Angenent Lab – MCU Potentiostat – User Manual Elliot Friedman &am
Contents
1. m Tun E maA u m a m m ik Auxiliary Board Connections A1 Connects to main board via 3 prong connector A2 Connects to E1 board via 4 prong connector A3 Connects to main board port labeled E1 A4 Connects to E2 board via 4 prong connector A5 Connects to main board port labeled E2 A6 Connects to E3 board via 4 prong connector A7 Connects to main board port labeled E3 The SD board connects to the main board via the 10 prong connectors on either board 3 2 External connectors There are three external connectors a 6 pin connector a 3 pin connector and depending on the unit either a 2 pin or another 3 pin connector labeled with blue tape The six pin connector connects to the working and counter electrodes The unlabeled 3 pin connector connects to the reference electrodes The labeled 2 or 3 pin connector connects to the power source2. Angenent Lab MCU Potentiostat User Manual Elliot Friedman amp Alex Lee 1 Overview This user manual will provide the user with an overview of the microcontroller MCU based potentiostat developed in the Angenent Lab and instructions for its use 1 1 Parts Upon opening the black box you will find six 6 different boards arranged as shown below SDBoard _ SDBoard mee Auxiliary Board Auxiliary Board The function of each board is Main Board Contains the power for the device and houses the microcontroller Connects to and controls all other boards The liquid crystal display LCD connects to this board SD Board Contains the secure digital SD card for data storage Contains the switch to turn the LCD screen on off E1 E2 E3 Contains circuitry for electrodes 1 2 and 3 respectively Auxiliary Board Contains circuitry to process signals between E1 E2 amp E3 and the main board 1 2 Additional Components In addition to the black box there is a liquid crystal display LCD screen that plugs into the main board for real time feedback and adjustments Finally you will need a small flathead screwdriver to adjust applied potentials 2 Functions 2 1 LCD Operation Plug the LCD wire into the main board The LCD should turn on but not display anything cohesive To activate the LCD flip the switch on the SD card board This will reinitialize the LCD in its default state In the defau
3. can be adjusted as described in the table below The default setting should be for a 1mA range Current Range Jumper Setting 200 pA J2 Center Left pins connected 400 uA J2 Center Right pins connected 1 mA J3 Center Left pins connected 2 mA J4 Center Right pins connected Note Changes in current range should be noted by the user and changed via the LCD screen see section 2 3 Jumpers 4 5 amp 6 control the polarity of the applied voltage to the working electrode To apply a positive voltage connect the center pin to the right pin of J4 J5 and J6 To apply a negative voltage connect the center pin to the left pin of J4 J5 amp J6 Note Changes in polarity should be noted by the user and changed via the LCD screen see section 2 3 Angenent Lab MCU Potentiostat User Manual Elliot Friedman amp Alex Lee 2 7 2 8 Note The SD card and LCD screen display will always show a 1 kQ resistance calculation If the resistance is not at 1 kQ the LCD screen data and the SD card data will be off by the ratio set resistance 1 kQ The resistance value is stored to the SD card so that the correct readjustments can be made by the user when analyzing data 2 6 2 Magnitude To adjust the magnitude of the applied potential use the screwdriver to turn the potentiometer labeled P in diagram To decrease the magnitude turn the dial clockwise To increase turn the dial
4. counter clockwise Use the LCD screen section 2 3 to assist in setting the correct potential Adjusting the shift The shift is an operating parameter that may need to be adjusted by the user For normal operation under a 1 mA current range the shift should be set to 550 mV making the range of readable currents 550 uA to 550 uA To adjust the shift to the correct value use the potentiometer located on the auxiliary board To decrease the magnitude turn the dial clockwise To increase turn the dial counter clockwise Confirm the correct value using the LCD screen section 2 1 Programming the Microcontroller If the need to program the chip arises attach the programming device to your PC via USB and connect the other end to the 6 pins found near the bottom of the main board The red wireshould connect to the left side of the board Make sure that the jumper connector below the 6 pins is inserted otherwise the chip will not program Open up AVRstudio Go to the project folder and open up potentiostat aps The project should open up Follow the instructions found on this website to make sure that the data is stored correctly http winavr scienceprog com avr gcc tutorial using sprintf function for float numbers in avr gcc html instructions begin near the bottom starting with You may ask what to do with AVRStudio settings where makefile is generated automatically Well things are simple too in this situation Then go to Project g
5. ke a new measurement at that electrode and display the results on the LCD screen No data will be written to the SD card The default setting is to apply a negative voltage across the electrode If the user desires to apply a positive potential press the SET key A zero represents a negative potential while a one represents a positive potential The next number is the resistance applied to multiply the current Change the value to the correct resistance Holding down the SET key will return the screen to displaying the current Removing the LCD screen To remove the LCD screen flip the switch on the SD card board down and pull the LCD screen and cable out of the main board The switch will stop data from being sent to the LCD Angenent Lab MCU Potentiostat User 2 5 Resetting the SD Card Manual Elliot Friedman amp Alex Lee Anytime after the SD card is removed it will need to be reset To do this pull the SD card board out and push the black button on it If the LCD screen is plugged in and on and the screen is currently in the clock view the second line of the LCD screen will read SD card reset 2 6 Adjusting the applied potential 2 6 1 Polarity and current range m m OOI EE eeeee 8 ETITTFTT mE m E m The electrode board is showed above with the applicable connections and jumpers J1 should always be connected to from the center pin to the right pin J2 and J3 control the current range and
6. lt state you can see the date and time settings of the CPU and an operating parameter call shift Angenent Lab MCU Potentiostat User Manual Elliot Friedman amp Alex Lee 2 2 2 3 2 4 There are four buttons on the board In order from left to right these buttons are SET button Goes into set mode so user can change data INC button Increments value STAT button Rotates between the clock screen and the electrode data UPDT button Quickly updates electrode data Adjusting the clock To adjust the clock hold the SET button down while on the clock screen This button will scroll through the date and then the time to make changes To increment the value that the cursor is currently at press and hold the INC button Holding it down will allow the value to continue to increment After the correct time is set continue to hold down the SET button until the cursor disappears This will return the potentiostat to its normal operating mode and print a message on the SD card noting that the time was changed Checking the readings You can check the current status of each channel To scroll between the time indicator and the electrode statuses press the STAT button This will scroll through each electrode channel before returning to the date channel Each status channel will display the last taken measurement of the voltage being applied across the electrode and the current being read in Pressing the UPDT button will cause the CPU to ta
7. t gt Configuration Options and make sure that the device is Atmega644 and the frequency is set to 16000000 Hz The potentiostat is currently set to record data every hour To change this setting go to source files on the left bar And open main c Right at the top there is a macro called record_trigger This tells the device when to record data To set which hours you want the potentiostat to record change the hour xx to be whatever hours you want If you want it to record every single hour remove all the hour lines Keep the msec sec and min instructions as ensures that it records only once in that time and not constantly Hit F7 to program the device If there are errors make sure you go and fix them Go to Tools gt gt Program AVR gt gt Connect Select the platform AVRISP mkII and Port USB Hit connect A new window should appear Go to the Program tab and in the Flash menu hit the to browse the file location Go into the project folder default potentiostat hex Then hit the program button This should program the device 3 Connections Angenent Lab MCU Potentiostat User Manual 3 1 Connections between boards Elliot Friedman amp Alex Lee The unit should have all connections in the correct position at the beginning of use but if the need arises to unplug or re connect the boards the correct configuration is outlined below anes ae E na S LLL m a Eam ote ete
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