A project log for Feeding Experimentation Device (FED) 2.0

FED measures food intake in mice. It is battery powered and designed to be used in rodent colony caging.

lex-kravitzLex Kravitz 03/20/2018 at 22:380 Comments

This will be a log dedicated to troubleshooting.  I'll edit this post as more issues are identified and (hopefully!) resolved. 

  1. FED code won't compile in the Arduino IDE - errors about RTCZero come up. There is an incompatibility between the code for Pail Stoffregen's Timelib library that is used by FED and an older Time library in the Arduino IDE.  The issue is documented in comments here:  Long story short, to fix this, go to wherever your "Time-master" library is installed (mine was in User\Documents\Arduino\libraries\Time-master), and rename the file "Time.h" to "Time_h.h".  Restart the Arduino IDE and this should fix the issue.
  2. Motor won't turn after building hardware - Check that battery is plugged in and charged.  The motor requires the most current of anything in FED.  When it is low, or if FED is powered by USB without a battery connected, everything else can appear to work but the motor won't receive enough current to turn.
  3. FED keeps spitting out pellets and wont' stop! There are two main reasons why FED may not detect that a pellet has been dispensed:  1) If the photo-interrupter is not correctly in place the pellet may not be detected. Make sure the pellet lands in between the "arms" of the photo-interrupter. 2) The photo-interrupter works by detecting the IR LED in one arm with an IR detector in the other.  If there is a lot of ambient IR light (for instance, if FED is in direct sunlight! the photo-interrupter may not detect the pellet.  We've experienced this issue even indoors, when FED is placed in direct sunlight from a window.
  4. FED takes a while to dispense each pellet. FED will attempt to dispense a pellet and continue trying until it is successful.  If something is impeding the pellet disk from turning, this can take many attempts.  We have found that sometimes a small bit of plastic from the printing will get in the way (see yellow circle below for example).  Watch FED try to dispense with no pellets - if it seems to be getting caught make sure there is nothing impeding the turning of the disk
  5. FED dispenses 2 pellets. In our hands, this happens <1% of the time.  We have found it very hard to reduce this further.  If it is occuring at a higher frequency than this, make sure the photo-interrupter is positioned correctly as it may not be detecting the first pellet.

Please message me more issues and I'll log solutions here!