Bridget created the first prototype from multiple Arduinos and two force levers.  It looked like this:

It looked much nicer from the mouse's point of view:

However, we wanted to shrink it down and make it more reliable.  We managed to run everything on one Adafruit M4 feather, which is reading both force levers, outputting two 12bit force readings in real-time via the two onboard DACs, and also displaying the data on a TFT display - all running on a battery :)  Here's a shot of the output of the two channels going to an oscilloscope:

Here's the most recent prototype, showing output to the display.