Lost-and-Found Radio Buzzer

As a birthday present for a friend, I prototyped a simple 434 MHz radio-communication circuit to wirelessly activate a buzzer.

There are two parts: the buzzer (receiver) and the controller (transmitter). The buzzer can be affixed to an easily-lost possession, and if you need to find where it is, pressing the button on the controller will activate the buzzer wirelessly.

Each portion of the device has a teensy, and I used a 434 MHz transmitter/receiver and the VirtualWire library for Arduino (code here). A potentiometer on the controller side allows for volume adjustment. I 3D printed a nice little box for each of the two circuits.

I also made an Instructables about the project with detailed explanations, so hobbyists can recreate and adapt the device.