This was very easy to use. I wanted to monitor the volume of sound coming from my furnace and send IR signals to my TV speakers. The envelope setting was a very easy way to get the volume level of sound. I also looked at the audio and gate options which were equally as easy to use.

I had first tried to use a MEMS microphone breakout and had some difficultly because the voltage range was very low between high and low volume. That microphone would also drift in readings so I had to make rolling adjustments. I did learn a lot from struggling with that microphone.

I think if you are getting started and not familiar or ready for making amplifiers or making adjustments to readings, this is a very nice option.

This guy is just what I needed. It found it a little too sensitive, which I consider better than not sensitive enough.

I bought this board to measure low amplitude sound on an oscilloscope, so I am using only the audio output at this point. I particularly liked the extensive documentation that SparkFun provides around gain adjustment. Since I wanted to boost the gain above 100X, I desoldered and removed R3 and added a two pin header to R17. Then I was able to mount the detector on a breadboard and wire a 100K resistor in series with a 1 MegOhm potentiometer to give me continuously variable gain from 100X to 1000X. It works very well!

Take note of SparkFun's advice about providing the detector clean 5V power. I was using what turned out to be a very noisy modified cell phone charger for power and that was causing problems as the documentation pointed out. I switched to a battery pack and that made a big difference.

This is a really useful board. The only improvement I could suggest would be to add variable gain control on-board, but it is really easy to do it yourself on a breadboard.

Great little circuit. Used them before and they are reliable and easy to use.

Much better frequency range than the MEMS device, excellent signal. Caveats: 1. VCC isolation is necessary if one employs frequency filtering of the analog output. Best to sacrifice a diode drop in voltage to prevent instability of downstream filters. 2. The literature states that it should be operated at 5V for best performance, but I have blown up two devices at this operating voltage with a DC bench power supply; I believe it is sensitive to inrush current. Put a current choke in the VCC path.

I take out the microphone and directly wire in audio. I use the audio envelope as an input to an Arduino. Lowered the gain with a 20K resistor.