I'll use this page to log ideas appearing in my head for possible projects:
- Concealed bicycle alarm: small battery operated device which would fit inside the seatpost of a bicycle, detect motion and fire an alarm when triggered to scare off potential thieves and also to notify owner (and others surrounding the bicycle). The battery could be 18650 (I think it would fit) or a small lipo. As a minimum the device should have a very powerful buzzer (piezo?), motion detector (accelerometer or vibration sensor) and some form of control from the user. Ideally it could have Bluetooth/WiFi connectivity and be controlled from an app. However, it would also be convenient to be able to be armed/disarmed using RFID. I could use an ESP32 for this and maybe include USB charging. RFID could be difficult but maybe Bluetooth/WiFi works. It should be battery efficient by going to sleep unless armed.