[kens]

I did a teardown of a Sonicare toothbrush that used an 8-bit PIC 16F1516 microcontroller. There's a lot more going on in the toothbrush than I expected. I expected a simple motor, but there's a mechanically-complex resonant coil mechanism, driven by an H-bridge. There's some expensive manufacturing in there. Another interesting thing was the toothbrush has a "pressure sensor" to tell if you're brushing too hard, but it's really a Hall-effect sensor.

http://www.righto.com/2016/09/sonicare-toothbrush-teardown.h...