Build a Speaker for Hidden Bone Conduction and a Radio That Fits in a Handle
Bone Conduction Speakers give you the ability to hear what no one else can by vibrating your own bones, and this hidden system, which fits perfectly inside the handle, can be activated by simply biting down on it.
Creator Ben Krasnov, using a standard FM radio and a piezoelectric transducer, created the perfect covert listening device. Just bite down on the tip of the pen and the speaker inside vibrates in your jaw, sending sound waves upward towards the cochlea in your ear. None of those around you realizes that you are listening to something. Krasnov notes that this could be used to cheat a test, transmit classified information, or – as a less “evil” use – could be placed in a CamelBak for outdoor music that won’t block or interfere with the environment. Watch the full video to see how he does it.
Concealed Radio Handle with Bone Conduction Speaker | YouTube via Hackaday