I bought one of these:

1Pcs New Sound Detection Sensor Module Voice Sensor for Arduino Best

There are 3 pins on it:

  • 5V
  • GND
  • OUT

My guess is that OUT is an analogue signal that I can measure with my Arduino, am I right?

I am using the "Analogue Output" example code but I just get 5V all the time, it does not seems to change with the sound levels.

Am I doing something wrong? What am I adjusting with the blue square on the board? Should I maybe do that?

  • Output should be +5V with no sound and 0V with sound. The AnalogInOutSerial example should display on your monitor wit values close to mx for no speech and close to ground for speech present. – Russell McMahon Feb 3 '15 at 5:40

The wording on this particular eBay item is pretty poor but there are plenty of similar products with better descriptions that are photographically identical... example that make a little bit more sense.

Anyway, I don't think this gives an analog value output, the LM393 is a comparator, so I think the blue dial sets the 'threshold level' and any sounds over that level cause a logic low. i.e. it compares the audio level and the dial and when one exceeds the other it gives a signal.

The features also say "The output effective signal is low level" which is probably Chinglish for the signal is a logic low, i.e. when the sound is heard it goes to 0V rather than 5V which is what I think you were expecting.

In summary: This device is is more like a Clapper, it detects a loud noise and sends a digital low signal.

Try making a loud noise with the same setup you already have, and if not try adjusting the potentiometer by turning it, but not too far! It probably only turns 180-270º.

  • Sound good, I will try to change potentiometer and check the output. Is it easy to turn it too far? – theva Feb 2 '15 at 23:50

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