The sound sensor circuit has a function to conduct electricity based on sound detection to turn on the device connected to the circuit. Actually, the working principle of the circuit is almost identical sound sensor and a touch sensor circuit similar to that commonly used in devices such as mobile phones, laptops and notebooks. Both series also sound sensor and touch sensor using ic 555 monostable components. This component is used to determine the length of time the alarm will be active after getting a delivery of the trigger in the sensor area.
Ic component 555 can be replaced with other components such as alarms and lights. But the alarm circuit and the lamp will instantly die when the sensor input on the back changed.
On the image sensor circuit schematic of the noise, use a mic or microphone in charge to change the sound into electricity . Burning electricity generated is alternating waves and also has a very small voltage value . Alternating waves or so-called sinus will be supplied to the capacitor C3 which will be amplified by the transistors Q1 and Q2 . And the collector of transistor Q2 will be coupled with a monostable trigger circuit .
On Q2 collector circuit and also the circuit ic 555 are arranged parallel , the voltage magnitude will result in koletor this area will be reduced . If not installed in parallel , the collector voltage of Q2 will receive the same amount of supply due to flow from the emitter Q2 receiving delivery . Therefore Q2 collector will provide the state with a high voltage on the input pin 2 ( monostable ) . If time voice signal from the voice input sensor is quite saturated , then the value of the voltage at the collector will be changed to 0 volts . This condition makes the circuit monostable circuit will activate the output at pin 3 is determined by R1 and R2 components . The following components that you can use to make the sound sensor circuit :
1. ic 555
2. Transistors: Q1, Q2 and Q3 entirely bc 541
3. Resistors: R1 (100k), R2 (100k), R3 (10k), R4 (1k), R5 (1k) and pot VR 1 (100k)
4. Capacitors: c1 (220 μf), c2 (0. 01 μf) and c3 (100 μf)
5. Diodes: d1 (in 4001)
6. Relay 9 volt
8. Alarm circuits (according to taste)