I2S microphone (RX)

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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.

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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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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

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Re: I2S microphone (RX)

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


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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Re: I2S microphone (RX)

Postby Tnarain5 » Wed Jan 01, 2020 1:15 pm

Thanks all for your support!

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Re: I2S microphone (RX)

Postby Tnarain5 » Mon Feb 10, 2020 7:24 am

Hi guys,
i tried reading and writing at the same time using two different i2s_config, (using as an amplifier) for output im having real_rate 502 and required rate 8000 causing echo and noise, can you help !!

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