FED3 modification to add an output port

[Maria Shujah]

Hi! 

For my experiment, I need to send input from an external processor to the FED3 to dispense a pellet and in return send back output from the FED3 to the external processor to record the performance of the animal in real-time. So, I have added an additional BNC to the FED3 device which will function as an output port. While the original built-in BNC will function as an input port. 

I followed the instruction previously discussed in the forum to modify pin 9 into an output port (https://groups.google.com/g/fedforum/c/DLanT-6I1sg/m/vG9jnl5CCQAJ). Pin 9 is the only free pin on the board but is connected to A7 which is being used for measuring the battery level. So, you will have to comprise the battery measurement feature if you are going for this modification. Shown in the images below.  

In the program (I use the original 'Dispenser' program) you can add this line of code inside a loop:

This will set pin 9 to OUTPUT. Then you can program the FED3 device to send out multiple different pulses as desired. For example, I send one pulse, two pulses, and three pulses upon a left poke, right poke, and pellet collection, respectively. You can program the RZ6 to detect these pulses corresponding to different behaviors. 

Thank you Lex for helping me with this modification! 

[Maria Shujah]

I have attached some photos of the modification below.