Dual MEMS microphones, wrong readings

ESPHome
1

hi all,

I’ve got a strange thing going on. My goal is to measure environment noise. I want to do this with 2 seperate MEMS mics (43434) and two seperate ESP32 boards. I’m using stas-sl’s ESPhome sound level meter solution.
The two esp32’s go physically in a box and I like to mount them on top of each other. When I do that, I get noise level readings of 70+ dBA in a silent environment. If I disconnect on boards, the other gives proper readings (56dBA), also if I move the second board away from the first one, readings or good on both.

So, it looks like interference. What could cause this? connections to the MEMS mics are about 30cm of wire, no shielding. Both boards have no electrical connection and share the same usb power supply.

any ideas? Thx!

2

Why you want to use two?
I could imagine at least some disturbance on 2.4ghz if you stack them on top of each other.

3

I want to read north and south noise separately. And 2.4GHz is wifi, and there’s no problem with wifi. Connections are good, it’s the noise level itself that gets messed up:

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where the readings go up, I mounted them on top of each other

4

I’m not anyhow familiar with the component you use, and limitations it has so my question was why two ESPs. Doesn’t it allow two I2S microphones on same esphome setup?

5

aha, I use the esp32 C3, it only has 1 i2s input. the S3 has 2 i2s’s but the needed analysing software isn’t working properly on an s3