Capacitance Sensor Failing: Use Interrupts instead of Polling

[jmdelahanty]

Suddenly during the last two recordings today, the capacitance sensor is behaving quite erratically. Restarting the Arduino, reconnecting pins and the MPR121 itself, and upping the sampling rate of the DAQ to make sure nothing is being missed appears to not have solved the problem. There's maybe a loose connection somewhere, but I searched for around 30 minutes and couldn't find it. Using a capacitance sensor test script isn't showing anything clearly messed up as it's registering touches okay...

There's some trials where it's capturing touches well, but many times it appears to be failing pretty severely. I'm also noticing that during the anticipatory licking it's more reliable but after the sucrose is delivered it seems to be missing licks quite a bit. I'm wondering if there's something in the Arduino code that has it being stuck and incapable of detecting/sending lick contacts that I've somehow never noticed before. After one last restart it appears that it's doing okay, but it's very concerning it's so damn unreliable so suddenly...

I think the overall implementation of this repository, from the hardware side to the software side, should be generally considered as a failure.