We have all been in a situation where we wished some obnoxious person, or group, would just quit talking, but there was nothing that could be done about it. That may be in the past. Japanese researchers Kazutaka Kurihara (from the National Institute of Advanced Industrial Science and Technology) and Koji Tsukada (from the Ochanomizu University) have designed a device called the ‘SpeechJammer.’ This device nullifies a person’s speech.
The gun uses a microphone that records the target talking and after a delay of only a few micro-seconds, sends it back to the target through a speaker which cancels out the sound. Fixated on top of the Jammer is a laser pointer to help target a person’s mouth and a distance sensor that helps in calibrating the delay needed for ‘feedback’. At its heart are a PIC18F152 and a BU9262AFS Audio IC commonly found in Karaoke machines for digital echo effects.
SpeechJammer and block diagram (via design paper)
However, the way it works is more psychological than technological in that most people feel uncomfortable when hearing themselves talk (like hearing a recording of your voice) and then cease talking after they’ve heard their own voice. Early tests showed that the SpeechJammer works best when someone is reading from a book, or other written text, at a distance of about 98 feet. The device is completely harmless to the target and can actually help people who stutter improve their speaking capability. Therapists have often used auditory feedback (same principal that the SpeechJammer uses) as a way to improve stammering in both adults and children. Now if it could only work through walls and quiet my neighbors down!