My daughter wants a simple timer that can be worn like a Fitbit while she's in the gym. She wants to tap the face to set a 30, 60, or 90 minute timer, and have it vibrate and beep when the time is up. I'm thinking something like a Nano in a 3D-printed case with a piezo element for both sensing the taps and sounding the beeps. Still in the conceptual stages now, hope to start breadboarding over the Christmas break.
Enjoy this project?