How can I sample audio and send data via ble on nRF52?

[stefano.luna]

Hi, my setup is:

• nRF52 DK PCA1040 v1.0.1;
• Adafruit MAX9814 electret microphone amplifier;

My project concerns about:

1. Sampling audio from the board with SAADC. A starting point could be, for example, 1s audio record every 15 seconds with 4kHz as sampling rate;
2. Perform the FFT of the data sampled;
3. Send the result by Bluetooth to Raspberry Pi in the easier way.

Now I am working at point 1 and I only built some SAADC example:

• SAADC Example from SDK13;
• The example form: devzone.nordicsemi.com/.../;
• The examples from: github.com/.../nRF52-ADC-examples;

I need to know which one is the best to modify and some tips to follow to reach our goal. Up to now I spent a lot of time to setup the environment, build and fix the examples and makefiles and run them. It would be really good to have some advice and a working trail to follow.

About points 2 and 3 we need only some suggestions on how to perform them in the best and more efficient way without wasting time in a lot of attempts.

Thanks

Best Regards

[endnode]

Slightly off-topic question: why to bother with such mic and ADC when nRF52 has I2S and PDM? Wouldn't be easier to use microphone compatible with these?

[stefano.luna]

I prefer to stay with the SAADC beacuse i think it consumes less energy, as i could read here devzone.nordicsemi.com/.../.

[endnode]

Right, power consumption can be bigger. It seems to have easier integration (at least I2S worked in nRF5 SDK for me) but if power consumption in the main criteria then you are probably going right way. Good luck!