Make a covert radio pen with bone conduction speaker

http://boingboing.net/2015/02/11/make-a-covert-radio-pen-with-b.html

My favorite maker of cool stuff is Ben Krasnow. He made an electron scanning microscope from scratch, and makes astronaut ice cream in his backyard laboratory. He's also a great explainer of how he makes he things. In this video, Ben explains how to make a covert radio pen with a bone conduction speaker.