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====== Abbaiometro con Raspberry Pi ======

===== The Sound Sensor =====

{{.:raspberrypi:sound_sensor.jpg?direct&300|LM393 based sound sensor}}

I used a sound sensor based on the **LM393** comparator IC. It is advertised as an Arduino KY-038 Microphone Sound Sensor, sold for about 2-5 €.

==== Usage ====

Connect the **+** and **G** pins to **5 VCC** and **ground** respectively: the L1 LED should turn ON. It seems that the sensor works also at **3.3 VCC**, beware thet changing the voltage requires a new threshold regulation.

The **L2 LED** will turn ON when the sound level is above the threshold, which is regulated with the **trimmer potentiometer**. The POT is a multi turn (may be 10?) potentiometer: turn the mini screw **clockwise** to be **more sensible** (to lower the threshold) until the L2 stays ON at normal room noise, then turn the screw counter-clockwise until the LED goes OFF. Clapping your hands you should see the L2 LED blink.

When the sound is above the threshold, a digital **high signal** is sent across the **DO** (digital output) pin.