Build a Covert Bone Conduction Speaker and Radio That Fits In a Pen

Using a standard FM radio receiver and piezoelectric transducer, creatorBen Krasnowhas built the perfect clandestine listening unit.

Nobody else around you will have any idea that you’re listening to something.

Check out the whole video to see how he does it.

Covert radio pen with bone conduction speaker| YouTube viaHackaday