We updated the Sipper firmware (see files area for Sipper-102420Stable.zip)!  The new features/changes are:

1. It puts the processor to “sleep” in between each mouse interaction.  This results in a ~2x increase in battery life.
2. It has an additional lower power mode where it also turns off the screen whenever it’s sleeping.  To activate this, once you start a program hit “B” and it will say “DISPLAY OFF”.  This saves about 1mA which should add a couple days in theory (the processor sleeping in point #1 is more power savings).  The display will still turn on for a couple seconds whenever the mouse interacts with it.  You can hit “B” again to leave the display on full time again too.
3. It has a more accurate way of measuring sipper interaction duration.
4. A little circle appears on the screen next to each sipper when it is in use to help with troubleshooting
5. You can hit “C” when a program is running to see the filename and elapsed time for the session.
6. On the start-up screen you can hold “B” to set the date/time/sipper number as before.
7. We added the ability to use an additional output:
   1. Pins A1 and A3 are programmed to go high whenever the sipper is broken (this was true in the old code as well).  You can use these to drive external stimuli, or log sipper interactions with ephys, etc. see: https://hackaday.io/project/160388-automated-mouse-homecage-two-bottle-choice-test-v2/log/153925-ttl-output-when-mouse-interacts-with-sippers
   2. We now added the ability to send output on a 3^rd pin, dependent on the Left/Right Interactions.  The idea was to use this to control a foot shock as a specific probability to study compulsive behavior.  Ie: if he interacts with the Left sipper on 10% of the trials he gets shocked, while on the Right sipper on 30% of the trials he gets shocked.   To use this, on the start-up screen you can now hold “C” to set “probabilities” on the Left and Right sipper.  Based on these probabilities, the sipper will output a HIGH pulse on pin 12 for 1 second. 
This updated firmware has not been extensively tested beyond our lab,  please comment here if you discover any bugs!