Sound sensor circuit diagrams

Whistle On - Whistle Off
December 29, 2010

This is an extension of the CMOS toggle flip flop circuit with the addition of two bandpass filters and condenser microphone so the relay can be toggled by whistling at it. The condender mic used... [more]

Sound Operated Switch
November 26, 2010

This sensitive sound operated switch can be used with a dynamic microphone insert as above, or be used with an electret (ECM) microphone. If an ECM is used then R1 (shown dotted) will need to... [more]

Room Noise Detector
November 15, 2010

This circuit is intended to signal through a flashing LED, the exceeding of a fixed threshold in room noise, chosen from three fixed levels, namely 50, 70 & 85 dB. Two Op-amps provide the necessary... [more]

Keys Finder
November 8, 2010

Imagine that is morning , you barely anticipate the bus for work and you can't find your keys. If you suffer from this situation frequently, this circuit is ideal for you. A fizzle is the... [more]

Voice activated switch
October 5, 2010

This circuit uses an MC2830 to form a voice activated switch ( VOX ). A traditional VOX circuit is unable to distinguish between voice and noise in the incoming signal. In a noisy environment, the... [more]

Whistle Responder
October 5, 2010

Some 15 years ago it was common to see small key-holders emitting an intermittent beep for a couple of seconds after its owner whistled. These devices contained a special purpose IC and therefore were not... [more]

Electronic Candle Blow Out Schematic
October 3, 2010

This design was developed by request of a correspondent having made a sort of LED candle and needing to switch off the LED with a puff. This simple, easy to build gadget can be useful... [more]

circuit from:http://www.extremecircuits.net/2010/01/electronic-candle-blow-out-schematic.html

Whistle Responder Schematic - Circuit Diagram
September 27, 2010

This device beeps intermittently for about two seconds when a person in a range of around 10 meters emits a whistle. The first two inverters contained in IC1 are used as audio amplifiers. IC1A amplifies... [more]

circuit from:http://www.extremecircuits.net/2009/12/whistle-responder-schematic-circuit.html

Room Noise Detector Circuit Schematic
September 27, 2010

This circuit is intended to signal, through a flashing LED, the exceeding of a fixed threshold in room noise, chosen from three fixed levels, namely 50, 70 & 85 dB. Two Op-amps provide the necessary... [more]

circuit from:http://www.extremecircuits.net/2009/12/room-noise-detector-circuit-schematic.html

Clap Sensitive On-Off Relay
September 27, 2010

This circuit was intended to activate a relay by means of a hand clap. Further claps will turn-off the relay. An interesting and unusual feature of this project is the 3V battery operation. The circuit's... [more]

circuit from:http://www.extremecircuits.net/2009/07/clap-sensitive-on-off-relay.html