Connect FED3 to Arduino Uno/Raspberry Pi

[Rui Beleza]

Hey guys,

I'm fairly new to this so I'm sorry if I'll sound naive or ignorant.

Currently I am working in building a paradigm where I wanted to pair food delivery with an external stimulus (as an odor for example).

I built a system controlled by arduino/raspberry pi to deliver the odor I wanted, and I want to connect the arduino to the FED3 in a way that I can control de FED3 with the arduino. I think I could use the BNC in order to do that.

My doubt is: knowing that the arduino gives out a signal at 5V, could the FED3 receive a 5V signal or does it need to be 3.3V?

I don't want to fry anything here :)

Thanks for your time!
Best

[Lex Kravitz]

Great question!  I'm glad you asked before frying your FED3 :) 

You can set up FED3 to dispense pellets based on an external device connected to the BNC port.  There is an example program in the FED3 library called "Dispenser" that will cause the FED3 to dispense a pellet when you send a pulse to the BNC input.  However, you should not connect a 5V voltage source to the BNC input!  The BNC plug of the FED3 is connected to pin A0 on the Adalogger M0 board inside.  This pin is not 5V tolerant, so it may damage the FED3 if you attach 5V to it. BTW if you do damage the Adalogger M0 microcontroller it's not terrible - you can replace it for $20.

But if you have something working for your odors using an Arduino Uno that is putting out 5V pulses, you can either use a level shifter to turn your 5V pulses in 3.3V.  Or what I would recommend instead is just to run your code on a board that uses 3.3V logic. For instance, this is a variant of the Arduino Uno that can be swapped between 5V and 3.3V logic with a jumper. There are lots of similar boards that operate with 3.3V logic.

Hope this helps!  -Lex

[Rui Beleza]

Hi Lex,

Thanks a lot for your answer. I think I have some raspberry pi picos lying around that I bought at the time they were launched. From what I remember they output 3.3V :)

Thanks again for the help