Automated mouse homecage two-bottle choice test v2

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! 

For a different project we needed a simple tube holder to fit in a cage without a wire rack.  The sipper design was perfect, and we printed this small part of it:

This hangs over the cage edge like this:, providing a simple way to use a sipper tube as a water bottle, or for simple manual measurement.  STL in the files area!

The 3D design was developed in TinkerCAD and an editable design is available here:

https://www.tinkercad.com/things/gPan0GUSNkd

Please don't judge us! This device went though a very iterative design process so the current design build is a bit complicated.  We'll hopefully re-design this more simply and update in the future (or if someone does this please let us know so we can post better design files!).  

This log is about troubleshooting.  I'll add to it as we identify troubleshooting issues.  Please leave a comment if you know of any others!  

1) Sipper position

While the electronics on the sipper device are pretty much bulletproof, we have noticed the position of the sipper tubes can shift a bit, so these should be checked carefully.  Specifically, it's possible for one tube to move out of the detection beam, which obviously introduces error into the experiment.  Here's an example, with the red line estimating the position of the detection beam.  The sipper on the right is positioned too far from the detection beam.

We're working on updating the 3D design to reduce this possibility, but either way it's a good idea to check this before putting them in with mice!

Quick video of sippers in action, showing water vs. chocolate

We are getting closer to a finalized design for use with rats v2.0. Hope to upload it all here by the end of the month. This version has a much smaller footprint compared to the previous version. We are just working on finalizing the mounting via suction cups and the code for the volume measurement. Stay tuned!

Dr. Jibran Khokhar at the University of Guelph has modified this sipper device to measure liquid intake in rats.  Really cool!  He also added an eTape liquid level monitor to measure actual intake as well as the number of interactions with the sipper.  He plans to put the full design online soon, but in the meantime here are some photos!

We made a slight update to the code and design to give the sippers 2 TTL output connections that can sync sipper interactions with external equipment such as a fiber photometry or ephys recording system.  There is now an optional step in the instructions for which pins to solder these BNC connectors (to A1 and A3), and an update to the code to enable these pins as outputs.

We made some tweaks to the 3D design to allow the sipper device to mount onto rack-mounted vivarium cages.  This will allow for higher-throughput experiments.  

Earlier this week we assembled a sipper device and filled one tube with water and the other with diluted (1:2) chocolate ensure. We placed it in a mouse cage overnight.

Some glamour shots of the device in a mouse cage:

The next morning, guess what??  One tube was completely empty... the other untouched

First data!