KKK KR KKK kk ck ck ck ck ck ck kk ck kk ck AKA KK A AAA KA KK ck ko k A kc ko ko ko K hh B Function name ADC init 104 Returns None Parameters char input ox Purpose Initialize the ADC with the selected ADC channel Ckckckckckck dk hg KA KA AK A AK KAZ A AXA K KA ZA AA KA kck KKK kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk void ADC init char input ADMUX input external AREF and ADCx ADCSRA 1 lt lt ADEN 1 lt lt ADPS1 1 lt lt ADPSO set ADC prescaler to 1MHz 8 125kHz input ADC read dummy kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk ck ck ck kk kk kk ck kk ck KAZ KK A AAA kk KK AKA A KA e ko e hh Function name ADC read
66. Test Results Voltages on the MAX1524 Vin Vout VGND VFB VSET VSHDN VEXT Vcc 0 25 0 187 0 0 0 0 25 0 0 25 0 5 0 437 0 0 0 0 5 0 0 5 0 75 0 625 0 0 0 0 75 0 0 75 1 1 12 0 0 437 0 1 1 1 1 25 2 62 0 1 37 0 1 12 1 12 1 12 1 5 4 37 0 2 5 0 1 25 1 25 1 25 1 75 7 93 0 3 56 0 1 31 1 37 1 31 2 7 93 0 1 68 0 1 37 1 37 1 37 2 25 7 93 0 5 0 1 37 1 37 1 37 2 5 7 93 0 7 93 0 1 43 1 43 1 43 2 75 7 93 0 7 0 1 43 1 43 1 43 3 5 0 2 18 0 1 06 1 06 1 06 R lout 988 4 82 5047 4 93 10886 1 25 50360 1 25 98800 1 25 520000 1 25 977000 1 25 Ecowatt P Resistor Capacitor Inductor Voltages Voltages Voltage VR1 VR2 VR3 Vc1 Vc2 Vc3 VCFF VL1 0 187 0 0 25 0 25 0 187 0 25 0 187 0 25 0 437 0 0 5 0 5 0 437 0 5 0 437 0 5 0 625 0 187 0 75 0 75 0 625 0 75 0 625 0 75 1 12 0 437 1 1 1 12 1 1 12 1 2 62 1 37 1 25 1 25 2 62 1 0 875 1 25 4 25 2 5 1 5 1 5 4 31 1 18 1 93 1 56 6 6 4 1 87 1 75 7 93 1 31 3 25 1 75 7 93 6 81 2 08 2 7 93 1 37 4 75 2 7 93 5 2 12 2 18 7 93 1 37 7 93 2 7 93 7 93 2 5 2 43 7 93 1 43 7 93 2 43 7 93 7 12 2 62 2 5 7 93 1 5 7 93 2 56 3 37 2 12 3 3 4 93 1 06 4 93 2 87 MOSFET Voltages Diode Voltages Vais Vaic VQ1D VD1in VD1out 0 0 0 25 0 25 0 187 0 0 0 5 0 5 0 437 0 0 0 75 0 75 0 625 0 1 1 25 1 25 1 12 0 1 12 2 87 2 68 2 62 0 1 25 4 37 4 5 4 37 0 1 37 5 43 5 31 4 81 0 1 37 5 93 5 87 5 18 0 1 37 7 93 7 93 7 25 0 1 43 7 93 7 93 7 93 0 1 43 7 7 93 7 93 0 1 06 3 81 5 06 4 75 Ecowatt 16
67. Wolfe s Vitamin Solution b Using a syringe and needle add 0 64mL of Wolfe s Mineral Solution Ecowatt 10 3 Appendix III MFC Testing Data mL Media Concentration Sodium Acetate First Setup 10mL 082 mol L Second Setup 10mL 082 mol L First setup voltage measurements Date 4 Day OCV v A Rint ohm 11 19 2007 0 0 63 11 20 2007 1 0 3 0 00002 14900 11 24 2007 5 0 3 0 00002 14900 11 26 2007 7 0 26 0 00001 25900 average 18566 67 Second setup voltage measurements Date Hhrs OCV v A Rint ohm 11 27 07 4 30 PM 0 0 2 0 000034 4882 352941 11 28 07 9 00AM 16 5 0 314 0 000011 27545 45455 11 28 07 1 30PM 21 0 323 0 000021 14380 95238 11 29 07 8 00 AM 39 5 0 308 0 000008 37500 11 29 07 4 30PM 48 0 335 0 0000081 40358 02469 11 30 07 2 00PM 69 5 0 289 0 000007 40285 71429 12 1 07 10 00AM 89 5 0 281 0 000007 39142 85714 12 3 07 8 00 AM 135 5 0 287 0 000011 25090 90909 12 4 07 8 00 AM 159 5 0 339 0 000012 27250 12 5 07 9 00 AM 184 5 0 159 0 000001 158000 12 6 07 8 00 AM 207 5 0 28 0 000005 55000 average 42676 0241 Ecowatt First setup measured and calculated parameters Fcowatt IEEE 11 20 07 R ohm V v I A I mA P W P mW 10 0 0 0 0 0 100 0 002 0 00002 0
68. Y const char CANADIAN DATE TEXT PROGMEM YYMMDD mtE different date formates table for putting DD MM and YY at the right place on the LCD const uint8 t EUROPEAN DATE NR PROGMEM Ay 5 2 3 O f const uint8 t AMERICAN DATE NR PROGMEM AS Do Oi dg By Bo he const uint8 t CANADIAN DATE NR PROGMEM Qs Ly Dy 3p 4 Body PGM P DATEFORMAT TEXT EUROPEAN DATE TEXT AMERICAN DATE TEXT CANADIAN DATE TEXT TIMER CALLBACK FUNC CallbackFunc TIMERO NUM CALLBACKS uint8 t CountDownTimers TIMERO NUM COUNTDOWNTIM ERS kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kk ck ck ck kk kk ck kk ck Ck Ck KK A AAA AKA KK AKA A KA ko ko e w w Function name main Returns None B Parameters None x Purpose Contains the main loop of the program ck kk kk dk e KA KA A K A AZ KAZ A X AK KA ZA AA kckckck KKK kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk int main void Program initalization Initialization sei mt enable interrupt char i char input for LCD puts ECOWATT 1 Delay 3000 Ecowatt if PINE amp Ox10 LCD UpdateRequired TRUE 0 for 77 if PowerSaveTimeout gPowerSaveTimer gt break LCD puts Circuit error 1 Delay 5000 LCD Clear LCD UpdateRequired TRUE 0 char temp_err F int temp val ADC init 0 temp val ADC read
69. above the level that the Geobacter can keep up with the performance of the bio battery will degrade significantly Therefore the system needs protection from an over current withdrawal by a load Using a fuse can help regulate the current being drawn from the system Whenever an overload happens the fuse will break stopping the flow of current The user will then need to replace the fuse Another way to protect from the over current condition is to implement a circuit that will detect the current limit reached and shut off the power provided to the load Once the user removes the load the Biobattery will function normally without having to change any component Decision An analog system is comparatively easier to implement in order to monitor the system status It will also not consume any power from the MFC which is the biggest advantage The disadvantages in using a analog method is that it is not very user friendly especially when the user will have to use some form of judgment to monitor the system The user will not need to read various measurements and act on it Each of the measuring units is individual which will increase the cost of the system It is aesthetically unpleasing as well One major problem is the use of thermometer since it will contain mercury The product designed has to be environmentally friendly and the use of mercury goes against this In addition the replacement of a fuse every time the system overloads does not to
70. aee ek nak sk 67 Figure 33 Monitor Flow CHAN c zzsde e soauiadeaesstoduuddaoek aasaiacdbadu dat aosaiudaujd 69 Figure 34 Main function of Monitor Firmware Part 1 of 2 lt lt lt 70 Figure 35 Main function of Monitor Firmware Part 2 of 2 lt lt lt 71 Figure 36 Input Voltage vs Output Voltage rasnnrrenrannnnvnnrnennvnnnsennrrvesennnrnsenennrnnnsennrsenssnnnnenee 76 Ecowatt Figure 37 Input Current vs Output Current 2 2 20 eee eee eee eee eee eee eee eee nenene nene nene eee nn 76 Figure 38 Input Power vs Output Power o ee eee 000000000 eee eee eee eee Ree aaa ae ee Renee nene 77 Figure 39 Efficiency with Variable Input Voltage seesues aso enne nnne 77 Figure 40 Load Resistance vs Output Current eeeeeaa eee enea aaa aaa aaa aaa aa oaza aaa ae ena neon n 78 Figure 41 AVR Studio 4 IDE 96 Fig re ETG a A AA AA Fi Ea 97 Figure 43 ATMega169 Schematic oai kia EE aa AGGA 99 Table of Tables Table 1 Abbreviated TST MS aaa aw OEG 11 Table 2 Chemical Concentration in Feed aeaannvnnnanvnananvnnnnnvnnnnnvnnnnnnnnnnnnnnnnnnnsnnnnnnnnnnnnsnnsvnenene 17 Table 3 Team Member RO ES s ao GW AO A Gia 21 Table 4 Fall 2007 Major Milestones and Dates Accomplished eeu aaaeuaaaa r 26 Table 5 Spring 2008 Major Milestones and Dates Accomplished eee 26 Table 6 Case Design
71. ally works EN Design Research Figure 1 Method of Approach Although the approach seems linear the phases overlap Figure 1 Method of Approach The implementation will not always work as designed or planned so we need to go back to our design and readjust the changes Sometimes we might even have to go back to our research and find out what we overlooked Many times design has to be revised based on new findings and researching so we are constantly changing design for improvement so the approach is actually cyclic 5 3 Safety and Environmental Impact There are consequences to our actions that impact environment sometimes negative even unintentional Many products in the market claim to be green but are produced and manufactured without the environment in consideration So not only a product should be environmentally friendly but it is also preferable that the environment itself where the product is made be green So the other aspect of our design is to ensure that the process used for making MFC itself does not impact the environment in negative ways This means that the methodology used also must have minimal and positive effects on the environment Equally important is the safety of the device and anyone who is operating the device One way to ensure safety is providing appropriate labels for caution and warning However the more effective way is to educate a user about the correct usage of product Safety must also be practice
72. ck kk AKA AAA AA KK A AAA ZA KK AKA A KA ko ko e hh A Function name RTC init returns none i parameters none Purpose Start Timer Counter2 in asynchronous operation using a 32 768kHz crystal kkkkkkkkkkkkkikkkkkkkwkkkikkiikkkwkkwwikkkkwwkk ck e kk kk ke AA AA KA KK A ZA A KA KA AKA AZ kckckck wh ck kk void RTC init void Delay 1000 wait for 1 sec to let the Xtal stabilize after a power on cli disable global interrupt cbi TIMSK2 TOIE2 disable OCIE2A and TOIE2 ASSR 1 A82 select asynchronous operation of Timer2 TCNT2 0 clear TCNT2A TCCR2A 1 CS22 1 CS20 select precaler 32 768 kHz 128 1 sec between each overflow while ASSR amp 0x01 ASSR amp 0x04 wait for TCN2UB and TCR2UB to be cleared TIFR2 OxFF clear interrupt flags Sbi TIMSK2 TOIE2 enable Timer2 overflow interrupt sei enable global interrupt 113 initial time and date setting gSECOND 0 gMINUTE 0 gHOUR 12 mt release timestamp gDAY 16 gMONTH 10 gYEAR 3 kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk ck ck ck kk kk ck kk ck KA KK AA AA ZA KK AKA A KA KKK kck hh Timer Counter2 Overflow Interrupt Routine Purpose Increment th real tim clock The interrupt occurs once a second running from the 32kHz crystal This routine remains active during the Powe
73. criterion for having a simulation file Even though this result is regrettable Ecowatt will still simulate the circuit through testing The circuit went onto the board for soldering without any computer analysis beforehand Little to no error is tolerable because no simulation is possible To offset any problems extra caution planning and careful calculations were necessary Ecowatt Calculations All calculations and procedures necessary for the design of the regulator came from the MAX1524 datasheet provided by Maxim Integrated Products Mathcad did all the calculations performed to ensure correct values as shown in the appendix The set of calculations used come from the discontinuous conduction mode DCM portion of the datasheet in addition to the section for setting the output voltage and calculating the maximum duty cycle 6 Vinmin 25V tonmin 0510 9 Vout 5V oadmax mA VD 05V Ipeak lA lout 500m tss 3 2ms VFB 125V Ry 65k Ry 0050 Ly 380 10 H Vimar 337 typmer 05x10 7s Vin 3V L 1 380 C 12 10 F Q 11x 10 out g7 load 300mA Setting the Output Voltage Finding the Maximum Duty Cycle V V p Vn out out D inmin Ry Ry v 1 DutyCyclepq as s Ry 4 FB out D a 4875x10 Q Calculating the Peak Inductor Current Selecting an Inductor E 2 115 V out YD 3310 2 22 66 x 10 IPEAK p lloadmas CNN in Oruturi Y 6 1 3340 66 x 10 396 x 10 LN OSAA Ry
74. d Analysis c sccccsssscecessseeeeeeeeaeeeeeees 72 CEN AN Ir EE NE 73 6 5 1 MONITO et 73 6 5 2 BEGLIBSION Mew GA 74 Fa HUI TT 79 TL Lessons Lom cm 79 FA MEE D UA Gai A OE ERO c dA 79 B Acknowledgements GO Ga adu radou kaz k R dl a B o E 80 EE REIETEMCES EE a dada cat en A Valeo a 81 10 ADDE AIEOS ztuzeduduiiai ela dtss e adaidkieutiuudaetalladiouolsteatd k akdo dwa e doda Ur deis 83 Ecowatt 10 1 Appendix I Biobattery Assembly Instructions ssssee aa aaa aaa aaa aaa aaa aeeaaaaaaacca 84 10 2 Appendix II Bladder Filling Procedure sese 87 10 3 Appendix III MFC Testing Data is eee zad dA 88 10 4 Appendix IV Product Information Sheet of ATBE Sn 93 10 5 Appendix V Membrane Testing Data eses eee a oe ea aa aaa aaa aaa ae nnne nnne 94 10 6 Appendix VI Nafion 117 Information sheet ssesuaaa oe a aaa aaa aaa eeaaaaaaaaca 95 10 7 Appendix VII Software TOONS az l R ed ed R 96 10 8 Appendix VIII ATMega169 Specifications eeeuuo ooo aaa aaa aaa aaa aaa aaa ae eaaaaaaaaca 98 Ur MIU c Pla alek w de Kop bananene 98 VEL SENEMOUEG A GAGA GOA GER A AZ A 99 10 9 Appendix IX Monitor Source Code Written in C 100 10 10 Appendix X Regulator Test Results rrsnnrrrnrannnnvnrnnennvnnresnnrrvnsensvnenssnsnnvnnssennrsen
75. d Water System also includes design of the MFC chambers and a Tank Refilling Station The Output Regulator will ensure a stable power output at standard battery voltage and consistent current whenever the MFC is functioning A MFC Monitoring System will communicate to a user by relaying important information such as the voltage level of the MFC and feeding time for Geobacter Ecowatt 3 3 Project Requirement and Criteria There are minimum requirements that must be fulfilled in order to meet the objectives of the project So the design must meet following criteria for this project to be successful e The microbial fuel cell array must provide at least 5 volts e The user must be able to feed the Geobacter without any unreasonable difficulty e There must be a feed indicator for letting the user know that it is time to feed Geobacter e The circuit implemented for monitoring and regulating the voltage must use minimum possible power from the MFCs e n case the circuit fails the Biobattery should still provide a voltage output and also let user know about the failure e The Biobattery case must protect the Biobattery contents from the outside world and protect the outside world from the Biobattery contents e The terminals from the Biobattery must be easily accessible for a user to power a device e The circuit must protect itself and the connected device from any voltage spikes so it must provide a stable voltage and not cause any dama
76. d above are not part of the estimate for the construction of the Biobattery prototype 6 4 Design The MFC system can be divided into three sub systems namely the fuel cell MFC monitor and Output Regulator The figure below is a basic block diagram of the overall system The figure below Figure 6 System Interaction shows the interaction between the MFC and the power management systems Power Management Figure 6 System Interaction 6 4 1 Anode Cube Current research has not been particularly focused on volumetric power density but this is a critical factor in the viability of a Biobattery as a realistic power source In response to this Ecowatt worked to design a new cell arrangement that drastically improves upon the existing configurations the Anode Cube Ecowatt Design Considerations Criteria The Anode Cube design had several criteria to meet The new cell arrangement must easily facilitate the feeding process of many cells simultaneously but not all cells can share an Anodic Solution due to the electrical combination of voltages Basically in order to add voltages cells must not share an Anodic Solution they can however sum current even while using a shared Anodic Solution The size of each electrode must be sufficient to provide meaningful power yet small enough to combine in a space efficient manner and the final design must be buildable on a prototype and production scale Design Alternatives Analysis Se
77. d monitoring to let the user know when it is time to change the feedstock as well as remove the waste from the system Sensors such as level or pressure sensors are attachable to the feed and waste which will tell the user to take some action when the feedstock is low or the waste needs draining The signals generated by the sensors will need processing hence also requiring power from some source which is the MFC in this case Another way to monitor the feed and waste levels is simply to use clear transparent feed and waste level A user can easily replace the feed when the feedstock stored in a clear bag is about to go empty Similarly filling a small sized glass ring when the waste level rises to a certain level will tell the user the waste is about full and needs draining Temperature The temperature of its environment heavily influences the feeding behavior of Geobacter The optimum temperature range is 20 35 Celsius for activity of these bacteria The temperature beyond these ranges will not produce the required voltages The user needs to know when the temperature is not within the range Implementing an analog thermometer gauged to a predetermined reading can work for this purpose The alternative is to use a Ecowatt temperature sensor which will require some signal processing and will consume power in order to do so Current The Biobattery can only produce so much current to provide for a load When the load starts to draw current
78. d sufficiently strong material while being as recyclable as possible it should fit into a one meter cube For the Feeding System to work the Feed Bladders must be stored above the Cathode Tank and the Water Tank must be below the Cathode Tank The Feed Bladders need to be stored in an accessible location and the Water Tank needs to be accessible for emptying Design Alternatives Analysis Many materials were considered for the case design but the specifications are very specific Metal is ideal for recyclability but the density is much higher than alternative plastics Wood is attractive strong cheap and available but once again the weight is a critical factor Also wood is not ideal for storing water solutions Decision The Case will be made almost entirely out of clear polycarbonate PC On the front of the Cathode Tank will be mounted a panel containing the Monitoring System LCD display and concealing the circuitry PC has optimum strength to weight ratio for holding a large amount of water while not adding significantly to the weight of the Biobattery It is easily manufactured as clear allowing for a passive monitoring of the system by the user Basically the user can see when the feed bladders are empty and when the water tank is nearly full The Case Design is a modular one with as many similar parts as possible The design follows a stacked form factor with consistent length and width in stacked trays The Water Tank and
79. d while producing the product itself Still the safety of the MFC must also be considered so that foreign objects do not intrude into the system causing inadvertent effects Ecowatt 5 3 1 Electrical Impact The safety and environment is of utmost concern for the electrical components used in the system The components used must be RoHS compliant and lead free The electrical device is one of the hardest materials to recycle They also have a massive carbon footprint Since the size of the components matter using surface mount parts to reduce the carbon footprint as much as possible is important Electrical devices are also power hungry Whenever any component is not in use it is better to turn it off or at least leave it in an idle state so the power consumption decreases dramatically When the lifetime of an electrical device is over some components still are reusable Recycling printed circuit boards can also go to extract the metal present in them However recycling electrical parts are expensive The safety of electrical devices needs great care especially when these operate near a moist environment Any liquid spill can cause the circuit to malfunction which will lead to replacing the part In order to avoid unintentional accidents the electrical components need careful packaging so no foreign material can destroy the parts Therefore a robust design will take safety and environment concerns in mind and prevent any forcible accidents The de
80. e avr libc not yet described there Wa adhlns S 1st docs FIXME ASFLAGS gstabs Optional linker flags Wl tell GCC to pass this to linker Map create map file cref add cross reference to map file LDFLAGS Wl Map TARGET map cref Additional libraries Minimalistic printf version LDFLAGS Wl u vfprintf lprintf min Floating point printf version requires lm below LDFLAGS Wl u vfprintf lprintf flt lm math library LDFLAGS 1m Programming support using avrdude Settings and variables Programming hardware alf avr910 avrisp bascom bsd dt006 pavr picoweb pony stk200 sp12 stk200 stk500 Ecowatt Type avrdude c to get a full listing AVRDUDE PROGRAMMER stk500 AVRDUDE PORT coml programmer connected to serial devic HAVRDUDE PORT lptl programmer connected to parallel port AVRDUDE WRITE FLASH U flash w TARGET hex AVRDUDE WRITE EEPROM U eeprom w TARGET eep AVRDUDE FLAGS p MCU P AVRDUDE_PORT AVRDUDE PROGRAMMER Uncomment the following if you want avrdude s erase cycle counter Note that this counter needs to be initialized first using Yn see avrdude manual AVRDUDE ERASE y Uncomment the following if you do not wish a verification to be performed after programming the device AVRDUDE FLAGS V
81. e can test how the voltage regulator responds in terms of voltage and current Another important aspect of testing is the amount of power dissipated by the circuit While this measure relates to the circuit s Ecowatt current load efficiency power dissipation gives a better idea of how much power the circuit uses in terms of actual numbers not a percentage like the current load efficiency In addition the current load efficiency is dependent on a varied current load while the power dissipation seeks the maximum amount of power consumed by the circuit Testing the current and voltage occurred at all pins in order to understand how the circuit works and if it works for that matter Given time constraints not all of these values became available for testing However with the exception of varying the load for any given input all values became available during testing Testing was accomplished using a LeCroy WaveJet 322 Oscilloscope two LeCroy PPO10 cables one Graymark Model 803 Solid State Power Supply two Heath Built Model EUW 30 resistor boxes Pomona Electronics connectors and M Deller alligator clips Attaching the circuit to the power supply and oscilloscope one varied the voltage by increments of 0 25V to 3 0V Using the resistor boxes the power that the resistors were capable of handling increased from a quarter of a Watt to one Watt Yet to increase the voltage much beyond 3V will cause the resistors to burn out To prevent this from hap
82. e make her an invaluable resource for Ecowatt She has worked at DC Cook Nuclear Power Plant in Bridgman MI and for a company that specializes in sensors for space Blue Line Engineering in Colorado Springs CO Her passion for renewable and alternative energy sources has stemmed from her internship in the nuclear field and grown through her research and further study on the Biobattery She is enjoying seeing her contributions become actualized in a final product or prototype Jared Huffman BSE MECH ELEC BA PHIL Jared is a fifth year senior engineering student BSE with a split concentration between the electrical and computer concentration and the mechanical concentration at Calvin College He will also be achieving a BA in Philosophy from Calvin College at the same time He has held a couple of different internships over the years with the most recent opportunity being a position at Kellogg Company in Grand Rapids MI he has worked full time during the summer months and part time during the school year His favorite Engineering subjects are Industrial Processes and Technical Writing his course work in the Philosophy department has enabled him to develop a keen analytical sense as well as creative problem solving skills He grew up mostly in Lowell MI in a family of seven with two brothers and two sisters his passion for Project Management originated with the large family unit and extended into frequent leadership positions in various clubs and
83. e vitamin lot number being 57954988 and the mineral lot number being 57954994 These materials came on November 5 2007 which is 13 days after ordering The individual battery cost for bacteria will be highly dependent on the final number of MFCs produced 6 3 Business Plan for Full Scale Production of Product The Biobattery project as presented is not quite ready for commercial consideration so a production level economic analysis is not currently possible The future feasible of the Biobattery as a viable product is discussed at length in other sections of the Design Report The only recommendation the team can make at this time would be to follow the established decision making processes and core fundamental values of Ecowatt in designing a full scale production process that provides a good environment for workers efficiently produces the product and generates a minimal negative impact on the surrounding local and global environment 6 3 1 Marketing Because the resulting cost of each unit will go beyond the means of what most consumers will want for a battery the bio battery will sell strongest among those concerned about the environment Therefore marketing will focus on those willing to pay the price in their cause of good stewardship of the environment In addition marketing will show that this device will demonstrate that the bio battery is a viable alternative fuel to regular lead acid batteries As such a push for the scientific c
84. eodorizer cosmetic use Sodium bicarbonate 0 0298 cleaning Monosodium phosphate 0 0050 Food Additive Ecowatt 6 Proposed Solution 6 1 Project Management 6 1 1 Team Organization Senior Design Course Structure and Major Deadlines Calvin College Team Advisor Industrial Consultant Team Leader Prof J Aubrey Sykes Prof Walter Rawle Jared Huffman i Calvin College Calvin College MFC Design Feed and Water Biological Output Regulation System Cube and MEC S WEB Components te Mj Case Design Chris Michaels Achyut Shrestha Brianna Bultema Jared Huffman Microbiologist Civil Engineering Microbiologist Engineering Lab i Manager Prof Gemma Prof Ray Hozalski Prof John Wertz Reguera Michigan State University University of Minnesota Twin Cities Robert DeKraker Calvin College Calvin College Graduate Research Assistant Chris Harrington University of Minnesota Twin Cities Figure 2 Team Organization Chart Ecowatt 6 1 2 Team Member Bios Brianna Bultema BSE CHEM Brianna is a fourth year senior engineering student with a chemical concentration and additional course work in biology She grew up in the shadow of the Rocky Mountains in Colorado Springs CO where she learned to appreciate and cherish nature Her biology course work and independent laboratory knowledg
85. ete 42 SchmartBoard from SchmartBoard and a 20V 700MA S MINI Schottky diode from Panasonic SSG All other resistors and capacitors are available in the Calvin College Electrical Engineering Lab The voltage produced by the MFCs is not constant enough for consideration as a reliable power source so regulation is necessary for application The voltage regulator adjusts the input voltage to a set internal reference voltage This means that the voltage regulator is programmable by means of a network of analog devices on the outside of the voltage regulator chip itself By internally switching the voltage to check the voltage the MAX1524 is capable of Ecowatt putting out a desirable voltage Calculating the correct switching frequency and maximum duty cycle reduces the amount of noise produced by the circuit and Biobattery at the output The voltage regulator is capable of leveling relatively small changes in fuel cell output Design Criteria The typical microbial fuel cell output is 0 5 volts per cell To achieve a higher voltage multiple cells are used in series to increase the voltage For reliability 3 0V is the set minimum voltage A minimum of six cells are necessary to keep the battery the regulating circuit and the measuring circuit working at optimum performance The battery s circuit design yielded four options Each design carefully considered the needs of the circuit and the needs of the battery The needs of the circuit included
86. eved by the end of this semester were oral presentations industrial consultant brief poster design website design and PPFS report Table 4 Fall 2007 Major Milestones and Dates Accomplished These were the concrete milestones that were given in course requirements We were able to accomplish all of the mentioned milestones on or before deadline Table 4 Fall 2007 Major Milestones and Dates Accomplished Presentation 1 10 16 2007 Poster Website 1 10 19 2007 Project Brief for Consultant 10 29 2007 Poster Website 2 11 21 2007 Final PPFS 12 10 2007 A similar method allowed the team to identify major milestones for the Spring 2008 semester The team managed to keep to the commitment and complete all of the major milestones on or before the provided deadlines Table 5 Spring 2008 Major Milestones and Dates Accomplished Table 5 Spring 2008 Major Milestones and Dates Accomplished Poster Website 3 2 18 2008 Project Brief 2 for Consultant 2 25 2008 Poster Website 4 3 18 2008 Presentation 3 3 24 2008 Poster Website 5 4 18 2008 Presentation 4 4 28 2008 Senior Banquet 5 3 2008 Website 6 5 5 2008 Final Report 5 7 2008 In addition to class provided milestones soft milestones were created for our specific project As the Fall 2007 semester progressed these milestones shaped the project s future direction These milestones included purchasing Geobacter creating a worki
87. ference the parts are here as well 0 39UH Power SMD inductor from API Delevan Inc a 12UF 6 3V X5R 1210 ceramic capacitor from Kemet a 62PF 100V 5 COG 0603 ceramic capacitor from Murata Electronics North America a 30V SSOT6 N channel MOSFET from Fairchild Semiconductor a Discrete 2 SchmartBoard from SchmartBoard and a 20V 700MA S MINI Schottky diode from Panasonic SSG For the exact quantity and cost please refer to the appendix 6 2 2 Case The cost of the case is largely dependent on undetermined factors The number of MFCs and their arrangement affects the size and shape of the case The type of feeding method is also dependent on the MFC arrangement and determines certain aspects of the case design Ecowatt The team anticipates the implementation of some type of plastic but the specific design is not completed Furthermore the Refill Station design is not complete Overall Ecowatt plans to maintain a Case Cost of approximately 50 with a 100 contingency 6 2 3 Biology Materials The bacteria Geobacter metallireducens ATCC 53774 will cost 175 for a single investment because the bacteria can reproduce without having to buy more Wolfe s Vitamin Solution Vitamin Supplement MD VS and Wolfe s Mineral Solution Trace Mineral Supplement MD TMS are valuable solutions for keeping the bacteria alive and healthy These cost 40 5L of media The sales order for these materials is S0807459 with the bacteria lot number being 7405983 th
88. ge to connected device when functioning properly The circuit must also ensure that it does not inadvertently damage the MFC itself e Geobacter should not outgrow its living environment nor die off when operated under standard conditions e Finally the system must be portable appealing and user friendly 3 4 Abbreviated Terms Table 1 Abbreviated Terms ADC Analog to Digital Converter IC Integrated Circuit IDE Integrated Development Environment LCD Liquid Crystal Display LED Light Emitting Diode MFC Microbial Fuel Cell MOSFET Metal Oxide Semiconducting Field Effect Transistor RoHS Reduction of Hazardous Substances USB Universal Serial Bus Ecowatt 4 Research Engineering is not designing in a void of information As such prior work was analyzed and used as a stepping stool for improvement on the current application Other approaches have been found in literature but none have had the application that Ecowatt is designing 4 1 Microbial Fuel Cell Microbial fuel cells MFC have been in research papers since the early 1970s Three main types have received the most attention in the last 15 years heterotropic photoheterotropic and sediment cells Heterotropic and photoheterotropic cells use suspended bacterial cultures to produce current Sediment cells are historically made with sediment found from the local body of water using an electrode and cathode electrically conductive meta
89. gin STK500 Loaded partfile C Program Files Atmel AVR Tools PartDescriptionFiles AVR Simulator Please wait while configuring simulator AVR Simulator ATmega169 Configured OK Coordinator The object file does not contain source code information Loaded objectfile C Documents and Settingst chyut Shrestha My Documentstsenior design ecowatt main cof a i gt E Build message jd Find in Files CgBreakpoints and Tracepoints 4 gt ATmegal69 AYR Simulator Auto Stopped e Ln 1 Col 1 CAP NUM SCRL Gmail Inbox Opera f r spring08 penoffice Figure 41 AVR Studio 4 IDE Ecowatt However writing and compiling the program must happen before the tool accepts the importation of the program For this one uses an open source program called WinAVR pronounced whenever The code for the micro controller is written in C with the help of this tool and then complied which will produce the hex file needed for downloading into the micro controller with AVR studio 4 The following figure is the IDE layout of the program Oy x B File Edit View Tools Window Help BA ABR S iia e 4 M Mae s makefile MCU name MCU atmegal69 output format can be srec ihex binary FORMAT ihex a Target file name without extension TARGET main optimization level can be 0 1 2 3 s 0 turns off optimization Note 3 is not always the best optimization level See av
90. i Add 0 625g NaHCO3 iii Add 0 0625g Ammonium Chloride iv Add 0 15g NaH2P04H20 v Add 0 025g KCI vi Add 1 7g Sodium Acetate f Degasthe media in a 1L Erlenmeyer Flask with Side Arm 5 Prepare the test tubes Repeat for each desired bacteria filled test tube 5 mins tube Fcowatt EO a Using the nitrogen tank blow the air out of a test tube b Using an automatic pipette transfer 15mL of prepared Media Solution to the test tube by guickly removing the cap and transferring the Media Solution c Continue to blow the air out of the tube with the nitrogen tank and immediately close the cap again d Add 7mL carbon dioxide e Mix the gasses by shaking the test tube f De pressurize the test tube by quickly penetrating the cap with a needle Remove the needle as soon as the tube audibly de pressurizes 6 Addthe Vitamin and Mineral Solution Repeat for each desired bacteria filled test tube 5 mins a Using a syringe and needle add 0 16mL Wolfe s Vitamin Solution b Using a syringe and needle add 0 16mL Wolfe s Mineral Solution 7 Add the bacteria Geobacter Metallireducens Repeat for each desired bacteria filled test tube 10 mins tube a Select a healthy culture light greenish brown b Sterilize the top of the culture i Using a cotton swab apply a layer of 9596 ethanol to the top of the cap on the culture solution test tube ii Using a Bunsen burner ignite the entire top of the cap burning
91. ing processes a combination of the two methods is implemented in the design The batch fed continuous feeding process will be discussed in detail in the Design section Ecowatt 5 Team Philosophy 5 1 Christian Perspective on the Project The ministry of Jesus Christ is critical to the Ecowatt team as an inspiration for change Ecowatt is making its way into an industry that for the most part seems concerned only with the design factors of low cost and high performance Seeking to make a change the design team is dedicated to three values based primarily on the example of love shown in the life Jesus Christ Any project from Ecowatt must adhere to the Fundamental Ecowatt Values of Stewardship Trust and Justice For viability s sake each project must use global resources responsibly the Biobattery project will provide an option for portable power that does not use corrosive chemicals In addition dependability and reliability are a must The Biobattery project will provide a stable power supply in a convenient easy to use package Ecowatt will publicly disclose any issues of general public or environmental safety Finally the Biobattery project is an expression of Justice the rights of non users and users are a critical consideration in the design process When considering materials environmental and health impacts are separately weighted Even in production the effect on every person is the subject of careful deliberation 5 2 Me
92. ion 117 Information sheet 274674 Nafion perfluorinated membrane Aldrich Nafion 117 thickness 0 007 in CAS Number 31175 20 8 MDL number MFCD001 32790 zoom Expand Collapse All 33 Price and Availability Product Y our Price Number USD Available to Ship Quantity Actions 274674 1EA 297 00 04 23 2008 details BEAN Descriptions Application Nafion is a perfluorinated ion exchange membrane which has a wide variety of commercial uses The acidic hydrogen ion form and derivatives are solid superacid catalysts useful in a wide variety of synthetic applications Packaging 1 ea in foil bag As a proton exchange membrane Nafion has been the focus of considerable efforts to develop improved fuel cells Legal Information Nafion is a registered trademark of E I du Pont de Nemours amp o Inc Properties eq wt 1 100 mfr no Nafion 117 length x W 8 in x 10 in thickness D 007 in solubility H20 insoluble Fcowatt IEEE 10 7 Appendix VII Software Tools AVR Butterfly kit has its own development tools for programming and debugging software called AVR Studio 4 It is available free of charge from the vendor This program downloads the compiled code to the micro controller The following figure shows the IDE interface AVR Studio ocuments and Settings Achyut ShresthaMy Documents senior design ecowatt main c
93. is a letter if c gt a Convert to upper case c amp if necessarry c mt seg LCD character table c seg unsigned int pgm read word amp LCD character table uin t8 t c Adjust mask segment mapping if digit amp 0x01 according to LCD mask OxOF Digit 1 3 5 else mask OxFO Digit 0 2 4 ptr LCD Data digit gt gt 1 digit 0 0 1 1 2 2 for i 0 i lt 4 itt nibble seg 8 0x000F seg gt gt 4 if digit 8 0x01 nibble lt lt 4 ptr ptr 6 mask nibble ptr 5 ORK kk kok k k kok k kok k kok k kok k kok k kok k koe ek kk kkk ck ck ck ck ck kk kk ck kk ck KAZ KK AA AA AA KK AKA A KA ko ko kcko kk m Function name LCD AllSegments unsigned char input Returns None g Parameters show TRUE FALSE Purpose shows or hide all all LCD segments on the LCD ck ck ck ck ck kk kk kk ck ck Ck ck KK A AAA AKA KK AKA A kc ko ko ko e w w kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk void LCD AllSegments char show 111 unsigned char i if show show OxFF Set clear all bits in all LCD registers for i 0 i lt LCD REGISTER COUNT i LCD Data i show kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kk ck ck ck ck ck ck kk ck kk ck KA KK A AAA AA KK AKA A KA ko ko e w w LCD Interrupt Routine Returns None Parameters None Purpose Latch
94. itialization void OSCCAL calibration calibrate the OSCCAL byte CLKPR 1 lt lt CLKPCE set Clock Prescaler Change Enable set prescaler 8 Inter RC 8Mhz 8 1Mhz CLKPR 1 lt lt CLKPS1 1 lt lt CLKPS0 Disable Analog Comparator power save ACSR 1 lt lt ACD Ecowatt Disable Digital input on PF0 2 power save DIDR1 7 ADCOD mt PORTB 15 lt lt PORTBO Enable pullup on PORTB 15 lt lt PBO Enable pullup on mt PORTE 15 lt lt PORTEA PORTE 15 lt lt PE4 sbi DDRB 5 set OCIA as output sbi PORTB 5 set OC1A high Button Init Initialize pin change interrupt on joystick RTC init Start timer2 asynchronous used for RTC clock TimerO Init setup timers for debounce and scroll LCD Init initialize the LCD RK KK KK I I IK I IK ke ko KKKK KKK KKK KK KKK KKK KK KK KK KK ZA A AA KK KK KKK Function name OSCCAL calibration i Returns None gt Parameters None Purpose Calibrate the internal OSCCAL byte using the external 32 168 kHz crystal as reference KKKK kk dk hg KA KA A K A A KAZ A AXA K KA ZA K AA KA kck kk ck kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk void OSCCAL calibration void unsigned char calibrate FALSE int temp unsigned char tempL CLKPR 1 lt lt CLKPCE set Clock Prescaler Change Enable set prescaler 8 Inter RC 8Mhz 8
95. k KKK koe ek kk KKK Ck ck ck ck ck ck ck kk kk ck ck Ck Ck AKA AAA KA KK A ZA kc ko KKK ko K w Function name LCD puts f Returns None Parameters pFlashStr Pointer to the string in flash scrollmode Not in use Purpose Writes a string stored in flash to the LCD ck ck ck ck ck kk kk ck kk ck Ck ck KK kk kk kk KK AKA A ko ko ko ko ko ck w k kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk mt void LCD puts f char pFlashStr char scrollmode void LCD puts f const char pFlashStr char scrollmode flash char i uint8 t i while gLCD Update Required Wait for access to buffer mt for i 0 pFlashStr i amp amp an TEXTBUFFER SIZE i for i 0 pgm read byte spFlashStr i amp amp i lt TEXTBUFFER SIZE i se mt pFlashStr i gTextBuffer i Ecowatt gTextBuffer i pgm read byte spFlashStr i gTextBuffer i 0 if i gt 6 gScrollMode 1 Scroll if text is longer than display size gScroll 0 gLCD Start Scroll Timer 3 Start up delay before scrolling the text else gScrollMode 0 gScroll 0 gLCD Update Required 1 kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kk ck kk kk kk ck ck AA e KA AAA KA KK Sk ko kc k kc ko ko ko KK KK Function name LCD puts Returns None Parameters pStr Pointer to the string Scrollmode Not in use i Purpose Writes a
96. kkkkkkkkkkkkkkkkkkkkkkkkkkkk Definitions kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk define LCD INITIAL CONTRAST OxOF define LCD TIMER SEED 3 define LCD FLASH SEED 10 define LCD REGISTER COUNT 20 define TEXTBUFFER SIZE 25 define SCROLLMODE ONCE 0x01 define SCROLLMODE LOOP 0x02 define SCROLLMODE WAVE 0x03 kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk MACROS ORR kk kok kk kok k kok k kok hh ok k kok hh koe ek kk kkk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk active TRUE FALSE define LCD SET COLON active LCD Data 8 active DEVICE SPECIFIC ATmegal69 define pLCDREG unsigned char 0xEC DEVICE SPECIFIC LCD segment register define LCD CONTRAST LEVEL level LCDCCR 0x0F amp level ATmegal69 First ORR kk kk kk Kk kk Kk KKK kk k kok k KKK ke ke ek ek k kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Global variables kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk extern volatile char gLCD Update Required extern char LCD Data LCD REGISTER COUNT extern char gTextBuffer TEXTBUFFER SIZE extern volatile char gScrollMode extern char gFlashTimer extern char gColon Ecowatt extern volatile signed char gScroll ORK kk kk kk Kk kk Kk KKK kk k kok k KKK koe ek ek e ke kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
97. l be mounted on a 4 X 4 X Plexiglas plate or Figure 7 Anode Cube Model Ecowatt a 5 X 5 X 4 Plexiglas plate and assembled into a cube structure known as the Anode Cube The large plates must be mounted vertically to allow for optimum oxygen diffusion into the Cathode Tank The electrodes that will have microbes on them will be facing inside the cube which will contain the Anodic Solution Many Anode Cubes will be suspended in a single large tank of water to act as a Cathode 6 4 2 Feeding When the Anode Cubes are first inoculated with Geobacter they must remain sealed for a period of time to allow a healthy biofilm to form If this process is not carried out properly the Geobacter could be carried out of the cubes the flow of food Once a healthy biofilm is established on the electrodes in the Anode Cubes a feeding system must be incorporated to maintain healthy Geobacter Design Considerations Criteria A properly designed feeding system will meet the requirements of the bacteria as well as the user For the bacteria to remain healthy the feed system must deliver a sufficient consistent drip of feed solution to each cube The feed solution must diffuse into the cubes and it must not contain oxygen or any other harmful contaminants Finally the waste must be removed periodically and it would be counter productive for the feed system to consume any power For the user the feed system must be easy to maintain
98. le into the chip To ensure that no large changes affect the performance of the circuit one must put the MAX1524 in bootstrap configuration a feedback loop to prevent problems in regulation to prompt proper regulation However Ecowatt s circuit currently is not in bootstrap mode due to issues discussed later Instead the input goes directly to the Vcc pin and the SHDN pin to bring the chip into operation quicker Also SET goes to ground for a lower on time at that pin which achieves a lower range for the duty cycle to handle any given load This is more suited to smaller increases in the voltage in terms of how much it needs an increase In addition by adding the diode on the output side of the circuit current will not backtrack into the input of the circuit which will stop any harmful activity to the bio battery cells For the actual testing of the electrical portion several characteristics were of interest to ensure the quality of the voltage regulator These were the input versus output for both the voltage and the current the output for any given input with a varied load the power dissipation the current and voltage at any given pin and the current load efficiency By testing specifically for these values one can ascertain the functionality of the voltage regulator In particular the input versus output will show the voltage regulator s functionality and output Next by varying the load i e adding a resistors of different values on
99. lies Free Radio Berkeley Sep 1999 6 Dec 2007 lt http www freeradio org documents Switching_Power_Supply pdf gt Chip Monolithic Ceramic Capacitors Catalog Datasheet Digi Key 14 Dec 2005 Murata Electronics North America 23 Apr 2008 lt http search digikey com scripts DkSearch dksus dll Detail name 490 1346 1 ND gt Fabaey K Boon N Siciliano S D Verhaege M Verstraete W Biofuel cells select for microbial consortia that self mediate electron transfer Appl Environ Micronil 2004 70 5373 5382 FDC633N Datasheet Digi Key Mar 1998 Fairchild Semiconductor 23 Apr 2008 lt http search digikey com scripts DkSearch dksus dll Detail name FDC633NCT ND gt Goldwasser Samuel M Notes on the Troubleshooting and Repair of Sci electronics repair FAQ 11 Feb 2007 6 Dec 2007 lt http www repairfag org sam smpsfag htm gt Groff Abbie Building a Two Chamber Microbial Fuel Cell Microbial Fuel Cells From Waste to Power in One Step The Logan Group 4 Dec 2007 lt http www microbialfuelcell org gt Logan Bruce E Bert Hamelers Rene Rozendal and Uwe Schroder Microbial fuel cell Methodology and technology n d Lovely D R Microbial Energizers Fuel cells that keep on going Microbe Volume 1 Number 7 2006 Lovely D R J F Stolz G L Nord and E J P Philips Anaerobic production of magnetite by a dissimilatory iron reducing microorganism Nature London 330 252 254 1987
100. ll Make software make clean Clean out built project files make coff Convert ELF to AVR COFF for use with AVR Studio 3 x or VMLAB make extcoff Convert ELF to AVR Extended COFF for use with AVR Studio 4 07 or greater make program Download the hex file to the device using avrdude Please customize the avrdude settings below first mak filenam filename c into th s Just compile assembler code only To rebuild project do make clean then make all MCU name MCU atmegal69 Output format binary FORMAT ihex can be srec ihex Target file name without extension TARGET main Optimization level can be 0 1 2 3 s 0 turns off optimization Note 3 is not always the best optimization level See avr libc FAQ OPT s OPT s OPT 0 List je sourc files here C dependencies are automatically generated SRC TARGET c Ecowatt If there is more than one source file append them above or modify and uncomment the following the file test c can be omitted remove inc test h and test in main c You can also wrap lines by appending a backslash to the end of the line SRC baz c XYZZY C List Assembler source files here Make them always end in a capital S Files ending in a lowercase s will not be considered source files but generated files assembler output from the compiler and will be deleted u
101. ls placed in the sediment and water above the sediment Heterotropic cells have consistently provided higher power to surface area ratios which allow for smaller electrode areas 4 2 MFC System Monitor The focus of the research was to find what exactly needs monitoring and what solutions are available to monitor the system The MFC is a dynamic system The power generation from Geobacter depends upon several biological and chemical factors Nevertheless the Monitor design for this bio battery system is in the interest of the functionality of the system and not the inner workings of Geobacter Designing a monitoring system with focus on MFC environment will lead towards experimental science which is not the objective of the Monitor The MFC produces voltage which varies overtime Monitoring the voltage produced by the MFC gives an idea about power generation The voltage output of the MFC also depends upon the feedstock available to the Geobacter and the removal of the waste from the MFC Therefore it is necessary to check if the feed is low or the waste level is high When connecting a load to MFC the current drawn by that load influences the power generated If a load draws too much current the Geobacter cannot keep up and the efficiency of the system goes down dramatically The research shows that it is necessary to monitor the current withdrawn from the system Temperature also heavily influences how active the Geobacter is in the given envir
102. mately 15 times the cost of carbon cloth our chosen electrode For the regulation portion of the Biobattery given that many revisions occurred throughout the designing process what came across as a simple task at first became quite an intricate and timely process Understanding and achieving the goals of Team Ecowatt in a timely manner became important Therefore conciseness and streamlining for the regulation part was essential to its success In essence this meant that the regulator needed thorough and quick design and testing to meet the deadline and fulfill the needs of the design criteria This being true given more time better testing will become a possibility Furthermore the replacement and repair of parts and performance on the circuit will go into effect Doing so will Fcowatt KT fix the behavior of the circuit Hence this repair of trying to make the output out of the circuit behave correctly is necessary to any further considerations for improving the circuit design 8 Acknowledgements We would like to acknowledge the following people for their support throughout the duration of this project Without their assistance and support we would not be able to undertake such a multi disciplinary process e Professor Ray Hozalski Civil Engineering University of Minnesota Twin Cities for samples supplies of electrodes membranes and information on MEAs e Chris Harrington Graduate Student Researcher University of Minnes
103. mines whether the temperature is within the range ehar Temp check void int temperature 0 char temp error F ADC init 0 temperature ADC read E if temperature gt 574 temperature lt 396 temp error T else temp error F return temp error Figure 32 Temperature Check Function Fcowatt EE Current The over current signal directly connects to one of the input ports of micro controller Whenever this signal generates it will trigger an interrupt and the micro controller will send a signal to disable the output Upon removal of the condition that caused the interrupt a re enable of the output will occur Main Program These three different signals have a specific priority The following flowchart Figure 33 Monitor Flow Chart shows the control logic of the program Activating the monitor will cause it to first check for any circuit failure Then the monitor will sense the temperature so that the Biobattery can operate at optimum conditions After that a voltage check happens to make sure the circuit produces enough power for the load The Monitor will go to power save mode when the system is idle for a minute Pushing the button once can activate the monitor Fcowatt EE Start Read input signals Over current short circuit condition Within temperature range Good OK Poor System idle gt 30 sec Yes Power save mode Figure 33 Monitor Flow
104. most 90 This Ecowatt clearly indicates that it is better to use power save mode as much as possible Therefore activating the Monitor only when the user needs to know what is happening with the system rather than constantly monitoring the system is best 6 5 2 Regulation Functionality To explain the operation of the regulator is important An input into the voltage regulator circuit enters the circuit Throughout the circuit are capacitors each of which holds a charge before discharging over time The only exceptions to this for functionality are the feed forward and feedback capacitors which ensure proper switching and ripple at the feedback pin If too much ripple occurs the result will show at the output as well Likewise the inductor discharges over time as well making the MOSFET act like a switch to prevent too much or too little charge from going to the output The MAX1524 chip senses this so that the chip will boost the voltage when the voltage and current are enough to turn the chip on from its soft start mode If the chip senses too much voltage a fault will occur turning the chip and circuit off The chip has an internal reference for voltage maintained by the voltage switching at a frequency defined by the designer which is achievable by setting the resistance in R1 and R2 according to the calculations provided by the datasheet from Maxim Setting this voltage divider the desired input and output voltages become programmab
105. nesina anake ne Aaa aaa ra s added yna innser d n ena ee 18 6 1 1 Team Organization zsz ania nadia OE dd i da dne anlage 18 612 Team Member BIOS zs s i n OGAE Gi o 19 6 1 3 Team Member Roles Description ssrrvnrarnnnvvnnernnvrvneanernvnsenennvnnnesnnrrvnssnnnnnnssnennns 20 M SE lend 21 6 1 5 Contingency Plan for Individual Failure Absence rsrrnnnrnnnvrnnvrrnnvrnnvrrnnvrnnnrrsnnsnn 27 Fcowatt KOMA 6 2 Cost Estimates for Building Prototype lt 44 44444444 lt lt 444 lt lt lt lt lt lt o0 lt e lt srrreeeerrr1s 28 6 2 1 Electrical E TE m 28 6 2 2 Case Le 28 6 2 3 Biology Material Vaa 29 6 3 Business Plan for Full Scale Production of Product 29 6 3 1 Marketing Gaci GEE ka dan dana Gd E AEEA EEA NEREA 29 6 3 2 Basic Production PROCESS zs sousedka eo dioda oO VEKS 29 DE are 30 64 DSI p Ee E E A E A E A E A E E T E 30 Bl Anode CUNS ai OGG OO R A 30 6 4 2 Fed vrede 32 6 4 3 Case Design ez Z O EX REC ERA AAA ARO KORDA AKE KRK 33 6 4 4 Microbial Fuel Cells 44 6 4 5 Fuel Cell Arrangement nasa inkasa A Eat Eo 48 6 4 6 Power Managements ecese eaa aE Ka nu eee dd AAA 49 6 4 7 FEEdME eee 49 6 4 8 AN EA o NR EPO AE di P 50 6 4 9 USB Power Switch Aaaa EE AGE GE 56 6 4 10 Monitoring System r rennnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnsnnnnnnnnnennre 56 6 4 11 Fuel Cell Arrangement Alternatives an
106. ng MFC and testing Ecowatt Geobacter the workhorse of our MFC was purchased Getting the right species of bacteria was important because these are expensive and must be handled with great care After receiving the Geobacter they are being cultured and reproduced in biology lab Geobacter will last the life of this project One of the defining milestones during the course of the project was being able to successfully test experimental setup of the microbial fuel cell This was very important because it proved that the project was feasible at least technically The other major milestone was recognizing that the voltage output from the single MFC is too little to power up anything and would have no commercial value So a multiple MFCs configured in a certain arrangement to generate a standard voltage was proposed and decided Getting a standard voltage from the cell would make it commercially viable Similarly soft milestones shaped the Spring 2008 semester phase of the project Identified milestones for the Spring 2008 semester included deciding on the nominal voltage output from the MFC testing the MFC with membrane and deciding on layout of MFCs Acquiring electrodes gold wire and suitable membranes also proved time necessary milestones for the progress of the project as a whole 6 1 5 Contingency Plan for Individual Failure Absence As a product the Biobattery is only viable with all of its features New products in this field ca
107. nnot afford superfluous features Unfortunately a product with no superfluous features with any unsuccessful or non functioning parts simply cannot function as a product Unsuccessful as a product the Biobattery can still function as a proof of concept demonstration of the functioning features MFC Contingency In the event of failure of the MFC aspect of the project Ecowatt plans to demonstrate the viability of the power regulation system through controlled input voltage A similar controlled input voltage test will verify the proper operation of the monitoring system design and the feeding system will demonstrate proper feeding and waste removal on a non functional dummy MFC Monitoring System Contingency In the event of failure of the Monitoring System aspect of the project Ecowatt plans to demonstrate the viability of the Biobattery MFCs power regulation system and feeding and waste removal system The feeding times and other monitoring functions can be determined with a handheld digital multimeter setup to indicate power status Ecowatt Power Regulation Contingency In the event of failure of the Power Regulation aspect of the project Ecowatt plans to demonstrate the viability of the Biobattery as a power supply with the MFCs monitoring system and feeding and waste removal system fully functioning An unregulated output has limited but undeniable uses such as powering an LED Feeding and Waste Removal Contingency In the e
108. od and Water Solutions is controlled by Flow Valves in line with the 4 Feed Bladder Flow Rate Valve Siphon Pump tubing to control the feed rate Additionally Check Valves are incorporated to prevent backflow issues from the Water Tank to the Anode Cubes and from the Anode Cubes to the Feed Bladder Check Valve 1 As the Solution Anode Cube 1 Anode Cube 2 Monitoring System indicates on page Error Bookmark not im defined the user will empty the Water Tank and replenish the Food Supply The Food Supply Bag must be periodically replaced whenever the bag is empty The user will return the Check Valve 2 Waste Tank emptied Food Supply Bag to the Figure 8 Feeding System Process Flow Chart manufacturer and install a replacement into the Food Supply Bag Chamber Reinstalling the Food Supply Bag into the Biobattery case will immediately begin a controlled and continuous feeding process again 6 4 3 Case Design The Biobattery Case for Ecowatt will house the various solution tanks bags electronic circuitry microbial fuel cells and the user interface for monitoring the Biobattery Design Considerations Criteria The Biobattery Case must protect the solutions from contamination and leaking and it should be aesthetically appealing as well as easy to carry The complete Biobattery should be Ecowatt lightweight The case should be made out of a low cost low density an
109. ommunity in general to use and research further on bio batteries is a must 6 3 2 Basic Production Process A facility interested in manufacturing Biobatteries on full scale level needs to account for certain intricacies of the product Either the unit must be shipped with the bacteria frozen or the Biobattery must be fed every 7 days even during shipment If the unit is shipped frozen it will require assembly upon reception The assembly would be somewhat complex requiring individual assembly and pressurization of each MFC and then incorporation into the full Biobattery case Based on this difficulty the recommended method of shipment is as a fully Ecowatt functioning non frozen unit At certain stages of the assembly an MFC is sensitive to other bacteria so some sterile processes are required Pouches of the fluid Feed Solution must be included with the product and refills will need to be sold separately to keep the Biobattery functioning For more details on Biobattery assembly see the Biobattery Assembly Instructions section in Appendix I 6 3 3 Budget The current estimate for the cost of each Biobattery is 200 500 While the electrical parts will cost less than 35 per unit the rest of the unit will cost substantially more These costs include the bacteria the container the feeding solution and for the rest of the expenses involved for the actual manufacturing of the battery The cost of labor and any other costs not liste
110. onment It cannot produce electricity when the surrounding temperature is out of range The optimal temperature range is 20 35 Celsius After finding the variables that need monitoring the research focused on how to monitor on those variables One can monitor the variables with either analog devices or digital devices Analog devices are easier to implement A mechanical voltmeter can measure the voltage output from MFC a thermometer can measure the temperature and over current protection can utilize a fuse These analog devices are all individual components Hence they Ecowatt will work regardless of other components function Digital devices are more robust Digital devices provide for a better monitoring system Integrating all the different sensors together can provide meaningful information However they are somewhat complicated to implement To implement the Monitor using digital devices will at least require a temperature sensor an ADC a micro controller and an LCD for display 4 3 Regulator Circuit Design Much of the preliminary research for the voltage regulator consisted of internet searches at sites such as Wikipedia scientific databases and scientific journals Research was limited to topologies that were possible to use for regulating and conditioning the Biobattery s specific power output When numbers for the approximate output of the Biobattery became available much better design alternatives became available as well The
111. ons gets generated The cathode is the positive terminal where the electrons will ultimately be transferred from the anode The buildup of electrons in anode causes the potential difference between the two electrodes so the electrons flow from anode to cathode generating electricity The two electrodes are made from the same material Copper electrodes are unsuitable for this design since copper has detrimental effect upon Geobacter Any non corrosive metal will work for the use of electrodes Porous graphite electrodes will be used for this particular design Electrodes can be made in different shapes and sizes For the use of this design electrodes will have a bar shape The potential of the electrode increases with the surface area of the electrodes so a porous electrode is preferred since it has larger surface area With a greater number of pores there is a larger surface area available for electron collection The greater number of pores also helps prevent clogging In the anode compartment Geobacter transfer the electrons to the electrode Pili also known as nanowires are the appendages of Geobacter the electrons produced are carried to the electrode via these pili as these Geobacter cling on the surface of the electrodes The cathode which is also the graphite electrode collects the electrons which flow from the anode In the cathode compartment oxygen acts as the final electrons acceptor The chemical reactions that take place in the cathode
112. or Design as well as to compensate for unforeseen scheduling conflicts and lead times for ordering materials Towards the end of the Fall 2007 Semester Ecowatt met to again to analyze the team s adherence to the predetermined schedule The team updated and discussed an Actual Gantt Chart for the Fall 2007 Semester Figure 4 Gantt Chart of Fall Semester Actual The research portions of the project originally perceived as preceding all other testing and prototyping continued throughout the entire semester The lead time for ordering bacteria was not accounted for and thus required an adjustment to the schedule as well However the team stayed on schedule within reason keeping each of the Senior Design deadlines as well as many of the team s own additional tasks For the Spring 2008 Semester Ecowatt planned a schedule much as it did for the Fall and the goal was to plan for the rest of the year before the end of the Fall Semester However the Spring 2008 Senior Design Schedule was not yet confirmed at that time Prof Wunder was able to provide the Spring 2007 Senior Design Schedule as a starting point this was later updated to match the official course schedule From each individual team member s own Ecowatt schedule and the Spring 2007 Semester Schedule the team derived a preliminary schedule for next semester represented with a Gantt Chart Figure 5 Gantt Chart of Spring Semester Plan Towards the end of the Spring 2008
113. ost valuable lessons we learned from this project came from the aspects we found most difficult The interdisciplinary nature of this project and team members challenged communication styles and stretched individual vocabularies Group communication was essential for each section of the design in the decision making process and prototype debugging Multiple different cultural expectations were involved in the team members that did not merge flawlessly Active listening is a tool that was developed though this project Electrical and mechanical prototyping should be started in the first semester Prototyping should be initiated as soon as possible concurrently with continuing research 7 2 Future Work Suggested future MFC work includes additional testing of different thicknesses of natural cellophane membrane to optimize proton flux Only one thickness of cellophane was tested The thicker membranes could have a decrease in proton flux but increased mechanical strength Anode cube fabrication methods could be improved by reducing the unused side surface area The anode cube currently has sides of 5 in with a 2in membrane If the overall dimensions were decreased with the membrane area kept constant the power to volume ratio would be significantly increase The possibility of Platonized cathode side electrodes would eliminate the need for a cathode tank of water and significantly decrease the overall weight of the system Platonized electrodes are approxi
114. ota Twin Cities for help with implementation procedures e Professor John Wertz Biology Department for assistance in Microbiology growth and experimentation e Professor J Aubrey Sykes Engineering Department for his ongoing role as the senior design advisor and for all of this feedback about our project e Professor Randall Brouwer Engineering Department for supplying VHDL code for ADC interface e Sam Brower Media Productions Calvin Alum for various visual design and photographic assistance e Bob DeKraker Engineering Department for logistical support with procurement of circuit components e Rich Huisman Chemistry Department for assistance with salt bridge supplies e Lori Keen Biology Department for assistance in biological procurement and lab support e Professor Walter Rawle Engineering Department and Senior Design Team Mentor for meeting with our team and assisting us with the in progress reviews e Professor Gemma Reguera Michigan State University for providing technical information and expertise Ecowatt 9 References 1210 MLCC Caps Datasheet Digi Key Mar 1998 Maxim Integrated Products 23 Apr 2008 lt http search digikey com scripts DkSearch dksus dll Detail name 399 3297 1 ND gt 4922 R Series Datasheet Digi Key Apr 2004 API Delevan Inc 23 Apr 2008 lt http search digikey com scripts DkSearch dksus dll Detail name 4922R 391L ND gt Brown Marty Switchmode Power Supp
115. oups researched are mixed and pure cultures for microbial fuel cells The term mixed culture demotes that the culture of bacteria has more than one species The mixed cultures composition ratio of one species to another changes with each generation depending on what species survives the best in the current environment Mixed cultures are typically found in nature usually from streambeds and sediment The sediment battery s generation of electricity is due to mixed cultures of bacteria found in the sediment Ecowatt One of the problems with using mixed cultures in a microbial fuel cell is that a symbiotic relationship has been shown to form in certain examples where one species creates free electrons and one species captures the energy from the free electron This relationship is not conducive to electricity generation in a microbial fuel cell because the more free electrons in the media then consumed by the second species of bacteria Another problem with mixed cultures is that attaining a culture that is efficient in free electron production is challenging to achieve Many mixed cultures only have a small portion of bacteria that are free electron generators with the majority simply consuming the organic feed in the media There have been some cases in the research where mixed cultures have produced a higher power density Fabaey 2004 One of these cases using glucose as a carbon source yielded a power density of 3 6 W m Rabaey 2003
116. over current signal This IC has multiple purposes which include USB compliance provision of other features such as over current and short circuit protection to a loaded system The regulated output connects to the input of this IC before it is possible to attach a load To provide power to a USB device some specifications need fulfillment and this IC will meet those requirements It will not change the input voltage because its main objective is to protect the system from over current withdraw by a load INPUT 12 7 V TO 5 5V OUT OUTPUT MAXI MAX1607 Figure 23 MAX1607 Circuit Layout 6 4 10 Monitoring System The main objective of the monitor is to oversee the system status and relay the relevant information about the bio battery system to a user Four main variables need monitoring the voltage output from the MFC the feed waste level the temperature of the surrounding and current drawn by the load These four parameters will help to determine the stability of the Biobattery system If any of these parameters fail or go outside of the specified range the user will need to know that a malfunction occurred Design consideration criteria The most important criterion in designing the Monitor is that the power consumption by this unit has to be at minimum Monitor will be sharing the power generated by MFC with Regulator The bulk of the power generated needs to go towards the load which will connect to the bio battery
117. pening the testing only occurred from lower voltages up to 3V Testing each part and pin on the board one probed all values for the circuit and calculated those values i e power and efficiency that needed calculation as shown in the appendix The efficiency of the circuit followed a bell shaped curve This was despite the fact that the voltage increased with every check of the electrical characteristics on the circuit In probing the circuit one must note that the noise generated by the circuit on both the input and output sides was quite significant While this is undesirable accurate measurements were necessary In measuring the circuit with the oscilloscope somewhat of an oddity came to attention the amperage increased amp for voltage as the voltage increased Hence further study is necessary on this matter to confirm the validity of the measurements For this reason further refinement of the circuit is necessary which is in a later section Nonetheless some charts of the results of the testing are below lout mA Vout V Ecowatt Input Voltage vs Output Voltage O N R G O 4 o S eet Vin uU i Figure 36 Input Voltage vs Output Voltage Input Current vs Output Current 9000 8000 7000 6000 5000 4000 3000 2000 1000 doi E Figure 37 Input Current vs Output Current Ecowatt Input Power vs Output Power gt o
118. plicated and expensive to implement Pumps would be necessary to continually draw the food supply into the microbial fuel cell the power for such pumps would use more energy than the Biobattery could possibly generate rendering them unfeasible To optimize the benefits and overcome the drawbacks to both batch and continuous feeding processes a combination of the two methods is implemented in the design The batch fed continuous feeding process will be discussed in detail in the Design section 6 4 8 Regulation Because the circuit requires low power usage one specialty circuit component the MAX1524 is important This part is a Simple SOT23 Boost Controller that will adjust the voltage at a frequency of 296 kHz The MAX1524 consumes little power while maintaining stable performance and uses bootstrapping to increased performance in chip start up The MAX1524 also has the ability to detect faults to protect the rest of the circuit from low voltages where the chip will try to restart itself to maintain optimum performance While other parts received consideration for usage in the design of the regulator none of the other parts achieved the desired results The other required parts in the circuit are a 3 9UH Power SMD inductor from API Delevan Inc a 12UF 6 3V X5R 1210 ceramic capacitor from Kemet a 62PF 100V 596 COG 0603 ceramic capacitor from Murata Electronics North America a 30V SSOT6 N channel MOSFET from Fairchild Semiconductor a Discr
119. pon make clean Even though the DOS Win filesystem matches both s and S the same it will preserve the spelling of the filenames and gcc itself does care about how the name is spelled on its command line ASRC List any extra directories to look for include files here Each directory must be seperated by a space EXTRAINCDIRS Optional compiler flags g generate debugging information for GDB or for COFF conversion ep optimization level List tuning see gcc manual and avr libc documentation Wall warning level SWS sss tell GCC to pass this to the assembler ahlms create assembler listing CFLAGS g O OPT funsigned char funsigned bitfields fpack struct fshort enums N Wall Wstrict prototypes N Wa adhlns lt c lst N patsubst I EXTRAINCDIRS Set a standard flag language compiler 119 Unremark just one line below to set the language standard to use gnu99 C99 GNU extensions See GCC manual for more information HCFLAGS std c89 HCFLAGS std gnu89 HCFLAGS std c99 CFLAGS std gnu99 Optional assembler flags Wa tell GCC to pass this to the assembler ahlms create listing gstabs have the assembler creat line number information note that for use in COFF files additional information about filenames and function names needs to be present in the assembler source files se
120. project Each team member is responsible for completing their assigned sections as well as helping the other members finish their part Although the divided section is complete in itself it is of little use without the integration so the integration of the project will require the expertise from the each member in their assigned sections The role of each member has been properly defined and designated Table 3 Team Member Roles Jared Huffman is the leader of the project He is responsible for overseeing that the project is completed in timely manner As a designer his primary responsibility is to design a case for the system and integrate the different parts together His job is to make the product user friendly to the extent possible Brianna Bultema is primarily responsible for the biochemical part of the project Her job description includes but not limited to overseeing welfare of the Geobacter and help setup a proper environment for the microbial fuel cell Her work is closely related to the biology and chemistry aspect of the project Chris Michaels is responsible for designing an output regulator circuit His work is to devise a circuit that will take the voltage from the MFC and stabilize it before optimizing the voltage to a specified output level He will also be testing the working of a final prototype Achyut Shrestha is responsible for designing MFC system monitor His job is to design a circuit that will oversee the system stat
121. projects throughout his high school and college education Christopher Michaels BSE EE Christopher Michaels is a fifth year Engineering student with an Electrical and Computer Concentration This past summer he held an internship at the Holland Board of Public Works He is from Mackinaw City Michigan He wishes to design high fidelity audio equipment after graduation which reflects his musical interests Also he would like to utilize his Japanese language skills Achyut Shrestha BSE ELEC Achyut Shrestha is a senior engineering student with an electrical concentration He comes from a small town called Damauli in Nepal home of the Himalayas His first name literally means man of integrity and he gives his best to portray it He grew up in family where principles are highly valued He is currently working as a software programmer in Calvin s IT Ecowatt department His affinity to learn new things both educational and social makes him very adaptable He excels on pressure and the engineering program in his school has provided ample opportunities His passion is in cutting edge technology however he wants to use his engineering knowledge and skill to help people from his country where basic necessity is more important than high tech gadgets 6 1 3 Team Member Roles Description The project has been evenly divided for the four members of the team Contribution from each team member is essential for the successful completion of the
122. r Save sleep mod kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk iA SIGNAL SIG OVERFLOW2 static char LeapMonth gSECOND increment second gPowerSaveTimer increment time until sleep timer gWakeUpTimer increment time until wake up timer if gSECON 60 gSECOND 0 gMINUTE if gMINUTE gt 59 gMINUTE 0 QHOUR if gHOUR gt 23 gHOUR 0 gDAY Check for leap year if month February if gMONTH 2 Ecowatt if gYEAR amp 0x0003 if gYEARS4 0 if gYEAR 100 0 LE gYEAR 400 0 LeapMonth 1 else LeapMonth 0 else LeapMonth else LeapMonth 0 else LeapMonth 0 Now we can check for month length if gDAY gt MonthLength gMONTH LeapMonth gDAY 1 gMONTH if gMONTH gt 12 gMONTH 1 gYEAR kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk ck kk kk ck ck hg KA KA A K A K KA A AXA K KA ZA K AKA he ck kk Function name Timer0 Init Returns None Parameters None Purpose Initialize Timer Counter 0 ck ck ck ck ck ck ck ck ck ck ck ck ck AA AA A ck AXA AXA AX X kA k kA Sk ko ko ko ko k ok KKK KKK KKK KKK KKK KKK KKK KKK KK KKK void Timer0 Init void mt char i uint8 t i Initialize callback functions for i 0 i lt TIMERO NUM CALLBACKS i array of 114 CallbackFunc i NUL
123. r libc FAQ HOPT 5 OPT S OPT 0 List C source files here C dependencies are automatically generated SRC TARGET C If there is more than one source file append them above or modify and uncomment the following the file test c can be omitted remove inc test h and test in main c SRC bcd c led functions c 4 lcd driver c X ADC C X RTC C X timero c X button c 4 extinterrupt c vcard c Errors none gt Process Exit Code 0 gt Time Taken 00 04 1 1 424 ANSI CR LF INS Ready Gmail Inb ere fr springos monitor OpenOffice lt gt Programmer s Notepa N ja 4 04 PM Figure 42 WinAVR IDE 10 8 Appendix VIII ATMega169 Specifications 10 8 1 Features High Performance Low Power AVRo 8 Bit Microcontroller Advanced RISC Architecture 130 Powerful Instructions Most Single Clock Cycle Execution 32 x 8 General Purpose Working Registers Fully Static Operation Up to 16 MIPS Throughput at 16 MHz On Chip 2 cycle Multiplier Non volatile Program and Data Memories 16K bytes of In System Self Programmable Flash Endurance 10 000 Write Erase Cycles Optional Boot Code Section with Independent Lock Bits In System Programming by On chip Boot Program True Read While Write Operation 512 bytes EEPROM Endurance 100 000 Write Erase Cycles 1K byte Internal SRAM Programming Lock for Software Security JTAG
124. rangement Three options exist for the fuel cell arrangement series parallel or both When the fuel cells are in series the voltages of each cell will add together If one of the cell s outputs becomes unusable it will short the circuit between the rest of the cells In the final design this has the potential to become difficult to repair As a result one small malfunction can cripple the entire battery such as the death of the bacteria in one of the cells Fcowatt ME The second option is arranging the fuel cells in parallel While this option can possibly suffer from lower voltage output the current is additive If one cell fails the same voltage will result For the purpose of having a reliable current and voltage the fuel cell arrangement decision needs careful consideration Therefore Ecowatt decided to use a combination of both parallel and series for the fuel cell arrangement The fuel cell arrangement reguires a compromise between the two of these options which leads to the third option By placing a small amount of resistance between the fuel cells and running half of the fuel cells in series with the other half in parallel one can simultaneously receive the result of having a circuit in both series and parallel 6 4 6 Power Management The next major module in the bio battery design is Power Management The voltage produced by the MFC needs regulation before powering a load is feasible A USB female port will power a load
125. rode to the end of the wire using a conductive epoxy or cement 2 Prepare the cap One for each desired bacteria filled test tube up to 16 20 min 5 mins tube Requires Rich Huismanj a Obtain a rubber stopper of size 4 b Insert a custom bent glass tube i Ask Rich to bend a glass tube 18 into three sides of a square ii Ask Rich to help create a hole in the rubber stopper for the custom bent glass tube c Insert the wire into the cap i Pierce the cap with a 16 gauge needle ii Thread the wire through the needle leaving enough wire for the electrode to hang suspended just above the bottom of the test tube Ecowatt iii Remove the needle leaving the wire in the cap 3 Prepare the Salt Bridge Repeat for each desired bacteria filled test tube 20 mins 5 mins tube a Boil 30mL de ionized water in a 100mL beaker with a stir bar b Stir the solution and add ingredients i Add 1 5g KCI ii Add 2 5g Ultra Pure Agar c Using a 16 gauge needle and a 10mL syringe quickly add the Agar solution to the custom bent glass tube from part 2 with as few bubbles as possible The Agar solution will cool quickly and solidify 4 Prepare Media Solution No Autoclave 45 mins a Boil 100mL de ionized water in a 250mL Erlenmeyer Flask b Add 3 425g Sodium citrate 13 7g L c Cool to room temp using ice bath d Adjust the pH to 6 0 using 10M NaOH e Addto the solution i Add 150mL de ionized water i
126. rom assembler source files 5 0 5 8 echo echo MSG ASSEMBLING lt CC c ALL ASFLAGS lt o Q Target clean project clean begin clean list finished end clean list echo echo MSG CLEANING REMOVE TARGET hex REMOVE TARGET eep REMOVE S TARGET obj REMOVE S TARGET cof REMOVE TARGET elf REMOVE TARGET map REMOVE S TARGET obj REMOVE S TARGET a90 REMOVE S TARGET sym REMOVE TARGET lnk REMOVE TARGET lss REMOVE OBJ REMOVE LST REMOVE SRC c s REMOVE SRC c d Automatically generate C source code dependencies Code originally taken from the GNU make user manual and modified See README txt Credits Note that this will work mwith sh bash and sed that is shipped with WinAVR see the above This may not work with other shells or other seds SHELL variable defined set e CC MM ALL CFLAGS 122 sed s A VN o N1 0 Nl d rg gt 0 s 6 rm f Remove the if you want to see the dependency files generated include SRC c d Ecowatt Listing of phony targets PHONY all begin finish sizebefor sizeafter gccversion extcoff clean clean list program end coff 123 Ecowatt fr 10 10 Appendix X Regulator
127. ror ORR kk KKK KK KKK KKK KKK KK KKK KKK kk e e ok kk kk dk ck ck KA KKK KKK KAZ A ZA K KA ZA K KKK kk KKK Function name Button Init Returns None Parameters None e Purpose Initializes the five button pin Ck ck ck ck ck ckck AK AA AA KA KK A ZA A KA KA AKA A kckckck ko k ck kk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk void Button Init void Init port pins cbi DDRB 7 cbi DDRB 6 cbi DDRB 4 PORTB PINB MASK DDRE 0x00 PORTE PINE MASK Enable pin change interrupt on PORTB and PORTI PCMSKO PINE MASK PCMSK1 PINB MASK EIFR 1 lt lt PCIFO 1 lt lt PCIF1 EIMSK 1 lt lt PCIEO 1 lt lt PCIE1 Fl CountdownTimerHandle Timer0 AllocateCountdownTimer SIGNAL SIG PIN CHANGEO mtE PinChangeInterrupt SIGNAL SIG PIN CHANGE1 PinChangeInterrupt kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kkkkkkkkkkkkkK A K A A KAZ A AXA K KA ZA K AA kck kck KKK Function name PinChangeInterrupt Returns None Parameters None Purpose Check status on the joystick ck ck ck ck ck Ck ck kk kk AA KA KK A AAA KA KK AKA A KA ko ko K hh kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk void PinChangeInterrupt void char buttons char key Read the buttons Bit 7 6 5 4 3 2 1 0 PORTB B A O PORTE D G PORTB PORTE B A O D C Ecowatt
128. s of the team are electrical engineering concentration Achyut Shrestha and Chris Michaels one is a chemical concentration Brianna Bultema and one member is a hybrid concentration of mechanical and electrical Jared Huffman This interdisciplinary engineering team has been working on this design project through two semesters and two courses ENGR 339 and ENGR 340 Ecowatt chose their senior design project due to their interests in environmental and power generation engineering and their desire to be a service to others and God 3 Project Specification 3 1 Problem Statement Conventional batteries are widely used and may be bought at a reasonably low price These batteries can power electronics for a couple of weeks up to a year and they are thrown away Some batteries are even rechargeable and last longer but with decreased performance for every subsequent charge Unfortunately conventional batteries are not as low cost as they seem The materials used in conventional batteries are toxic not easily recyclable and harmful to the environment Inan attempt to minimize their impact battery processing centers have been implemented but the process is expensive and time consuming and the vast majority of batteries are simply discarded into the trash Ecowatt is a team that is called to answer the problems caused by conventional batteries by developing Microbial Fuel Cells into a power source that is portable consistent and reliable The
129. sene 124 Table of Figures Figure 1 Method of ApB OSEDI corr Ito ie dove Man pede d Ege doen a ao Aged oin a e dapes pu E ed dedu dens 15 Figure 2 Team Organization Chaft isa uie too pesa Per upon a eec nda dd Macs brun ep Luke aa di dteesadiudasdd 18 Figure 3 Gantt Chart of Fall Semester Plan eese eene eene 23 Figure 4 Gantt Chart of Fall Semester Actual rrrnrrrnrannnnvnnnrennvnnnsennvvenssnernenesnennrnnnsennrsenssnnnnenee 24 Figure 5 Gantt Chart of Spring Semester Plan ssrnrnrannnvvnnanennvnnnsennvvvnnennnnnnesnennrnessennrrenssnnnnenee 25 Figure 6 System Interaction reroronrnrnrnrnrnrnrnrnrnrnrnsnrnsnrnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnn 30 Figure 7 Anode Cube Model L uumuaumsansnimmenseegnuimmiube pre mi a sk dan a Eras uis 31 Figure 8 Feeding System Process Flow Chart rannrronnannnnvnnnnennvnvnesnnrvvnsannnnvnssnennvnnssennrsvnssnnnnenee 33 Figure 9 Full Case Closed PE B 35 Figure 10 Case with Food BIAdBEFS az dz W Z Roa tme qM addu 36 Figure 11 Case with Anodes CubD6 s i ii a zada aat eaa deze dac ddd 37 Figure 12 Case with Support Rails retia akin Idea Rer ex Dh equ E cube icz di 38 Fcowatt E Figure 13 Component Waste Chamber and Feed Bladder Chamber 39 Figure 14 Component Cathode Body esses esee 40 Figure 15 Component Support Rail eee eeess eee ao oe aaa aaa
130. should not be exposed to light CONDITIONS Temperature 30C Atmosphere Anaerobic 80 Na 20 CO BIOSAFETY LEVEL 1 Appropriate safety procedures should always be used with this material Laboratory safety is discussed in the following publication Biosafety in Microbiological and Biomedical Laboratories 4 ed HHS Publication No CDC 93 8395 U S Department of Health and Human Services Centers for Disease Control and Prevention Washington DC U S Government Printing Office 1999 The entire text is available online at www cdc gov od ohs biosfty bmb14 bmb1 Atoc htm 10 5 Appendix V Membrane Testing Data Cellephane 1 Nafion mL mL NaOH 1 NaOH 1 H20 29 H20 29 HCL 1M 100 HCI 1M 100 Time H Time H min pH mol L H L min pH mol L H L 0 13 21 6 17E 14 3 71E 10 0 13 35 4 47E 14 2 69E 10 2 13 1 7 94E 14 4 78E 10 1 13 31 4 90E 14 2 95E 10 3 12 97 1 07E 13 6 45E 10 2 13 13 7 41E 14 4 46E 10 4 12 87 1 35E 13 8 12E 10 3 13 09 8 13E 14 4 89E 10 5 13 83 1 48E 14 8 90E 09 10 12 85 1 41E 13 8 51E 10 7 13 09 8 13E 14 4 89E 10 36 12 32 4 79E 13 2 88E 11 10 12 91 1 23E 13 7 41E 10 13 12 78 1 66E 13 9 99E 10 15 12 75 1 78E 13 1 07E 11 31 12 72 1 91E 13 1 15E 11 180 12 08 8 32E 13 5 01E 11 1320 10 94 1 15E 11 6 91E 12 1689 10 71 1 95E 11 1 17E 13 1740 10 7 2 00E 11 1 20E 13 Ecowatt 10 6 Appendix VI Naf
131. sign must also include the safety of a user operating the device 5 3 2 Material Impact The materials involved in the design are carefully chosen to minimize the environmental impact while meeting the design goals Modularity allows most of the parts to be reusable and the Feed Bladders are to be accepted by the manufacturer for sterilization and refilling For more information on material selection see the Case Design Section on page 33 5 3 3 Chemical Biological Impact The feed solution that Geobacter consumes contains chemicals including sodium acetate sodium citrate Potassium Chloride and others Sodium acetate is one of the products of the well know fizzing reaction of baking soda and vinegar used in kid s volcano projects The two other products are carbon dioxide the fizzing gas and water Other uses for sodium acetate include food flavoring for salt and vinegar chips as a food preservative and in hand warmers Our sodium acetate is purchased from a chemical supplier and is 99 9 pure The feed solution is a dilute mixture as seen in table 2 Ecowatt Table 2 Chemical Concentration in Feed Name mol L Industrial Usage Sodium Acetate 0 0500 Food Additive Hand Warmers Sodium Citrate 0 0466 Food Additive Buffer Medical Ammonium Chloride 0 0047 Food Additive Shampoo Snow treatment Soddering Potassium Chloride 0 0013 Fertilizer Food Processing Substitution for Table Salt Baking baking soda d
132. t Schematic Ecowatt PFO port for temperature sensor The temperature sensor also connects directly to ADCO As with the voltage reading the temperature reading converts into a digital signal from an analog signal which then forwards to the micro controller via the PFO port Negative Temperature R211 Coefficient NTC NCP18WF 104J03RB resistor GND Figure 27 Temperature Sensor Schematic Ecowatt USI port for over current signal The over current signal which already is in digital form goes to the USI pin PE4 This signal tells micro controller that there is some error in the output of the system USI PH 2 54 4X1 NOT MOUNTED GND Figure 28 USI Port Schematic Output ports LCD Ecowatt The LCD connects directly to the micro controller to display all the information in text LCD4 LCD5 LCD6 LOD LCDS LCD9 LCD10 LCD11 LCD12 LCD13 LCD14 LCD15 LCD16 LCD17 LCDi32 3 ale Figure 29 LCD Schematic U200 BP3 LCD display BP2 3 BP4 BPi DEG 1ikAL AM 6 1F 1G 1B X2 51 2K 20 21 2M 1A 1J 1N 1D 3K 33 3L 3M X1 1B 1C 86 3A 3B 3C 3D 1 2F 2B 2P z 1K 4J 4L 4M 81 2H 2G 2N 5 4A 4B 4C 4D 23 2B 2C 2D Te 5K 5J 5L 5M 2 3F 3B 3P iq 5A 5B 5C 5D 82 3H 30 3N 15 2 6F 6E 6P 3 C0L1 87 7 13 99 6H 6G 6N S3 AF AR AP i4 SK 6J 6L 6M 4 4H 4G 4N Te A 6B 6C 6D S4 5F 5R 5P jg 10 7F 7E 7P 5 5H 5G 5N 17 510 78 7G 7N 85 C0L2 88 8 7K 7J 7L 7M 7A 7B 7 7D H4042 DL LCD1
133. t asynchronous clock source enable all COM pins and enable all segment pins LCDCRB 1 lt lt LCDCS 7 lt lt LCDPMO 3 lt lt LCDMUX0 Set LCD prescaler to give a framerate of 32 0 Hz LCDFRR 0 lt lt LCDPS0 7 lt lt LCDCDO LCDCRA 1 lt lt LCDEN 1 lt lt LCDAB Enable LCD and set low power waveform Enable LCD start of frame interrupt LCDCRA 1 LCDIE gLCD Update Reguired FALSE kkk kk kok kk kok k kok k kok kk kk k kok k kkk KKK kk k ck ck ck ck ck kk kk ck kk ck KA KK A AAA AA KK AKA A KA KA ko K w w Function name LCD WriteDigit char c char digit di Returns None Parameters Inputs c The symbol to be displayed in a LCD digit digit In which digit 0 5 the should be displayed symbol Note Digit 0 is the first used digit on the LCD i e LCD digit 2 Purpose Stores LCD control data in the LCD displayData buffer The LCD displayData is latched in the LCD SOF interrupt ck ck ck ck ck ck ck KKK ck ck ck kk ck ck ck KKK koc ke ko ck ko ko k kv ko ko ko ko k ok kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk void LCD WriteDigit char c char digit unsigned int seg 0x0000 Holds the segment pattern char mask nibble char ptr char i if digit gt 5 Skip if digit is illegal Ecowatt return Lookup character table for segmet data if c gt 66 c lt z c
134. the LCD displayData and Set LCD status updateComplete ck ck ck ck ck kk kk ck kk ck KA KK A AAA KA KK AKA A KA KA AK w w kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk SIGNAL SIG_LCD static char LCD TIMER SEED char c char c flash char flash LCD timer char EOL unsigned char i PE R static char timeout count FTH static char auto joystick count c flash 0 mt kkkkkkkkkkkk k k Button timeout for the button c START kkkkkkkkkkkkkkkk EAV if gButtonTimeout timeout_count if timeout count gt 3 gButtonTimeout TRUE timeout count 0 abd f x3kk Button timeout for the button c END kkkkkkkkkkkkkkkkkk J Ecowatt o kok k ke e ek e e e e x x Auto press joystick for the main c START xwkxwuxw www if gAutoPressJoystick AUTO auto joystick count if auto joystick count gt 16 gAutoPressJoystick TRUE auto joystick count 15 else auto joystick count 0 SE KKK KKK KK e ke RK Auto press joystick for the main c END kkkkkkkkkkkkkkx LCD_timer 7 Decreased every LCD frame if gScrollMode If we are in scroll mode and the timer has expired we will update the LCD if LCD timer 0 if gLCD Start Scroll Timer 0 gLCD Update Required TRUE else gLCD Start Scroll Timer else if not scrolling disble LCD start of frame interrupt
135. the user especially when he she will need to buy it A digital system can lose many of the disadvantages of the analog meters First to reduce the size and cost all of these different units are combinable into one unit The digital system is more precise and is more user friendly The main concern with the electrical system is the power consumption however the digital components today are very efficient and use very little power The advantages of using a digital system hugely outweigh the one disadvantage which is negligible The performance of a digital system is much better than an analog system performing the same function Even though it is more effective to use digital system to monitor voltage temperature and current it is still better to leave the monitoring of feed and waste to user The change of feed and waste will occur over the period of days so that it does not need continuous monitoring The use of sensors to measure feed and waste level will only complicate the system without providing any major benefit Ecowatt An AVR butterfly development kit will serve the purpose of monitoring module The kit has built in temperature sensor which simplifies the design Implementation A digital system will carry out the monitoring of the system status and communicate the information to user Hardware The following figure shows a basic block diagram of a Monitor unit The Monitor unit will take analog inputs from the MFC and tempera
136. thod of Approach This project uses the basic approach of researching designing and implementing for a successful completion of the project Although there are three distinct phases in the project they overlap with each other over the course of the project 5 2 1 Research The first phase of the approach is research Research is of utmost importance to our project Microbial fuel cell is a recent technology and there is a lot of research going on in this field We have been able to obtain plenty of information about MFCs 5 2 2 Design The next phase of the approach is design After researching necessary materials the next step to do is develop a design of the product that we will build The design is mostly done on paper and computer The design itself is divided into other steps The first design is just the block diagram of each component in the system so there is a basic understanding of how the system should function Then next step is to take each component of the system and blow it into each individual sub system Each sub system has a block diagram of its own to show how it functions Then each components of the sub system is designed according to the required specification Ecowatt 5 2 3 Implementation The last phase of the approach is implementation or prototyping Each component of the sub system is implemented either with computer model simulation or a prototype Without implementation there is no way to know if the design actu
137. tile char gScrollMode gScroll and gScrollMode Start up delay before scrolling a string over the LCD char gLCD Start Scroll Timer 0 The gFlashTimer is used to determine the on off timing of flashing characters char gFlashTimer 0 Turns on off the colons on the LCD char gColon 0 Look up table used when converting ASCII to LCD display data segment control mt flash unsigned int LCD character table unsigned int LCD character table PROGMEM 0x0A51 3 0x2A80 4 0x0000 Not defined 0x0A00 0x0A51 Degree sign 0x0000 Not defined 0x5559 JJ TOS 0x0118 a Oxlell If 2 Ox1b11 3 0x0b50 LE 0x1b41 5 0x1f41 6 0x0111 Lf xg Ox1f51 8 0x1b51 9 0x0000 Not defined 0x0000 Not defined 0x0000 Not defined 0x0000 Not defined 0x0000 Not defined 0x0000 Not defined 0x0000 Not defined OxOf51 AT a 0x3991 B b 0x1441 C c 0x3191 Jf D t Tda Oxle41 E e 0x0e41 ZZ BY QE VEN 0x1d41 G g 0x0 50 ZZ HV GE TE 0x2080 ff YD Ya 0x1510 359 Ecowatt 0x8648 KV k 0x1440 ZE Ut qe TLT 0x0578 M m 0x8570 N n 0x1551 J S T op Tog 0x0e51 PR pj 0x9551 Q q 0x8e51 R Gr 0x9021 TS s 0x
138. ts Also by placing the resistance between the strands of lights a scenario comes into play where the resistances and the lights will not cancel each other s effects out or be able to be reduced further Similarly by placing a small amount of resistance between the fuel cells and running the half of the fuel cells in series with the other half in parallel to that series one can simultaneously receive the result of having a circuit in both series and parallel Ecowatt 6 5 Test Results 6 5 1 Monitor Voltage A variable power supply connects to the VIN port of AVR Butterfly to test the voltage In addition an external multi meter checked the actual output from the power supply In varying the output from the power supply from OV to 5V the LCD displayed the power level as expected The maximum voltage reading at Vin is 3V and since our ADC performs 10 bit conversions the accuracy of the voltage reading is 3V 210 or roughly 3mV Temperature The temperature measured by the sensor is of the surrounding environment The temperature reading occurred in different places such as a basement at room temperature and outside on a sunny day It was necessary to make a check between the temperature reading and a normal thermometer In all three different environments at different times matched the readings of temperature by the Monitor Over current Testing the over current condition was the biggest challenge The best way to test for this
139. ture sensor to convert those inputs into digital signals using ADCs A digital over current signal will go to the microprocessor through one of its ports After the microcontroller processes the signals the LCD will display meaningful information Voltage output from MFC Temperature signal Over current signal Figure 24 Monitor Block Diagram Ecowatt EJ AVR butterfly kit The heart of the Monitor design is the AVR butterfly kit The following block diagram shows the components included in the kit Please see the appendix for the full specifications LCD gt SWITCH Dataflash BUZZER PE7 PB D 3 PB 4 6 7 PE 2 3 V in VCP i ver 2i PHA 7 PORTB PB 0 7 SZ PDIO 7 PF ATmega169 1 PORTD EE PE D 1 PF2 E PE 4 6 i UART lt r 5 PB 1 3 g USI l ISP Ji 32KHZ Figure 25 AVR Butterfly Kit The ATmega 169 the micro controller is the brain of the system It is responsible for processing all the input signals and producing the appropriate output signals The Appendix shows the pin layout of this micro controller Discussion of the ports and components used is here in detail Ecowatt Input ports PF1 port for voltage input The voltage output from the MFC will connect to the VIN port This port connects directly to ADC1 which will convert the analog reading into a digital reading This digital signal will then go to the micro controller via the PF1 port GND GND Figure 26 Voltage Por
140. uld implement a Maxim Simple SOT23 Boost Controller in conjunction with one inductor one diode one MOSFET three capacitors and three resistors The design will take about 25uA of power for the chip to run correctly but it will have an output of about 85 90 efficiency Hence it is even more efficient than the previous design In addition this design allows for more flexibility in terms of designing to the needs of the Biobattery However the MAX1524 and most of the parts needed for the correct design implementation require surface mount parts which Team Ecowatt does not have the facilities Ecowatt to build on a circuit board Therefore a SchmartBoard is necessary to solder all of the surface mount parts utilized in the fourth design The last design suited the needs of the Biobattery s regulation unit This design will give low cost power at the desired power rating Moreover the MAX1524 s built in short circuit and fault protection make it ideal for the variable voltage and load coming from the Biobattery cells and the user s application Simulation While simulating the circuit is ideal this was not possible In the midst of searching for parts Ecowatt desired to find a circuit with a simulation file for PSpice Since having a simulation file was only one of the design criteria for finding a part and more important design criteria existed Ecowatt found that no part existed that fit both the rest of the design criteria and the
141. us and communicate the information to a user in an appropriate way He is also responsible for testing the initial experimental setup He also maintains the website for his team project Ecowatt Table 3 Team Member Roles Brianna Bultema Biological Components Biological Research Bacteria Management MFC inner workings Achyut Shrestha MFC Monitoring Electrical research MFC monitoring design Testing experimental setup Chris Michaels Output Regulation Electrical research Regulator circuit design Testing prototype Jared Huffman Tank Case Design Cube Structure Feeding System Tank and Case Design 6 1 4 Schedule At the start of the Fall 2007 Semester Ecowatt met to determine a schedule for the Fall Semester The schedule was determined based on each member s individual schedule as well as a list of project due dates provided by the Professors of Senior Design The task list for Senior Design was supplemented with other important tasks the team deemed important and relevant to the schedule The team estimated how many days or weeks each task was expected to require and assembled a Gantt Chart of the results Figure 3 Gantt Chart of Fall Semester Plan Throughout the Fall 2007 Semester Ecowatt met regularly to discuss important matters about the project The schedule was frequently discussed the team changed the schedule as appropriate to meet more specific or changing deadlines for Seni
142. vent of failure of the Feeding and Waste Removal aspect of the project Ecowatt plans to demonstrate the viability of the Biobattery MFCs power regulation system and monitoring system The Biobattery prototype can be constructed within a week of the demonstration to show full functionality of the concept Unfortunately the power will begin to decrease irreparably after about a week Each prototype setup would have a limited but fully functioning life 6 2 Cost Estimates for Building Prototype In making the decisions for what to buy for the Biobattery Ecowatt met together as a team discuss and debate if the part or parts concerned were worth buying This discussion had the team member who needed the parts present to the rest of the team what they needed Then that team member had to defend why they needed that part and what that part came into play in their design The rest of the team questioned their decisions critically to make sure that everything done was in the best interests of the team in terms of the product design and the budget 6 2 1 Electrical Due to the fact that Digi Key whom Ecowatt order from has a minimum quantity for the number of parts for any given part that make a part order worth the money some parts ordered came in more than the needed quantity However this allowed for some more error in the process of building the voltage regulator The parts ordered are in the Bill of Materials in the appendix For the sake of re
143. veral shapes were considered for the Anodic Structure Spheres Cylinders and Square Prisms were all analyzed as well as Cubes based on surface area to volume ratio as well as ease of construction and food transferability For all shapes analyzed an increase in volume causes a decrease in surface area to volume ratio Furthermore the cylindrical shapes could be said to most efficiently translate their internal volume into surface area but the external volume may not be as efficiently used as the more rectangular shapes Finally the shapes with rounded parts would be much more difficult to produce for the prototype from available materials Decision After analyzing the important aspects of each shape for the Anode Structure the primary decision motivator was that of available materials and fabrication methods Rounded shapes while producing slightly better surface areas per unit of internal volume are not easily constructed in a way that provides a sealed oxygen free environment Cube shapes on the other hand are easily constructed and sealed Membranes can be attached easily and electrodes can be affixed to the membranes on the cube structure simply enough Finally 4 square plates for the sides and top and bottom and 5 square plates for the front and back provide enough space to attach 2 square membrane electrode assemblies without physical contact or difficult to manage corners Implementation Each Membrane Electrode Assembly wil

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