I tested it all day long at the office yesterday. Works just fine, but the switch wires could stand to be longer. If I had some two-conductor stranded wire, I'd use that.

The motor is pretty loud, but no one asked about it. It probably passes for a phone on vibrate, honestly, but I'm going to print a tight-fitting pouch for it out of Ninjaflex or something.

Here's a demo video with it set to buzz after five seconds. Normal time is 20 minutes.