Sending audio over tcp using Electret Mic MAX4466

[jim3]

I've been using the Particle.io Microphone_PDM library to send audio over tcp to my node server (located on a live domain) with great results, already have some cool ideas for a node app...thankful for that library because without it none of that would be possible...

Regardless, I happen to pick up a "Electret Microphone Amplifier - MAX4466 with Adjustable Gain" with the MEM's mic as well just out of curiosity. So obviously I was curious if this was possible with Electret as well and found the library ADCDMAGen3_RK and got excited!

I installed the library ADCDMAGen3_RK compiled and got an error:

In file included from src/Electret-Microphone-MAX4466.cpp:1:
lib/ADCDMAGen3_RK/src/ADCDMAGen3_RK.h:9:10: fatal error: nrfx_ppi.h: No such file or directory
    9 | #include "nrfx_ppi.h"
      |          ^~~~~~~~~~~~
compilation terminated.
make[2]: *** [../build/target/user/platform-32-msrc/Electret-Microphone-MAX4466.o] Error 1
make[2]: Leaving directory `/firmware/user'

Doing some quick searches this looks like a nrfx driver? Do you think I need to install the module or library? Honestly, I have no idea though, when it comes to C++ I am totally lost. I am using the Photon 2.

[rickkas7]

That library only works with the nRF52840-based devices like the Argon and Boron.

It should be possible implement ADC DMA on the P2/Photon 2 (RTL872x) but I haven't attempted to do it.

It would require a completely different library, or a library that has two completely different implementations in it. That's how Microphone_PDM works; there's one implementation for nRF52 and one for RTL872x in a single library with a single API.

[jim3]

Thanks for the reply back and explanation. Personally, I'm fine with using the PDM mic and Microphone_PDM library...I have plenty of other options to use the Electret Mic MAX4466 in other ways.