Audio recording support not available

[Muhammad Munir]

Dear All,

I am new to using Nordic boards. I want to connect MAX9814 microphone module with nRF51 DK board to record the audio of human. I could not find supporting libraries to get my audio recorded. It seems I may have to write own libraries which is beyond my expertise right now. 

Can you please guide me if there is any support available? I want to record audio in .mp3 or .wav format. 

[Stian Røed Hafskjold]

Unfortunately, we do not have any examples or libraries for this. The nRF51 does not have an ADC with DMA, so it would interrupt the sound sampling when it has to do other stuff, like softdevice interrupts. It's probably possible to implement something custom, depending on your use case.

I would recommend you to check out nRF52 and maybe a digital microphone instead. nRF52 has PDM and I2S digital interfaces, and also a much faster ADC with DMA if you want to use an analog microphone. You can check out the Smart Remote 3 reference design which has examples for this and also integrates the Opus sound codec.

[Muhammad Munir]

Thank you for the answer.

If I move to nRF52, do I still need to write custom library or any support available?

[Stian Røed Hafskjold]

You need to write a custom library if you stick to an analog microphone and ADC. It should be fairly straight forward though. If you use a PDM microphone we have libraries for this. Our Smart Remote 3 reference design already implements this functionality, and the code is open source. Please check out, http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sr3nrf52.firmware/audio.html?cp=9_3_1_2_1