I'm curious: if the app is useless for brushing your teeth, what is its advertised purpose ?
---
[0]: Okay, technically, a Pi is a bit overkill, but I'm not sure if it's simple to, say, hit a web API with an Arduino.
I could see a custom built API client, but then which endpoint does it hit? If it uses the API of the ToothCoach, Inc, then you will complain about TCI getting your tooth brushing data. So it uses bluetooth to hit your phone, in which case you might as well store all the inspirational messages on your phone instead of in toothbrush EEPROM