I want to develop an ultrasonic microphone array application. Is there a development board suited to this? The application would log recordings from 8 digital mems microphones to one or more SD cards.

[Tesla DeLorean]

How are the microphones going to interface?

Only a handful of the EVAL boards have dual micro-sd sockets, look at STM32F769I-EVAL

https://www.st.com/resource/en/user_manual/dm00276567-evaluation-board-with-stm32f769ni-mcu-stmicroelectronics.pdf

[DWall.2]

I think that 'how are the microphones going to interface' is my question. This is what I am trying to learn. I have read a bit about SAI and I2S. I'm looking for the easiest method to hook up 8 digital MEMS microphones and sample at quite a high sample rate. I am wondering if there is a development board that would be suitable for doing this. I would like to make a daughter board with my microphone array pattern and log the recordings. But I'm not sure where to start.

[Tesla DeLorean · Accepted solution]

Well stock boards are going to focus on more general features.

The EVAL boards for ST have a some large pin headers, but usage is often conflicted, and you might have to disable on-board functions to accommodate.

The DISCO boards have Arduino shield connectors, but anything not exposed on those pins is likely committed to other functionality.

The NUCLEO-144 boards likely expose everything you'd need to pin headers, but conversely don't have anything on-board to provide micro-sd, flash, external RAM, etc.

Yes, so figure the microphones you're using, find those which provide for the best serial, and multiplexed transport.

https://www.st.com/content/ccc/resource/training/technical/product_training/group0/d3/c0/b0/0e/fe/eb/40/a9/STM32H7-Peripheral-Serial-Audio-Interface_SAI/files/STM32H7-Peripheral-Serial-Audio-Interface_SAI.pdf/_jcr_content/translations/en.STM32H7-Peripheral-Serial-Audio-Interface_SAI.pdf

[DWall.2]

Thank you. This was useful. I have bought a NUCLEO H7 board to get started.

[Eleon BORLINI]

Hi @DWall.2​ ,

besides @Community member​ suggestions, please be sure to use a microphone with ultrasound capabilities, and that the sampling frequency of the processed signal is compatible with the ultrasound band.

-Eleon

[DWall.2]

Thanks. I will initially try with ICS-41352 microphones. I would ideally like to sample at greater than 192 kHz. But if I can log 8 channels, 16-bit, at 192 kHz it's a good start. Do you know if this will be possible with the two SAI ports on the NUCLEO-H723ZG? I could always use more than one microcontroller, and I have read that the SIA channels can be synchronised. It is of course vital that I have precise phase timing because I am using the array for directional measurement.