Author Options:

Sound Locator Circuit? Answered

Hey all,

Here's an idea maybe one of you solder-jockeys can help me out with:

Ever have a sound that you'd like to find the source of, but your ears can't tell you where it's coming from?  I'd like to build a circuit to do that.

I was thinking of something like three electret microphones with op-amps between them in differential mode.  That would give three signals that would be, presumably, the ratio of sound coming from each mic.  (And, therefore, an indication of direction.)

Of course, I'd also like to get an adjustable bandpass filter in there somewhere to isolate just the sound I'm looking for.  That's the part that complicates all designs I've thought of.

And then, if I could somehow figure out distance too, that would be the ULTIMATE!

Here's one possible use case:
A car makes a funny squeal noise a highway speeds.
The mechanic takes out this device and magnets it inside the hood.  He runs a control wire back to the cabin.
Once the car is in motion and making the desire noise, he adjusts the BP filter using potentiometer(s) and a pair of headphones.
The device tells him where (relative to itsself) the sound is coming from.
Your bill is less because the problem was diagnosed quickly without a lot of guesswork.



The forums are retiring in 2021 and are now closed for new topics and comments.

2 years ago

Ggom20's idea for three undirectional microphones and a simultaneous recording or uP should locate in 2D space.. Use four to locate sound in 3D volume.


Reply 2 years ago

ok ! thats right as 3 points define a plane


2 years ago

The "easiest" way is probably computed sound analysis.

3 mikes is a good start.

If the question is really about cars, use one ore many microphones with

long wires and a mix table , so you can locate noise origin, .

The same is possible with wireless mikes.

Experienced mechanics don' t really need it, but i admit that it could be useful.

Roll Royce mechanics are known to use a stethoscope.

Some good Machinists knows about cutting edge state just by the noise.