Sound Detection With The Arduino

I decided on Saturday that I’d try my hand at building a setup with the Arduino to detect sound. I found the perfect schematic online here from the guys over at SparkFun.com. They have a really nice breakout board for an Electret Microphone but it’s ~$8.00 and I already had the stuff on hand to build my own. I think I’ll still pick one of theirs up at some point, just to have around. It’s quality built and tiny. I’ve attached the Schematic and the code with additional high-res pictures below for anyone more interested. I used an OpAmp to increase the voltage and had the code check for a threshold. Once the threshold had been exceeded, it would light up the red LED. The end result looks very similar to one of the old-school VU meters. You can adjust the gain on the amp by increasing the R5 resistor. This would make an excellent sound detector or even could be hooked up to a small speaker, it’s a simplistic mono-amplifier after all…