Low Cost Stand-Alone Clap Only Detector

Clap-clap switches find applications in various domains such as automation and security. A clap sound can be used as a triggering signal either to switch the relays on/off, or as an alert signal for security system. However, the sound is very directive and sensitive to noise floor. Also, being an impulse, it is difficult to distinguish between a clap and other similar impulsive sounds like bang, dog-barking, coughing, etc. We propose a device for detecting clap sound which can also distinguish it from other impulsive sounds. We have used band-pass filtering in frequency domain and correlation in time domain to effectively detect and distinguish clap sound from other sounds.