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Sound Sensor With Onboard Relay Arduino Nano Shield

This sound sensor with Relay driver shield for Arduino Nano can be used to develop sound-activated ON/OFF switch or other projects that require sound senor. LM358 op-amp is used as the amplifier, 1st op-amp amplifies the microphone signal, and 2nd op-amp works as a half-bridge rectifier that converts AC signal into a DC voltage. This DC voltage is connected to analog pin A4 of Arduino Nano, further, this circuit has a comparator that provides High-level signal output and goes low as the sound is detected, this signal is connected to D4 Pin of Arduino Nano. The board provides a dual output, analog voltage as well as a digital output. The output of the sensor is normally high and goes low when it detects sound. PR1 Trimmer potentiometer is provided to set the threshold. PR2 Trimmer potentiometer can be used to set the sound sensitivity. On-Board 5V relay can be triggered using digital Pin D5 of Arduino Nano, Relay can drive a load up to 7Amps 12V DC or 230V AC. The circuit works with 5V DC and consumes approx. 50mA.”

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