Hello, all! This is my first post as a member of the Particle community.
I’m working on a small project that alerts me if the noise in a room surpasses a certain level. I’ve tried a wide variety of microphone systems to make this work, and none of the ones that I’ve put together seem to do what I’d like them to do.
The system I have in mind provides 3.3V to a microphone module, which will output values to the Spark via one of the analogue pins. However, the systems I’ve purchased and assembled, such as the MAX4466, the op-amp design here, and a circuit very similar to this one, found here.
All of these devices output SOME voltage in the way that I’m hooking them up, but none of them seem to respond very much to changes in volume. On the 0-4095 scale that AnalogRead() pulls up (that I’m monitoring from my desktop using direct requests to the Core) no matter how much noise I make at the electrets, the value only seems to fluctuate within a range of 5 or so. I’ve tried feeding the MAX4466’s output through an op-amp subtractor to try and get rid of the ‘offset’ caused by a quiet room and then multiply the output of that by 100x to see if the changes are just too tinny to register without massive amplification, but that also doesn’t seem to be working.
Has anyone ever used electret mics with a Core? Do you have any tips, any suggestions on why what I’m doing isn’t working out?