The red button finally came, and I was more than ready to solder it all up. I knew I was going to use a perma-proto board, but wasn't sure where or how to mount it. Adhesive foam is gross, and I don't really want to drill holes in the stool just to mount the board.

The native openings in the stool are pretty convenient, both from a design standpoint and a getting-your-hands-in-there-to-work standpoint. I watched a lot of Flintstones reruns as a kid, and was reminded of the end credits and the giant t-bone that Fred orders at the drive-in restaurant on the way home from the drive-in movie.

Here's a real-life carhop tray:

I wanted to apply this principle and make a tray for the board that hangs on the bottom of the opening in the back. So here it is. STL is in the files.

Another problem for the 3D printer --  lift the stool by the handle, and it folds up for storage. When you have a bunch of wires and electronics inside your stool, this is not idea.

Again, I favor removable solutions where possible, so now there are foot stool lock caps. Again, STL is in the files.

O

Oh, and here's a video of it working.