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Topic: Testing a new sound sensor. (Read 1 time) previous topic - next topic


May 01, 2014, 09:10 pm Last Edit: May 03, 2014, 12:08 pm by kaizokuj Reason: 1
Hi! My name is kaizokuj and I bought an arduino starter kit about a month ago and since I've been playing around with it almost daily. Recently I bought my first part that was not from the kit! I bought a sound sensor but I can't seem to get it to work.. I've made a post before on reddit but didn't get much response, so I'll just quote my original post  if that's alright!

So today I went and bought the first extra part since I got my kit about a month ago, A sound sensor, http://www.kjell.com/sortiment/el/elektronik/mikrokontroller/arduino/ljudsensor-for-arduino-p87888

On that site there is a link to some example code but sadly no schematic for the example they gave so I improvised: http://imgur.com/JmabbwG

The code they gave is this: http://pastebin.com/xR6Pprgz

However when I run it and check the serial output it's showing an almost constant analog output of 26-30 and a digital output of 1 no matter how much noise I make, what did I do wrong?
EDIT: Found this international link: http://eud.dx.com/product/arduino-microphone-sound-detection-sensor-module-red-844135533#.U1vgWtxtrZI

Thanks in advance for the help :)


No schematic and no hook-up diagram is sort-of a BIG PROBLEM! ;)   

You should only need 3 connections: Power, Ground, and Analog Out.    I assume the + pin is power (+5V) and it looks like you've got it going to ground. 

I see the LED is on so the board is getting power, but I have no idea if it's getting powered correctly.  If you hook-up something like this wrong, there is always the possibility of destroying it.


Here's a page with some reviews of what appears to be the same product:  http://club.dx.com/reviews/text/135533.  From what the reviewers say, the output is unamplified, and the single integrated circuit on the board is a comparator rather than an amplifier.  Conventional wisdom says you need amplification on the order of 100X with an electret, on a 5V system.  In order to use it meaningfully, you will probably have to add an op amp.  You can see how sparkfun did it, here - https://www.sparkfun.com/datasheets/BreakoutBoards/Amplified-Mic-v10.pdf


May 02, 2014, 09:10 am Last Edit: May 02, 2014, 09:12 am by kaizokuj Reason: 1
Yeah sadly no schematic was on the website that had the code..
A guy in the reddit thread said that one of the components on the sensor can and most likely does act as an amplifier.
Here is the original post:


As for the LED, if I take down the threshold from it's original value (400 something) it lights up. So I think it should be working as it should, however the sensor doesn't even increase a little no matter how much noise I make.

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