The Mic Jammer is an ultrasonic security system that gives people the confidence to know that their smart phone microphones are non-invasively muted. This is a hardware not a software solution.

It blasts ultrasonic noise slightly above 20kHz out of an ultrasonic transducer at an iPhone MEMS microphone. This range very high-pitched, and slightly above the capacity of human hearing but still within the sensitive range of the mic.

This is a version of the EAGLE schematic used to build an ultrasonic mic jammer at EYEBEAM.

I'm sorry it's not more detailed, I have other versions on a computer that is broken so once I rescue the harddrive I will update it.

You can find more information about the art project here: Allison Burtch - Mic Jammer