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--- doc:appunti:hardware:raspberrypi_abbaiometro [2015/12/10 15:22] – created niccolo
+++ doc:appunti:hardware:raspberrypi_abbaiometro [2015/12/10 15:34] (current) – niccolo
@@ Line 1: / Line 1: @@
 ====== Abbaiometro con Raspberry Pi ======
-===== Sound Sensor =====
+===== The Sound Sensor =====
-{{.:raspberrypi:sound_sensor.jpg?250|}}
+{{.: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 sound sensor, sold for about 3-5 €.
+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.
+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.
+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.