I'm surprised that the button-switch under butt pillow worked as well as it did in my setup, I've been using it for over a year but I've made the software-setup unnecessarily complicated and so I'm rewriting it to be a single module with some bells and whistles.

RFID bracelet would work too, But I wanted my setup completely unattended. Please send me an email if you'd like to be updated about rebuild of Butt Pomodoro.