Design and Construction of Clap Activated Switch

  IJETT-book-cover  International Journal of Engineering Trends and Technology (IJETT)          
© 2018 by IJETT Journal
Volume-60 Number-1
Year of Publication : 2018
Authors : Tomiwa A. C.
DOI :  10.14445/22315381/IJETT-V60P204


Tomiwa A. C. "Design and Construction of Clap Activated Switch", International Journal of Engineering Trends and Technology (IJETT), V60(1),33-40 June 2018. ISSN:2231-5381. published by seventh sense research group

A sound activated switch is a device that utilizes sound to control appliances. An example of a sound activated switch is the one that works by mere clapping of hand. This could be likened to the stopwatch system used in the international athletics competition which uses a gunshot to trigger it to start. Clap activated switch (CAS) is a simple type of control system that requires a clap to control e.g a lamp. This is able to be achieved because it has a microphone that picks up sound and a high gain amplifier that amplifies the sound to about 120times of its input level. The sound is now sent to one-shot monostable circuit that is configured to be triggered by a clap.The monostable circuit also acts as a Schmitt trigger as it converts the clap sound to a square pulse, sending it as a clock pulse to a D type flip-flop. The flip-flop causes a change in output latching it either ON or OFF. This latching is used to control light bulb, using a relay via a relay driver circuit.

[1] Tokheim (1994): Digital Electronics McGraw Hill International Fourth Edition, pages 139-140.
[2] Howard H. Gerrish and willaims E. Dugger (1984): Electricity and Electronics McGraw Hill Book Company Fourth Edition, Pages 120, 146, 168.
[3] Kevin F. Brennan Handbook of Electronics (1992): The physics of Semiconductor with Applications to Optoelectric Devices; Second Edition, pages 693.
[4] Sessler, G. M.; West, J. E. (1962): Self-biased Condenser Microphone with High Capacitance. Journal of the Acoustical Society of America 34: 1787-1788.
[5] V.K. Mehta (1998): Principles of Electronics Published by S. Chand and Coy Ram Nagar; Sixth Edition, Pages 390.
[6] Milton Kaufman, Authur H. Sheidman (1999): Handbook of Electronics Calculations for Engineers and Technicians McGraw Hill Company; Second Edition, Pages 10–12

Flip-flop, Monostable, Astable, Relay.