I2S microphone (RX)

theronic
Posts: 3
Joined: Tue Mar 05, 2019 10:31 pm

Re: Megaphone example for ESP32-LYRATD-MSC

Postby theronic » Tue Mar 12, 2019 7:48 am

Hi BuddyCasino, I'm trying to get your megaphone example working on the ESP32-LYRATD-MSC, but I'm only getting silence. I've spent a few days trying to cross-correlate what's different in the get-started/player examples and the newer esp-avs-sdk, but I'm only getting silence. Do you perhaps have some pointers or code lying around for the LYRATD?
BuddyCasino wrote:
Thu Jul 13, 2017 11:25 am
You might want to take a look at my megaphone example.

BuddyCasino
Posts: 262
Joined: Sun Jun 19, 2016 12:00 am

Re: I2S microphone (RX)

Postby BuddyCasino » Tue Mar 12, 2019 8:56 am

Sorry no, I don't have a Lyra.

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fly135
Posts: 606
Joined: Wed Jan 03, 2018 8:33 pm
Location: Orlando, FL

Re: I2S microphone (RX)

Postby fly135 » Tue Mar 12, 2019 4:14 pm

felipeduque wrote:
Fri Feb 01, 2019 2:27 pm
Now, I've only managed to get perfect I2S sound for sampling rate 8 kHz. From my experience with other I2S drivers (for H3 boards), it's a matter of proper clock handling. Probably some I2S master clock is too slow - maybe it didn't expect any sampling faster than 8 kHz? Anyway, I did not delve into it.
Just for reference I've had no problems capturing at 16Khz. However, If you try to capture and send in the same thread I would expect to have performance issues.

I just ordered a LyraT from China. Expect to get it in a couple weeks.

John A

pataga
Posts: 39
Joined: Sat Aug 12, 2017 5:53 am

Re: I2S microphone (RX)

Postby pataga » Fri Nov 15, 2019 7:25 am

Hi,

Just in case you guys didn't see this already

https://hackaday.io/project/162059-stre ... microphone

It seems the SPH0645 timing is incompatible with the ESP32 i2s peripheral. The data transitions on the rising edge of BCK, just when the ESP32 is sampling the data.

They ended the post by saying the INMP441 mems mic is compatible with the ESP32, showing a captured data sample, here the BCK rising edge is safely in the middle of the sample data.

I just got an INMP441 breakout board from aliexpress, and can confirm BuddyCasino's megaphone code example in this thread works without any modification. INMP441 LRCK grounded for left channel only. I used a MAX98357a breakout board for output with default board settings : SD and gain pins floating, (L+R)/2 output.

But I need to record mic samples myself to see what sort of dynamic range I am getting.

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