By: Arti singh gupta
Utilizing this sound activated switch, toggling a system by sound pulse could be
very effective, not simply on a robot but as well as for some kind of home
automation, as an illustration a sound-activated light bulb answering to a
topple on the front door or a a hand clapping action.
The lighting is going
to be promptly switched off after several seconds. An optional implementation is
security protection system when someone aspires to break open the front door or ruin
a thing, the light bulb may be expected to come ON on, indicating that someone uninvited is
at your home.
The circuit could work from any 5-12 VDC controlled power source
as long as a relay with the appropriate coil voltage is employed.
As soon as you first associate the source voltage to the sound
activated switch circuit, the relay will likely be energized on account of the
impact of capacitor C2.
You must permit a couple of seconds for the relay to be flipped
off. It is possible to maximize or minimize the ‘on’ time frame by modifying the
A larger uF contributes to an extended ‘on’ span, and the opposite way
round. However, you should not employ a value exceeding beyond 47μF.
resistor R1 establishes to a significant degree the microphone level of
responsiveness. An electret microphone commonly possesses just one central FET
inside which demands a bias voltage to run. The best possible bias degree
for response to audio or noise level must have to be discovered by
All of the related and useful electronic protection
precautionary measures is required to be recognized each time while connecting
mains powered loads to the relay contacts.
Parts List for the proposed sound activated relay switch circuit
R1 = 5k6
R2 = 47k
R3 = 3M3
R4 = 33K
R5 = 330 OHMS
R6 = 2K2
C1 = 0.1uF
C2 = 4.7uF/25V
T1, T2 = BC547
T3 = 2N2907
D1 = 1N4007
Relay = coil voltage as per the supply voltage, and contact rating as per the load specs
Mic = electret condenser MIC