Honestly, it doesn't stand for anything! A couple years ago I was playing around with the concept and a song came on that mentioned "Tommy" repeatedly. I jokingly started calling it Tommy when talking to my girlfriend about it.

So every time the lights turned on or off it was "Tommy who did it" and the name just stuck. Now I'm too invested to change it.

There's a dedicated thread on the Discord channel where people are coming up with good ideas for what TOMMY stands for. Some of the suggestions are "Totally Overengineered Motion Monitoring" and "Through-Obstacle Motion Monitoring". People are still working on what the Y should stand for.