He’s using an everyday LED as a detector diode and an internal pull ... across the LED will start to discharge. If there is an RF signal present, the discharge voltage will be less than the ...
It’s not so far-fetched though, while bugs and hidden cameras in for example an Airbnb may not have flashing LEDs, they still emit RF and can be detected with a signal strength meter.
They can be disguised in plain sight in a USB charger, smoke detector, or even on a television, watching your every move. Let Hidden Camera, Bug, GPS, and RF Detector keep you safe, sweeping for ...