Device: RAK18032 + RAK11200 + RAK19007
I need to use 18032 to record ultrasonic sounds. The microphone produces PDM data and how can I analyse (and save) it in Serial Port (maybe using Python) (-> convert it to .wav for playing)
Also, I am curious about the sampling rate of PDM. In the example of
RecordToSD, the data_size is defined as frequency * BIT_PER_SAMPLE * duration / 8. I use part of the code and print buf to the serial. But it does not run
duration(s). I am curious about the meaning of frequency and BIT_PER_SAMPLE.
Furthermore, may I know if I can use I2S to get the data of microphone and how can I do it.