Find specs for LM393 Sound Detection Sensor Module

I've purchased a LM393 Sound Detection Sensor Module electret microphone to use in a project, but I cannot find any specs for this device. Nowhere on the Internet can I spot something like a datasheet. Does anyone know where to find the information for this mike. I would be grateful.

Sometimes you get what you pay for...

If you buy from a reliable supplier you should be able to get the specs and/or datasheet before you buy, so you know what you are buying and how to use it.

The [u]LM393 IC[/u] is a [u]comparator[/u]. The output from a comparator is digital and it should go to a digital input.

That doesn't tell you anything about the circuit on the board, but the comparator's output should go momentarily high when the sound is louder than the threshold setting.

Use the serial monitor to monitor the Arduino's digital input that you've connected to. Adjust the pot while there is sound (or put the thing in front of a speaker) to see what happens... Hopefully, you can make it "trigger" with loud sounds and refrain from triggering with quiet sounds or silence.

Thanks DVDdoug, for your reply. I knew that though. And yes, I agree: for $ 2.71 you can't expect that much. I was looking for wiring schema's and I was wondering what the output is of the audio channel of the mike. I'll keep on searching for a datasheet.

What are you trying to do with this board? If you want to detect sound and turn-on a light, or blink a light or LED to the music, this board should help you do something like that.

I was looking for wiring schema's and I was wondering what the output is of the audio channel of the mike.

You'd also have to know how loud the sound is. Do you know that? Do you have an SPL meter? (sound loudness meter)

There's an audio signal out of the mic, but there is no "audio channel" out of this board.* The output of a comparator is digital (not analog). It's 5V (approx) when triggered and 0V (approx.) when not triggered (assuming a 5V power supply).

If there was a published spec for the mic itself, it would be a "sensitivity" spec (such as 100mV @ 90dB SPL).

Since this is a PC board with an adjustment-pot and (apparently) a comparator-output, there would simply be a sensitivity range (such as 70-90dB SPL).

  • I'm only 99% sure of this, since we don't have any specs or a schematic.

Hi DVDdoug,

Indeed, I'm trying to do something like detecting sound and blink a LED. Just for experimenting purposes for now. I don't have an SPL meter, but the sound is just plain speak, maybe a little loud plain speak. I know the output is a digital value. In the Serial Monitor I'm reading values of around 28 (digital output of comparator, i.e. Arduino pin) when there is silence and 1023 (max. digital output) when there is sound. But sometimes I read value in between, which seems strange, as the sound sensor should only give HIGH (1023, sound) or LOW (around zero, no sound) pin values; maybe the digital output is dependent on sound input. What's more: I have to speak in the mike at very close distance. It looks like this mike is not very sensible.

Attached to a digital input the sound sensor makes the pin go LOW when sound is detected. Otherwise the pin is HIGH. The thing is: there is a small LED on the sensor which lights up when the sensor detects sound. This light turns on frequently when sound is made, but the Arduino digital pin doesn't allways pick up the sensor's output. So my guess is, that the sensor's output voltage is too low for the Arduino. An amplifier should be able to fix this.

I've attached an oscilloscope to this mike. It shows only HIGH (5V, silence) and LOW (0V, sound). So the mike doesn't output voltages in between. Further more, the mike isn't very sensitive: 30 cm is the maximum range from which it picks up sound. OK for some projects, not so for others.

Hi. I got similar sensor and also was hard to find the datasheet. But after spending about an hour &here you are

I've attached an oscilloscope to this mike. It shows only HIGH (5V, silence) and LOW (0V, sound). So the mike doesn't output voltages in between.

What possible other output did you expect from a comparator chip?

I saw TWO outputs on the module. Audio out, directly from the microphone. Can be use on A-in. Probably very low amplitude. And digital out, from the comparator. Use on a digital in. The pot sets the bias voltage/trigger point. Not the gain. Leo..

heaven_rover, Thanks for searching for the data sheet, but as you may have noticed from my link, I have a 3-pin module and yours is a 4-pin.

I just got here from Google, searching for the schematics of this (4-pin) module because of the lack of any significant analog output.

But it happens the conclusions above are premature, the opamp/comparator can be used to amplify the sound. Just put a resistor (or trimpot) from the D-output to the A-out (which is actually an input). Now the opamp will amplify.

The resistor determines the amplification, the suggested initial value is 10k, or use a 47k trimpot. Put the onboard trimpot in the middle position (make sure to never make it short to VCC).

Succeeded? report here :)

@heaven_rover sir I have got the sme module. i was previously working on analog input but its behaving unpredictable that i cant set threhold. And when i use D0 to Din its giving continous 0 :( could anyone help how can i uuse it with A0 or at least D0 but sound must be detected..