If you suspect that someone is spying on you or recording your conversations with a hidden microphone, there are products on the market you can use to detect any unwanted microphones in a room. A bug detector or hidden microphone detector is designed to pick up the RF, or radio frequencies, in a room that a microphone will give off and is the tool you will want to use to find even the smallest hidden microphones.
Turn on the bug detector.
Sweep the room that you suspect of having a hidden microphone with the bug detector. Hold the detector away from your body and walk through the room checking anywhere that you could possibly hide a microphone, including the telephone, light fixtures, air vents and any nearby electronics.
Find the microphone's location using the signal strength meter on your bug detector if you pick up a signal. The closer you get to the microphone, the stronger the signal will get.