localization entities an configuration environment wireless techn
Contents
1. Advisors A ng Zbyn k Bur Hie D rof Ing V clav Pre sil CSc Department of Information Technologie Masaryk University LOCALIZATION OF ENTITIES AND CONFIGURATION OF AN ENVIRONMENT BY WIRELESS TECHNOLOGY Contents 1 aeos trc 6 2 Geographic coordinate SYSlOM diss tuo en RepRu DOR pia 7 A TC 7 A Pa e 8 2 3 Map with parallels and MeridianS oooooonnnnccccnonnnoncccccnnnnnnnncnnnnnnnnnnnccn nn na nnnnnnnnno 9 2 4 Coordinate r prosen T ON eT 9 2 4 1 Degrees minute seconds iii ae kdo dos d ies 10 2 4 2 D6GmahIEGB6S inmediatos 10 io WI STS a he ate PP T T OO E D 12 3 1 Functional requirementS oooocccccnnnnnooccccccnncnnncccnnonnnnnnnncnnnnnnnnnn nn nnnn nn nano n nn nn nena 12 3 2 Non functional requirements cccceeeeeeseccceeeeeeeeseeeeeeeeeesaaaeeeeeeseeeaneeeeetenneaes 12 3 3 Technical equi Men rostro pi 13 A eee enter ener eee eee ere rere M 13 A c 4 14 3 3 2 1 Triangular from vertex mesh topology eee 14 3 3 2 2 Triangular from DIS oce coi oiseiae n Duedeae duca Ge hb iso buscas Cu deaur nad 15 3 3 3 Buoy nodes self power supplied and energetically efficient 15 4 Material for learning and developing noire ertet e Rime oe 17 4 1 Developing material bos copie tione sed oiu Potts Fabi m tu Rn RM e REM qu MR ME 17 LOU Protoboar2. 8 2 2 PIC Programming PIC reguires some software application MPLAB to compile and debug the code a C Compiler and Asix UP to upload the binaries to the microcontroller 8 2 2 1 MPLAB IDE Microchip provide its own IDE for working with their microcontrollers called MPLAB IDE Is up to the user use another compiler MPLAB IDE allows the user to choose another one compiling from the same application It provides a debugger even with simulated UART ese Har BH Chebem Mahal ol heasibwoyiensin c Le te pur x Ex rie Ag Sembee TREES L BH SH uer BUILD SUCCEEDED MPLAB SM HCF po wo nesu DMH benk Le3LCOID NS UA Working with MPLAB IDE Page 60 8 2 2 2 C Compiler For the learning PICs of the family 12F was used the compiler B Knudsen Data BNKD from now on CC5X Nevertheless for the PIC used in the buoy of the family 18F was used the compiler BNKD CC8E 8 2 2 3 ASIX UP ASIX UP is an application that uses the ASIX PRESTO device to program PIC microcontrollers It allows to configure some parameters from its interface fie t View Device pou Pole TODA ADO Moser Mol deep v cor CF ral PS PRACEM FONTS AT aero PIM Ps id Y STVRIN P KOLE St nmm ast bubo DDE PO rih oe UO pea e ddd 13313124212 341 331 3 VINIL VIVIANA 1313231242432372313443413 1311332312432313341 12133323731431932433 VIVIANA
3. 66 characters 66 bytes to only 3 bytes It is a very important reduction and it allows to reduce critically the power consumption In addition this also improves the speed of the system because the messages are send and resend by every node very much faster 5 3 Sleep when there is nothing to do As it is said before switch off modules connected to the batteries reduce as well the power consumption For doing this we have to see how to do it for every device Device Make it sleep Wake it up i Sending to it the command Adafruit GPS Sending to it any byte via UART PMTK161 0 28 via UART PIC18F24K22 By code OSCCON IDLEN 0 By code OSCCON IDLEN 1 Power OFF ON watchdog timeout or on the C5 pin change IQRF gt RFIC By code setRFsleep By code setRFready IQRF gt TR By code igrfSleep Page 48 6 Scenario The scenario of the races consists in buoys floating in the water in an 1000 x 1000 meters area as a maximum Scenario diagram Every buoy have a PCB with a PIC 2 IQRF modules working in 2 frequencies 1 for the mesh where every buoy is a node and another to get the closer riders Page 49 Buoy devices diagram The coordinator consists in a pc in one of the sides of the race area connected to a 2 IQRF modules one for the mesh and another one for the riders IORF Mesh IORF Riders Coordinator diagram Page 50 In all of the side of the coordinator there are many r
4. Asynchronous Receiver Transmitter Basic module that allows asynchronous communication It has its own protocol SPI interface Serial Peripheral Interface It is a bus that allows synchronous serial communication interface Is commonly used for short distance communication primarily in embedded systems IDE Integrated development environment It is a software application for developing programming debugging and compiling source code that provides comprehensive facilities to the user Page 68 11 Bibliography 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Microchip Technology Inc Website http www microchip com Microchip Technology Inc PIC12F629 675 Data Sheet Microchip Technology Inc PIC12 L F1840 Data Sheet Microchip Technology Inc PIC18 L F2X 4XK22 Data Sheet MPLABO IDE Quick start guide ASIX s r o Website http www asix net B Knudsen Data CC5X User s Manual B Knudsen Data CC8E User s Manual MikroElectronika Website http www mikroe com MikroElectronika Website http www mikroe com Adafruit Website http www adafruit com Adafruit Adafruit Ultimate GPS Guide GlobalTop Technology Inc PMTK command packet Rev A08 Microrisc s r o IORF Website http www igrf org Page 69 15 Microrisc s r o IQRF Quick Start Guide 16 Microrisc s r o IQRF OS User s Manual Version 3 04D for TR 5xD 17
5. CK USB 04A Source IQRF s website Page 31 o O l 0 mi ms Li gt gt L4 gt gt ete CK USB 04A pin diagram Source CK USB 04A User guide From the software IQRF IDE we can program the device and see what is being sending through the SPI interface Programming the Smart receiver is very easier to resend these message via wireless and the same for receiving wireless messages and forwarding them via SPI to watch what is being received Some IQRF examples are codes about working in this way CK USB 04A allows debugging as well It has 2 buttons SW1 is a programmable button and SW2 is reset The XC3 port is the microUSB and the ports of XC1 are the pins for making connections similar to PIC pins Page 32 4 4 2 Learning about IORF Every IQRF device kernel is actually a PIC microcontroller with built in operating system which makes easier and faster the process of learning how to program it IQRF has many examples in its website for beginners and a quick start guide This and what has been learned of PIC is enough to start programming IQRF simple point to point networks with only 1 transmitter and 1 receiver IQRF has an UART module and SPI interface which allows the connection with the microcontroller we chose 4 4 2 1 Using self power supplied nodes DK EVAL 04A DK EVAL 04A Source IQRF s website Page 33 XC3 XC1 JP1 DK EVAL 04A pin diagram
6. Microrisc s r o IQRF OS User s Guide Version 3 04D for TR 5xD 18 Microrisc s r o IQRF OS Reference Guide Version 3 04D for TR 5xD 19 Microrisc s r o CK USB 04 IQRF Programmer and Debugger User s Guide Firmware v1 00 20 Microrisc s r o DK EVAL 04A IQRF development kit User s Guide 21 Microrisc s r o TR 52D Data Sheet 22 Microrisc s r o SPI Implementation in IQRF TR modules 23 Wikimedia Foundation Inc Wikipedia Website http www wikipedia org Page 70
7. Source DK EVAL 04A User guide This device is very similar to the previous one CK USB 04A but it has a battery and a jumper JP1 for switching it ON OFF Its XC3 port is only for charging it cannot program smart transceivers 4 4 3 TR 52DA TR 52DA Source IQRF website Page 34 ham RF EEPROM Temperature sensor 31 53V LDO voltage regulator Mond SPI UART I C HERE AD Comparator PAM 6x1 0 Peripherals TR 52DA block diagram Source TR 52D Data Shee This is the most important part of the IQRF systems Is what is programmed and in our case it can be programmed as coordinator or node lt has a temperature sensor a battery sensor an RF antenna and 2 LEDs red and green which is very useful for developing Page 35 5 Low power consumption As we said the low power consumption is one of the most important points of the project 5 1 Techniques to reduce the power consumption The most intuitive way of reducing power consumption is switching off part or all the modules connected to batteries in order to make it decrease The 3 devices we have in every buoy PIC IQRF and GPS have standby mode Another way is trying to reducing the wireless connections because they use to spend so much power If we add the fact that every message has to be resent through the mesh nodes this makes that the nodes closer to the coordinator will work almost all
8. analyses the information If there are wrong commands for example make a get in broadcast it just shows and error and does not send anything in order to avoid send invalid commands If the command is valid then it is send to the mesh Page 63 8 3 2 Node The node receive orders and execute them If the command is something that the own IQRF module can do for example check the battery status or something related with the mesh level it is just done If the node is not its task then the command is forward to the PIC microcontroller 8 3 3 Repeaters Repeaters are just a dumb version of the nodes and their only task is just to resend forward the messages to the rest of the mesh 8 4 Code PIC The PIC microcontroller has to obey the orders received by the IQRF module and obey them and answer if it is needed In addition It has to store and update the information of the GPS every time is gotten If an information of any rider is gotten then it has to send it through the mesh according the fixed criteria Page 64 9 Results 9 1 How it works We have one coordinator and many nodes of the network We will assume that all the devices are already programmed and the coordinator is connected to the computer The first step is bonding all the nodes to create a non structured mesh To do this we will use the command bond with the address 000 in order to assign addresses seguentially autobonding The bonding string wil
9. be insufficient because Page 44 this would means that the system only would work between 25 6665 N and 25 6665 S and it is a very strong restriction it only would work more or less between the tropics But to optimize even more we will work in binary so the same methodology is repeated to represent the maximum dm according the number of bits sent This is the result table km im AVOID DEC dm bin 39940 6527 110 9463 1109463 100001110110111000000 3635488 1817744 908872 454436 227218 113609 56805 28402 14201 0 37748 736 104 8576 1048576 100000000000000000000 3435974 1717987 858993 429497 214748 107374 53687 26844 13422 19 0699 18874 368 52 4288 524288 10000000000000000000 1717987 858993 429497 214748 107374 53687 26844 13422 6711 61 7994 _ 9437 184 26 2144 262144 1000000000000000000 858993 429497 214748 107374 53687 26844 13422 6711 3355 76 3329 4718 592 13 1072 131072 100000000000000000 429497 214748 107374 53687 13422 6711 3355 1678 83 2152 2359296 6 5536 65536 10000000000000000 214748 107374 53687 26844 13422 6711 3355 1678 839 86 6136 1179 648 3 2768 32768 1000000000000000 107374 53687 26844 13422 6711 3355 1678 839 419 883075 589 824 1 6384 16384 100000000000000 53687 26844 13422 6711 3365 1678 839 419 210 89 1539 1 0000 10000 10011100010000 32768 16384 8192 409 2048 1024 512 256 128 89 4836 08192 8192 10000000000000 26844 13422 6711 3355 1678 839 41
10. e 251 Command code e 38400 New baud rate value to set e End mark for end of the message e 27 Mandatory checksum Other example very useful related with the power consumption is to make the GPS enter in standby mode the command is PMTK CMD STANDBY MODE and its code is 161 PMTK161 0 28 Where e Start mark of the message e PMTK Protocol code e 161 Command code e 0 New value sleep mode e End mark for end of the message e 28 Mandatory checksum Page 21 4 2 3 Adafruit Ultimate GPS Breakout v3 This is the chosen GPS device Ultimate GPS Breakout v3 ye adatruit tall xe 1050005504 Adafruit Ultimate GPS Breakout 66 channel w 10 Hz updates Version 3 Source Adafruit s website It provide the GPS information in all the NMEA GPS messages formats and it uses UART detailed in the point 4 3 2 1 It update frequency is from 1Hz to 10 Hz lts power consumption is very low only 20mA which makes this GPS device very suitable for this project 4 3 PIC microcontrollers PIC is a kind of microcontrollers made by Microchip Technology Inc They are used in a lot of embedded systems 4 3 1 Programming PIC For programming and testing the codes developed for PIC will be used the Asix Presto connected to the pins Page 22 ASIX P ESTO Source ASIX s website 4 3 2 Learning about PIC For learning we will focus in the family 12F that is one of the simplest family o
11. it will be used the eguatorial radius Page 40 N North Pole S South Pole Calculating the Earth radius according the latitude Where e R Equatorial radius 6 356 7523 km e r radius according latitude e q latitude To know the radius according to latitude r cos a 2 e r Re cos a In the next graphic we can see how the radius size is decreasing from the equator 0 to one of the poles 90 Page 41 Perimeter according the latitude 7000 6000 5000 4000 pst E 3000 5 a 2000 1000 Latitude Earth s perimeter according the latitude First of all we have to find out the latitude where the ratio km reaches the value 1 If e 1 km and the Earth has 360 then logically 1km 12 3602 360 km When the Earth perimeter decreases until 360 km in that point 1 1 km Then we need the radius rc of the Earth when its perimeter measures 360 km 360km 2 1 7 _ 360 km 2 m Tc Replacing in the equation we had Tc cos a R e Page 42 2 1 cos a Re 360 km cos a 2 H R e 360 km _ ptm 89 4836 arccos 5 T R arccos 7 TI 6 356 7523 25 09 The latitude 89 4836 corresponds to the poles and any race will be held there because of the cold temperatures Taking into account that with 1 0 0 9999 we can represent 1 km until 89 4836 then the next step is to find out how many chars we cou
12. not simulated what means that is possible to analyse real scenarios This interfaces is very intuitive and useful it can send and receive messages through SPI to a IQRF device connected via microUSB To program the code the chosen editor was Notepad which is very friendly for IORF IDE If an error is found during the compilation just clicking in the line in IORF you are redirected to the file and line in Notepad Page 62 File Edit Search View Encoding Language Settings Macro Run Plugins Window X ale hd L Iv o0DOEB s s 4 x OB C f a 5 C3 63 Es 11 Bona E buoy mesh C c EJ la buoy mesh N c EJ if SPIRX Is anything received via SPI if SPICRCok goto restart SPI Command type set get mesh and subcommand uns8 cmd bufferCOM 0 gt gt 6 cmd amp 0x03 uns8 address bufferCOM uns8 subcmd bufferCOM 0 subcmd amp Ox3F if cmd 0x00 Set goto sendPacket else if cmd 0x01 GET if address 0xFF Get broadcast gt Not possible MSG ERR GET BROADCAS bufferCOM 0 us bufferCOM 1 bufferCOM 2 bufferCOM 3 bufferCOM bufferCOM 5 hs ex n C source file length 15188 lines 525 Ln 129 Col 17 Sel 0 0 Dos Windows UTF 8 w o BOM INS Working with Notepad 8 3 Code IQRF The code of the IQRF is mainly related with the communication 8 3 1 Coordinator The coordinator basically treat and
13. this system would not be held for example in the poles because of the cold temperatures We will see later how the latitude and does it affect to the system 175 165 155 145 135 125 115 105 95 85 75 65 55 45 35 25 15 5 5 15 25 35 45 55 65 75 85 95 105 115 125 135 145 155 165 175 Pe adi 160 150 140 130 120 110 100 90 80 60 50 40 30 20 10 WO EIO 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 Arctic Circle Tropic of Cancer Tropic of Capricorr Antarctic Circle World map with latitudes and longitudes Source Wikipedia 2 4 Coordinate representation The coordinate representation use to be in the order latitude longitude There are many notations to express it but we will focus in the more common used that contains Page 9 the one we will work with Those notations are degree minute seconds and decimal degrees We will use the coordinates of the city Brno Czech Republic as example 2 4 1 Degrees minute seconds The coordinates in degrees minute seconds system are expressed in this way 49 12 0 N 16 37 0 E Like in the time system every degree has 60 minutes and every minute has 60 seconds To transform from the degrees minutes seconds to decimal degrees is that simple as minutes seconds decimal degrees degrees 60 Ea 2 4 2 Decimal degrees The coordinates in deg
14. will have fixed number of decimals 4 because our GPS that we are working with gives the information in the format XX XXXX To avoid decimals we will multiply by 10 000 to simplify this process will be called normalize degrees from now on and the unit will be called normalized degrees n 10 000 n i 010090 fg 1 e 909 Ae Then in chars it is only necessary 2 chars to represent 1 km Now is time to convert the information we have to binary The normalization makes this process simpler because we can work with positive integers 90 9 fp 1011010 Y We need only 7 bits to represent 1 km in the longitude In total with 7 bits 27 ne 128 n 128n2 L 0 0128 10 000 n 110 9463 km 0 0128 L22 1 42 km As we just saw with 7 bits it is possible to represent until 1 42 km for longitudes Page 39 5 2 2 Longitude As we just have seen the radio km in the longitude is constant in other words no matter which latitude are we 1 of longitude always will be 110 9463 km Nevertheless the ratio km in the longitude changes according to the latitude N North Pole A Lat 84 8287 Lat 0 0 9463 km S South Pole km ratio according the latitude For this reason we need to know from which latitude until the poles the ratio km becomes 1 1 1km For the calculations we have to assume that Earth is a perfect sphere as it is said before
15. 175 165 155 145 135 125 115 105 05 85 75 65 55 45 35 25 15 5 5 15 25 35 45 55 65 75 85 95 105 115 125 135 145 155 165 175 TO 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 WO EIO 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 Tropic of Cancer Equator Tropic of Capricorr 2 E d MEME O T D P Antarctic Circle _ 4 ERE A E E E ie eee Zone where the system works green and where not red Source Wikipedia edited Taking the same example Brno had this NMEA GPS message GPRMC 225446 A 49 2000 N 16 6167 E 000 5 054 7 191194 020 3 E 6C Assuming that the data is valid and not warming character A e Latitude 49 200019 N e Longitude 16 616710 E Multiplied by 10 000 e Latitude 49200019 N e Longitude 16661 710 E Transformed to binary e Latitude 11110000001111000002 0 e Longitude 1010001010110110012 O Page 47 And taking only 7 bits for latitude 1 for North South hemisphere and 9 bits for longitude 1 for East West hemisphere e Latitude 11000002 0 e Longitude 0110110012 0 So with this format system we need only 7 1 9 1 18 bits 1 bytes 18 bits En 8 bits 3 bytes Only 3 bytes with 6 free bits to add some extra information for example if the data is valid or the GPS is warming with 1 bit A gt 1 V50 We reduced from
16. 23X2X1X9 000101 o Get The information about the battery status Returns 1 byte e Percent about battery status 0 100 Page 57 7 4 5 Set get commands summary Command Get 0000 Get status of the LED 0001 Get status of the LED 0010 Get status of the LED 0011 Get status of the LED 0100 Get GPS information 0101 Get Battery information 0111 Set Parameters Switch OFF the LEDs Switch ON the LEDs Make blink the LEDs Set the duty of the LEDs Set GPS command Duty of the LED Command for the GPS Make buoy sleep Page 58 8 Implementation The implementation of the system consists in uses this system in PCBs Printed Circuit Boards 8 1 Hardware This is the PIC microcontroller scheme inside of the PCB with all the connections uProcesor 33V Vdd RB7 PGD jae PGD RXD C3 Z RBI A RB6 PGC AGND PU RA4 RAI RB4 RB3 RBO RB2 RAO J RBS MIS ness A MCLV Vpp RE3 Vdd lk E RC3 RI PGD RX 18F24K22 lk AGND PCB circuit scheme This PCB is ready to be programmed and become a buoy of the system With several buoy we can finally generate the wanted mesh to control the Jetsurf races Page 59 8 2 Software The software used in this project is specific for every device because the code is in a very low level 8 2 1 Working environment The used operating system has been Windows 7 because majority of the software for programming this devices are made for windows
17. 40 pin diagram Source PIC12 L F1840 Data Shee UART Universal Asynchronous Receiver Transmitter is a basic module that allows asynchronous communication For the correct working in a communication both modules has to work at the same bit rate This is controlled by the register UxBRG which controls the Baud rate generator Pin Receive UART gt x RECEIVER nn BAUD RATE U UUL bi GENERATOR To TE uL jJ UART TRANSMITTER gt Transmit Simplified diagram of UART module Source MikroElectronika s website 2 microcontrollers like this are used in order to send data from the one microcontroller to the other one Page 26 Again a simple miniproject to work with this microcontroller and UART bidirectional communication with this scheme Draft circuit diagram for the miniproject working with PIC12F1840 using UART The first microcontroller will roll as master and has to send the command messages cyclically every second to the second one that roll as slave The messages are the following 1 LRON Switch on the red LED 2 LGON Switch on the green LED 3 LROFF Switch on the red LED 4 LGOFF Switch on the green LED The slave hast to obey switching on off the led red green according to the message received and send an acknowledgment to the master e ACK R gt Acknowledgment for red LED commands e ACK_G gt Acknowledgment for green LED commands Pa
18. 9 210 105 895769 0 4096 40 1000000000000 13422 6711 33565 1678 839 419 210 105 52 89 7885 0 2048 2048 100000000000 6711 3356 1678 839 419 210 105 52 26 898942 0 1024 1024 10000000000 3355 1678 839 419 210 105 52 26 13 89 9471 dm that can be represented according the number of available bits and its maximum latitude Page 45 Max latitude according bits Latitude bits Maximum latitude according the number of available bits 5 2 3 Conclusions First of all working in bits we can reduce the numbers significantly and the only thing we have to assume is multiply by 10 000 to avoid decimals and then divide by 10 000 when the data will be treated To represent the latitude number we need only 7 bits and to represent North or South we would need another bit N 0 S1 We can assume that all the races will be held at least in the latitudes between 02 and 76 3329 N and S therefore we need as a minimum 9 bits To represent East or West we would need another bit E 0 W51 The fact of send or not the North South and East West bits could be optional but if a race is held just in the equator or in the prime meridian then the system would not work because there would be same value for 2 different points for example 0 0001 N and 0 001 S and analogously 0 0001 E and 0 0001 W and this system must be prepared for all the realistic latitudes and longitudes where a race could be held Page 46
19. Me 0 PEPERIT 65 MC p teen cea 67 11 Bibliography e EU Do EC ere ease 69 Page 5 1 Introduction The implemented system consists in controlling Jetsurf races The track is delimited by buoys that are floating in the water and consequently not in a fix position Every buoy has a PIC microcontroller connected a GPS to know its exact position 2 IQRF modules to allow the communication with the rest of the system and a battery to supply electric power the electronic components This system must have to take into account the low voltage as one the most important criteria for this purpose the sent messages will be reduce in order to use the less power consumption possible As it is said for the communication part every buoy has 2 IQRF modules one is used to get the position of the drivers if there are close to the buoy and the other one works in the mesh For the mesh every buoy is considered a node and them all work together in order to send the packages to the coordinator In this way the coordinator can set and get information about all the buoys and about the riders The coordinator can send commands in broadcast or unicast mode These commands can get information about the GPS status and data get information about the battery and switch on off the LEDs Page 6 2 Geographic coordinate system The coordinate system can place a point in every position over the Earth surface It is composed
20. REE en 54 LA NOS Carer ee ere ee eee eer nee eee ee ee ee ee eee 54 7 4 Messages Protocol ss coceitecraesuceocnapatenmncciceeuvscederetvasnenceendssatecaneundencduinadverpicasanedee 54 7 4 1 Command byte a dacs semnczancidceecetanns eua eesendosssadann oecuessanadabcnss d na c bodasstukosan 54 A PP eeeeenaeaee 55 r MECEC SPR PP 55 7 4 1 3 Mesh Manage met isinnnsbcisolio talca 55 LATA RESEV err nea its 55 7 4 2 Buoy address DTO Lem 56 TAS Data Dyte S rain 56 7 4 4 Commands list and their data ninia 56 PAM LEDS GEWEET ctc en a eee a nee eee eee eee 56 TAA2 O WIEN OFF the LEDS css 57 745 3 Winch ON the LEDS io 57 7 4 4 4 Make the LEDs DIK asesora mai dalas ecu rientra ts 57 7 4 4 5 Set the duty of the EED usa rete aiprotita adas 57 FAJAS Manage GPS ida o 57 FIAT Get DANY statUS sisi tic ta 57 7 4 5 SOU GEL commands summary seu dcas io beencdernendtenentaleneitetvexatnacencisnecetes 58 8 IMple Mentalist ata ets 59 A M 59 8 2 SollWalte s laa a 60 8 2 1 Tel sek gemi m T 60 D22 A 60 PREMISE INIRE 60 8 2 2 2 RS M X rm 61 822 M Dau T E eee cee ee eee ee E ee 61 A 62 As ee 63 8 3 mM Pese ere 63 2 el e ee en eee 64 A 64 A A 64 9 c r 65 DOV RI
21. VIANA o VIANA i PRESTO PRONA ZMK ASIX UP Li l FF FF m FF m FF FF m FF rF m FF FF mmm SRSSRASRSSRRIASS AAA aren er a aca sara sem morcm aaa ra mo mo i mcm amm AAA AA AAA aaa ra Le Page 61 8 2 3 IORF IDE IQRF provides an IDE for programming and debug their devices le Edit View Project Programming Debug USB Device Tools Window Help FRI usve 44e4 A 2 A IAE MA v RX Terminal d buoy igrf a ipa Terminal Mode T SPI Test DPA Test TR 52Dx OS 3 04D es DPA Data to send 7 Auto Upload 80 00 RF Programming E 2 Source E Auto Repeat 10 x100ms Use Numbers E buoy mesh C c buoy mesh N c 5 Output HEX Macros buoy mesh C hex 7 Send Macro Direct buoy mesh N hex T B Plug ins Macro Set 1 Macro Set 2 Macro Set 3 Macro Set 4 Macro Set 5 Macro Set 6 Macro Set 7 tacro 5 TR Configuration Important Files Discovery Range test Reset all the nodes Blinkallnodes GetGPSinfonodei Last Record Marker Separator V Horizontal Data ASCII OK 3 3F4B 4F 4B 3A 23 03 20 24 BUOY MESH COORD 42 55 4F 59 20 4D 45 80 00 80 00 80 00 80 00 Em Packet Inspector CK USB 04A 4 USB Module ready communication mode B NUM Working with IQRF IDE Debugging is
22. ands list and their data According to which command is sent there will be answer or not and the data information that every command needs will be different The return policy is different for every command but basically is the requested information 7 4 4 1 LEDs getter The getter is the same for all the commands of the LED control X5X4X3X2X1X0 0000NN o Get The information about how is the LED ON or OFF and the duty Returns 1 byte X X5X5X4X3X2X1X0 e X7 Status of the LEDs 0 OFF 1 ON XoX5X4X3X2X4Xo Intensity percent between 0 and 100 Page 56 7 4 4 2 Switch OFF the LEDs e Command XaX4X3X2X4Xo 000000 o Set Switch OFF the LEDs 7 4 4 3 Switch ON the LEDs e Command XsX4X3X2XiXo0 000001 o Set Switch ON the LED 7 4 4 4 Make the LEDs blink e Command XaX4Xa3X2X4Xo 000010 o Set Make the LED blinks 7 4 4 5 Set the duty of the LED e Command X5X4X3X2X4Xo 000011 o Set Set the duty of the LED e Parameter X XoX5X4X3X2X4Xo YYYYYYYY o Where YYYYYYY 96 of duty to be set from 0 to 100 If it is greater to 100 the duty will be set to 100 7 4 4 6 Manage GPS The getter gives information about the current position of the buoy X5X4X3X2X1Xo 000100 o Get The information of the buoy position Returns 3 bytes o Set Send command to the GPS Several bytes in format NMEA PMTK 7 4 4 7 Get battery status The getter gives information about the battery status X5X4X
23. by latitude and longitude 2 1 Latitude The latitude represents the angle between the Earth eguator plane and the wanted position regarding the Earth s centre and which hemisphere North or South The latitude 0 corresponds to the equator the latitude 90 N corresponds to the North Pole and 90 S corresponds to the South Pole The lines of constant latitude are called parallels for example the Equator is the parallel with latitude 0 N North Pole Equator S South Pole Latitude for a certain point Page 7 Where e A Certain point in the Earth e C Earth s centre e a Latitude 2 2 Longitude First of all we must know what a meridian is a line completely perpendicular to all the parallels from North Pole to South Pole The meridian through Greenwich England is the prime meridian Longitude represents the angle between prime meridian and the wanted position regarding the Earth s centre and which part East or West The longitude 0 corresponds to the meridian pole and the latitude 180 corresponds with the back part of the prime meridian N North Pole Greenwich meridian Equator S South Pole Latitude for a certain point Page 8 Where e A Certain point in the Earth e C Earth s centre e a Longitude 2 3 Map with parallels and meridians It is interesting to realize what latitude corresponds to the real world because the kinds of race that
24. d c D 17 LEE acci td a eee er 18 o e E O O E cee 18 4 23 NMEA Messages suscita tii 19 4 2 1 1 NMEA GPS messages session 19 4 2 1 2 NMEA PMTK MGS SAG Bussi pia 20 4 2 3 Adatruit Ultimate GPS Breakout v8 netu ei 22 43 PIC MIGO CON TOMES t ii tias 22 PP nenene 22 4 3 2 Learning about iui Pot 23 4 3 2 1 Introducing in PIC PIOT2EO6 75 eot riesen eee entrhi tenti 23 4 3 2 1 Using UART and GPS PICT2F 184 DO scr 25 4 3 3 The definitely microcontroller for the project PIC18F24K22 29 LM el dai 30 4 4 1 Programming IQRF CK USB 04A eecse esee cera 31 4 4 2 Learning about IQRF seis vo debo teste detucos tse banus teta 33 4 4 2 1 Using self power supplied nodes DK EVAL 04A ee 33 443 TRAD DA 34 5 LOW power consu plo cito 36 5 1 Techniques to reduce the power CONSUMP ION ccoooocccccnnncononcconcnnnnnanncnonnnnnnnnnos 36 5 2 Reducing the GPRMC message sisi 36 Sel Laude D E 37 LA e EOI A 40 5 2 3 CONCI S ONS PAS P E iii ici ica as 46 5 3 Sleep when there is nothing to 0O ccconnnncccnnnnnnnncccncnonnnnnnnnonnnnnnnnnncnnanannnannnes 48 D SCENATIO ROSSO O c s 49 Nee TT 52 Z ORF TMS ncs 52 Pty Me DEM eio S 52 213 BUGY MOBS J ozv na die a uk doo koa a ak 53 T2 A 53 23 ORF TOS suert 54 Rees ase SA
25. e 1 If we choose the biggest radius the perimeter will be bigger therefore the ratio km will be bigger as well then the ratio km will be obviously smaller 2 Analogously if we choose the smallest radius the perimeter will be smaller therefore the ratio km will be smaller as well then the ratio km will be obviously bigger The last case is the critical one because it needs a bigger number to represent 1 km For this reason the calculation will be done using the Equatorial radius 5 2 1 Latitude Page 37 The longitude is constant for all the latitudes of the Earth as we can see in the next image 110 9463km 110 9463km 110 9463km 110 9463 km 110 9463 km 110 9463 km 110 9463 km 110 9463 km 110 9463 km Bar ale de bd km ratio according the longitude It makes the calculations very simple Re Equatorial radius 6 356 7523 km Perimeter 6 356 7523 km 2 n 39 940 6527 km 39 940 6527 km 3602 110 9463 km This means that every degree of longitude represents 110 9463 km over the Earth surface With only the decimal part it is possible to represent this distance from 0 0000 to 0 9999 we cover exactly 1 or 110 9463 km Therefore we will need only some digits of the decimal part to represent 1 km Page 38 To get how many degrees we need to cover 1 km is as simple as calculate the inverse 1 o 000 110 9463 km km We know that we always
26. epeater which are very similar to the buoys but without GPS and their only task is to resend the messages They are redundant and its use is just to make the mesh more reliable IORF Riders UART SPI Repeater diagram Page 51 7 Specification Following the criteria of sending as less data as possible the commands are bit level defined but trying to has an easy way of interpreting what kind of command is 7 1 IQRF mesh With all the buoys interconnected we get the IQRF mesh The mesh is responsible of the synchronization 7 1 1 DFM protocol The chosen protocol is DFM Discovered Full Mesh It allows up to 240 devices and original random placement of the nodes The way to work is the next 1 Bond all the nodes 2 Run Discovery e t makes a routing backbone divided in zones according the minimum number of hops 3 If the topology changes run Discovery again ZO Zz Z2 Z3 DFM protocol graphic Source IQRF OS User s Guide Page 52 In our case once the buoys are set in their places they will stay more or less in the same place so the topology of the mesh will not change 7 1 2 Coordinator Its tasks are mainly Manage the mesh Send messages Unicast Broadcast Send orders and reguest data to from the buoys Receive data from the riders 7 1 3 Buoy node Its tasks are mainly 7 2 PIC Set its own address bond and unbond Set power down standby Get send i
27. f PICs in order to get the first approaching The learning process consists in doing miniprojects with very simple codes but it is necessary to keep in mind that some register must to have a certain value otherwise it will not work even using the right code and everything is rightly connected 4 3 2 1 Introducing in PIC PIC12F675 This microcontroller PIC12F675 is one of the simplest in its own family It has only 8 pins Page 23 Picture of the PIC12F675 Source Microchip s website VDD 1 8 vss GP5 T1CKI OSC1 CLKIN 2 GPO ANO CIN ICSPDAT GP4 AN3 T1G OSC2 CLKOUT 3 GP1 AN1 CIN VREF ICSPCLK GP2 AN2 TOCKI INT COUT PIC12F675 GP3 MCLR VPP gt 4 PIC12F675 pin diagram Source PIC12F629 675 Data Sheef This microcontroller is very simple and has 2 pins for power supply VDD and VSS and the rest can be configured as input or output but the pin 4 that only can be configured as input The first miniproject consists in make the LEDs blink alternatively the red and green LEDs its behaviour is cyclically 1 Red ON Green OFF 2 Red OFF Green ON Page 24 Circuit for the first miniproject working with PIC12F675 4 3 2 1 Using UART and GPS PIC12F1840 This microcontroller is very similar to the previous one but it has an UART module Picture of the PIC12F1840 Page 25 Source Microchip s website uy VDD v O RA5 E RA4 5 MCLR VPP RA3 PIC 12F 18
28. f the PIC18F24K22 Source Microchip s website Page 29 MCLR VPP RE3 1 RB7 PGD RAO 2 RB6 PGC RA1 3 RB5 RA2 4 RB4 RA3 5 N RB3 RA4 O 6 RB2 RA5 7 E RB1 Vss 8 gt RBO RA7 9 c VDD RA6 O Vss RCO a RC7 RC1 RC6 RC2 RC5 RC3 RC4 PIC 18F24K22 pin diagram Source PIC18 L F2X 4XK22 Data Shee With 2 UART modules we are able to connect to each buoy 2 modules IQRF detailed in the point 4 4 and the GPS device 4 4 IQRF IQRF is a wireless technology packet oriented for low speed and low power consumption made by Microrisc s r o It works via radio frequency in low bands It can work either point to point networks and complex mesh networks The meshes use IQMESH protocol and IQRF provides many facilities to create a meshes in a simple Way This technology is very interesting for uses like telemetry and controlling as it is our case Page 30 CK USB 04A DK EVAL 04A TR 52DA IQRF devices Source IQRF s website These devices are detailed later but we need to know at least what is for each one of this devices The IQRF modules is actually the Smart transceiver in this case TR 5DA It can be programmed using the device CK USB 04A The device DK EVAL 04A cannot program the smart transceiver but has a battery and is very useful for testing 4 4 1 Programming IQRF CK USB 04A The device CK USB 04A does not have battery and only works connected to the computer through a cable microUSB lt USB
29. ge 27 Once this miniproject is done the next consists in master sending GPRMC to Slave every second Slave has to parse and store the information in its memory and then switch the red or green LED according if the gotten information is valid in other word if the GPMRC has an A or V in its validation data byte When it is done then the next step is trying with the real GPS device the one detailed in the point 4 2 3 Then what happened is that the LED blinked 4 times every second Analysing with the oscilloscope the result was this IGAL vaa 11D GU L amp W DIGITAL STORAGE OSCILLOSCOPE 1GS s Analysing the signals of the miniproject circuit data sent by the GPS yellow and the LED behaviour blue Page 28 Thanks to the oscilloscope was easy to realize that is like the message was sent like 4 times This is because the GPS by default had configured to send the information in 4 kind of NMEA GPS messages and the code only took into account the start and end marks The solution was first filtering the message detecting the GPRMC code and then configuring the GPS to send only the information in GPRMC format 4 3 3 The definitely microcontroller for the project PIC18F24K22 And finally the PIC18F24K22 that belongs to 18F family which is more complex than 12F but is not very hard to adapt the code we have from the code for 12F family This microcontroller has 16 pins 2 UART modules and SPI interface Picture o
30. l be e Command 1000 00002 8035 12810 Address 0000 0000 0016 00019 So in the IQRF IDE we could send both are valid and the same Data to send 128 000 Send 46 Auto Repeat 10 x100ms Y Use Numbers or Data to send 500500 Sena Auto Repeat 10 x 100ms Y Use Numbers It is easier to transform from binary to hexadecimal so we will work in hexadecimal from now on When the command is sent then the LED of the coordinator will start to blink While this time we have to press the button of the node which we want to bond If everything is done correctly we will see Page 65 Line Rxx Length Data ASCII 1 Rx 15 BUOY MESH COORD 2 Tx 2 80 00 3 Rx 10 OK 1 409F Those lines means 1 Welcome message 2 Autobond 3 Bond correct Bond address 1 node id 409F If an error happens then we would see Line Rx Tx Length Data ASCII 7 Tx 2 80 00 8 Rx 3 ER In this way all the nodes and repeaters must be bonded to make all of them part of the mesh Once the mesh is done it is time to place every buoy in their place and run the discovery command in order to make the topology e Command 10 0000112 8316 13110 It is done The system is created and working To send the rest of commands would be in the same way If we press the IQRF s button during 2 seconds it will sleep If this button is pressed during 5 seconds it wil
31. l unbond Page 66 10 Glossary Baud rate unit used for symbol symbols per second or modulation rate pulses per second In our case we work with digital systems so 1 Bd 1 PW Jetsurf is a high tech motorized surf board made by MSR Engines It can reach speeds about 50 km h normalized degree n corresponds to the degrees which represents the latitude and longitude multiplied by 10 000 in order to avoid decimals In this way the information is sent in binary as a positive integer PIC microcontroller Peripheral Interface Controller It is a small computer on a single integrated chip made by Microchip Technology Inc GPS Global Positioning System Is basically a device that gives the position over the Earth s surface IQRF module ntelligent Radio Frequency A programmable radio frequency transceiver with UART and SPI interfaces PCB Printed Circuit Board Board with the circuit printed on itself It is used as base for physically supporting and wiring surface mounted and socketed components NMEA National Marine Electronics Association A organization which develops electrical and data specifications for marine electronics PMTK NMEA Packet MediaTek ETEK Standard message protocol to configure some GPS devices GPS NMEA Standard message protocol of GPS notation GPRMC Recommended minimum specific GPS Transit data One of the GPS MNEA messages protocol Page 67 UART Universal
32. ld send as minimum The applied technique consists in see how much decimetres to avoid decimals we can represent according how many chars are sent and which would be the maximum latitude that can be represented for each radius multiplied and divided by powers of 10 because every char can represents from 0 to 9 As we saw in the previous section in the calculations of the longitude the technique to avoid decimals will be similar but in this case we will work with decimetres dm Page 43 This is the result table DECIMAL r km dm that can be represented according the number Latitude on dm in X chars where X km dm 9 A 110 9463 1109463 11094626 11094626 1109463 of available chars and its maximum latitude Max latitude according chars chars en Maximum latitude according the number of available chars Latitude max 39940 6527 11095 0 36000 100 00 1000000 10000000 1000000 100000 10000 25 6656 3600 10 00 100000 1000000 100000 10000 1000 84 8287 1 00 10000 100000 100001000100 89 4836 36 0 00 1000 10000 1000 100 10 89 9484 36 001 100 1000 100 10 1 89 9948 036 0 001 10 100 10 1 0 4 899995 0 086 0 0001 1 10 1 01 001 89 9999 The minimum we need to cover is 1 km 10 000 dm The green cells means that it can be represented and red cannot In this case the best choice would be to send 3 chars because 84 8287 is more than enough Sending 2 chars would
33. nformation about the battery status Forward messages to PIC from the coordinator Forward messages from PIC to the coordinator The microcontroller is the kernel of the buoy lts tasks are mainly e LEDs O O O O e GET o ON OFF Blink Duty 0 100 Data and status of the buoy s GPS e Configure GPS e Send riders data If data from the riders is received this data is sent through the IQRF mesh synced according which driver is the data from This is only as support to the IORF network because in some points of the race a rider can be very far from the coordinator Page 53 7 3 IQRF riders IQRF devices set in the Jetsurfs provide the data about their position and maybe an extra telemetry information using IQRF in another frequency 7 3 1 Coordinator Every 200 ms get the information of each one of 5 riders what implies that every IQRF rider has 40 ms to send its information 7 3 2 Nodes The nodes of every rider and synchronized and calculates and send its information during its window time For synchronization the parsing of the GPS message is used the time 0 is considered when PIC reads the GPS code GPRMC 7 4 Messages protocol First of all some key characters are defined for interpreting the commands e N Does not matter either 0 or 1 e V Value to set e X Defined later The structure of the commands is always CMD ADR PAR Where e CMD Command 1 byte e ADR Destination add
34. pecification protocol it is possible modify it Page 12 e Extensibility The system allows to add futures implementations there are reserved commands e Reliability The mesh network have repeaters which add redundant links in order to make the system reliable e Fault tolerance The mesh network is reliable and allow the failure of some nodes e Network topology The mesh topology has to be as tree The reasons are the reliability and is detailed in the point 3 3 2 e Response time The system needs real time data e Scalability The system allows from 1 to 239 nodes more than enough to cover a regular race 3 3 Technical reguirements The environment will be hard because it will be the water This point makes that obviously the system must be waterproof 3 3 1 Waterproof The hardware consists in electronic must be covered and closed to prevent that the water provoke a short circuit Page 13 3 3 2 Wireless We cannot use cables in the water because as it is said in the previous point the system works in the water For this reason it is better to work using wireless technology There are 2 kinds of networks centralized or distributed As we want to cover 1 km even in the water without walls disturbing the connection is too much distance and we would need big antennas and big batteries to supply them Thus the best option is to implement a mesh where the nodes create a structure with redundancy which provide
35. r groups for instance the first row is of the group 2 is not connected with the first row of the group 3 4 1 2 Oscilloscope An oscilloscope is an instrument to measure varying signals In our case we will use it to detect when the outputs are enabled or disables for example switching on and off a LED and when something is transmitted Oscilloscope Tektronix TDS 2012B 4 2 GPS A GPS Global Positioning System is basically a device that gives the position over the Earth s surface The information is given in the coordinate system detailed in the point 2 latitude and longitude Page 18 The GPS device we will work with is Adafruit Ultimate GPS Breakout 66 channel w 10 Hz updates Version 3 It is able to give the information in several types of GPS NMEA messages It can be configured by PMTK NMEA commands messages 4 2 1 NMEA messages All the specification for all the NMEA GPS and NMEA PMTK messages has the same pattern CODE DATA DATAN CC Where e Start mark of the message e CODE Protocol code e DATA DATAn Data of each protocol comma separated e End mark for the message e CC Mandatory checksum 4 2 1 1 NMEA GPS messages All the NMEA GPS messages has the following pattern GPXXX DATA DATAN CC Where e Start mark of the message e GPXXX Protocol code e DATA DATAn Data of each protocol comma separated e End mark for the message e CC Mandato
36. r the whole buoy Another important point to make the system more energetically Page 15 efficient is trying to send less amount of bytes needed For this reason all the packages will work in binary instead of characters There are some other technigues to reduce some message that will be explained later Page 16 4 Material for learning and developing Before learning about a complex microcontroller it is recommendable to approach the technology learning with a simple one and going step by step from that to a complex one 4 1 Developing material Before making the Printed Circuit Board is necessary to test the different devices connected each other For doing this we will use a Protoboard In addition the connection by cables allows the fact of connecting an oscilloscope and see what if something is being transmitted and its times 4 1 1 Protoboard Protoboard is a board that gives to the user the possibility of design and change the circuit easily This is very interesting for the developing process but it is interesting for the process of learning as well The chosen is this Protoboard E CALL EIC 104 Page 17 The groups 1 4 5 and 8 have 2 columns each one and this columns are connected vertically from the first row to the last Every column is independent The groups 2 3 6 and 7 have 63 rows each one and this rows are connected horizontally Every group has 5 rows and are independent of the othe
37. rees minute seconds system are expressed in this way 49 2000 N 16 6167 E But it could be represented like positive and negative coordinates e Latitude o Positive North o Negative South e Longitude o Positive East o Negative West Therefore the example in this type of notation would be 49 2000 16 6167 Page 10 To transform from the decimal degrees to degrees minutes seconds is that simple as degrees decimal degrees minutes 60 decimal degrees degrees minutes seconds 3600 decimal degrees degrees 60 Page 11 3 Requirements Before starting to work we need to know all the requirements of the system in order to made a system that satisfies what is actually wanted For doing this we detail all the requirements ordered in functional non functional and technical 3 1 Functional requirements e Create a mesh o Bond node o Unbond node e Send messages to the buoys o Unicast Broadcast o Send orders Switch on off the LEDs and set its duty Make sleep the nodes Set GPS commands o Get information Get LEDs status Get GPS data Get battery status Get riders position 3 2 Non functional reguirements e Documentation The full specification is in this document e Efficiency resource consumption The buoys require batteries and the PCB have to take into account the power consumption e Modifiability The system has several layers keeping the s
38. ress 1 byte e PAR Parameters only for setters and if it is needed 1 or several bytes And the return policy is 1 or several bits The coordinator adds OK or ERR in the firsts characters to know if the command have been correctly executed and if it is OK then information about the sender 7 4 1 Command byte What is wanted to do is defined by only one byte Page 54 X7X6 X5X4X3X2X1X0 Where X7Xg Command group set get mesh X5X4X3X2X1X0 Specific command of the specified group 7 4 1 1 Set The set commands have the following pattern 00 XXXXXX 7 4 1 2 Get The set commands have the following pattern 01 XXXXXX Getis only allowed for unicast 7 4 1 3 Mesh management The mesh management commands have the following pattern 10 XXXXXX And the available commands are X7Xe X5X4X3X2X4Xo 10 000000 Bond e X7X6 X5X4X3X2X1Xo 10 000001 Unbond X7 Xe X5X4X3X2X1Xo 10 000010 Clear all the bondings X7X6 X5X4X3X2X1X0 10 000011 Run Discovery 7 4 1 4 Reserved There is a space for future implementations following this pattern 11 XXXXXX Page 55 7 4 2 Buoy address byte The whole second byte sent is to specify the destination address X7X6X5X4X3X2X1X0 The address can be e 0 autobonding only used for bonding e 1 239 unicast e 255 broadcast 7 4 3 Data byte s The commands that need extra information are sent after the address in one or several bytes 7 4 4 Comm
39. ry checksum The one we choose is our case is GPRMC This message is by definition Recommended minimum specific GPS Transit data We will use this because as we said one of the most important points is trying to reduce the power consumption sending as less characters as possible Page 19 Using the same example than in the point 2 the city of Brno using GPRMC message would be GPRMC 225446 A 49 2000 N 16 6167 E 000 5 054 7 191194 020 3 E 6C Where e Start mark of the message e GPRMC GPRMC protocol code e 103648 Time of fix 10 36 48 UTC e A Indicates if the device is ready A or warming V e 49 2000 N Latitude 49 2000 degrees North e 16 6167 W Longitude 16 6167 degrees East e 000 5 Speed over ground in knots e 054 7 True course e 150514 Date of fix 15 May 2014 e 020 3 E Magnetic variation 20 3 degrees East e End mark for the message e 68 Mandatory checksum 4 2 1 2 NMEA PMTK message All the NMEA PMTK messages has the following pattern PMTKXXX VALUE CC Where e Start mark of the message e PMTK Protocol code e XXX Command code e VALUE New value to set e End mark for end of the message e YY Mandatory checksum Page 20 For example to set the baud rate looking for in the NMEA specification we find that the command PMTK SET NMEA BAUDRATE corresponds with the code 251 PMTK251 38400 27 Where e Start mark of the message e PMTK Protocol code
40. the time while the race is being held Thus sending as less bytes as possible is one of the priorities to reduce power consumption According to Amdahl s law to get the maximum improvement in the whole system improving a part of it In our case we have to focus in what is occupying the most common message sent and it is the coordinates buoys and riders position so our aim is to reduce the GPRMC message 5 2 Reducing the GPRMC message We need to cover the geopositioning of some objects in a region with size 1000 x 1000 meters and try to send as less amount of characters as possible For this reason we need to know which part of the GPRMC message will be transmitted and which will not The objectives are to remove the non necessary information and calculate how less is needed to represent the wanted area In the first approach the calculations will be done in decimal to simplify the concept and then transformed and adapted to binary This system will work just over the sea This fact makes the calculations more accurate because experimental the radius will be very close to the real Page 36 Things to take into account e The GPS which we work with has 4 precision decimals e Rp Polar radius 6378 1370 km e Re Equatorial radius 6 356 7523 km 6 356 8km quatorial radius Earth s shape according its radius What we have to find out is how many degrees are necessary at least to represent 1 km for the worst cas
41. the system with reliability All the nodes have to know how to redirect every packet to make it get its destination that can be another node or the coordinator There are 2 topologies to implement the network triangular from vertex and triangular from base 3 3 2 1 Triangular from vertex mesh topology 00 0 0 0 00000 0 00 02 0 000 0000 e 000000 000000 f f j j Triangular from vertex mesh topology If the mesh has a topology like this and the critical node falls then the full mesh would be disabled Page 14 3 3 2 2 Triangular from base v v vy ee eee eee e ce c 00000 0000060 000000 Triangular from base mesh topology In the other hand if the mesh topology follows this criteria and one node falls the rest of the mesh is not affected at all The package which were sent by a route through the fallen node have other options to get their destination There are the same number of nodes but there are more path redundancy that make the system more reliable 3 3 3 Buoy nodes self power supplied and energetically efficient The fact of every node is connected to the other by wireless technology make that every must be self power supplied by its own battery This batteries can t be very big because of its weight it could make the buoy sink This forces to make the nodes energetically efficient using techniques like making sleep what is not being used a part like the GPS o
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