detecting background noise

[Tripper269]

Recently I got a project to design intelligent master controller for washroom. Idea is with microphone controller should know when the activity is higher and low. So accordingly it can control lights, exhaust fan, dispensers etc. should I use FFT to differentiate the background or it’s possible with voltage level only. I am using Breakout Board for ADMP401 MEMS Microphone from sparkfun, Labjack UE9 and LabVIEW.

Please advise that which approach should i use

Thanks

[USBarnes]

Tripper269,

I think this is going to depend on how precise you need to be. Gathering frequency data through an FFT is going to give you information about what frequencies are picked up by the microphones, but you'll need filtering (Analog and/or digital) which could add more code or hardware while a straight voltage is going to be less hardware intensive and the algorithm will likely be easier to code as well. However, measuring only voltage may not be as precise as frequency data. Some preliminary testing may be wise to determine which of these methods will work best for your application.