My latest project is the RF detector wristband. It is a wearable electronics project that indicates if RF transmitters are working.
It uses a simple 2 diode detector circuit and a transistor to amplify the demodulated signal and drive the LED.
It works well on mobile phones and UHF transmitters. I built the circuit into a wristband because it gives you a free hand when you're testing a transmitter unit.
The battery is fitted into a pouch that uses the 2 button clips as battery terminals.
It all fits together, with the battery pouch under the circuit and the antennae located in the arm bands.