This design idea showcases a circuit that detects RF “bugs,” such as hidden wireless cameras, eavesdropping microphones, and other spying devices that emit RF frequencies in the 100MHz to 3000MHz range. A modification to this circuit not only detects RF bugs, but also locates their hidden positions.
The circuit is based around the MAX2015 RF detector which outputs a voltage proportional to the strength of a received RF signal in the 100 MHz to 3 GHz range. This voltage can be detected with a comparator that activates a buzzer at a predefined signal strength.
If the comparator is replaced with a op-amp the circuit could be used to locate RF transmitters by increasing the buzzer volume as one comes closer the source.