"Know when it's time to go!"
With a microcontroller, a couple of ambient light sensors and some nifty little Mac OS X software, I was able to make it easy for people to figure out the right time to wander over to the potti.
The controller at the heart of the original iPotti #1 from 2009 defunct, sadly. Good news is that I've started working on iPotti No. 2. That's hilarious for several reasons!