makerportal / rpi_i2s

Raspberry Pi I2S Stereo Microphone Analyses in Python

I²S Microphone Recording on Raspberry Pi with Python

Python codes that read, save, and analyze audio input from I²S MEMS microphones on a Raspberry Pi

Raspberry Pi boards are capable of recording stereo audio using an interface called the inter-IC sound (I2S or I2S) bus. The I2S standard uses three wires to record data, keep track of timing (clock), and determine whether an input/output is in the left channel or right channel. First, the Raspberry Pi (RPi) needs to be prepped for I2S communication by creating/enabling an audio port in the RPi OS system. This audio port will then be used to communicate with MEMS microphones and consequently record stereo audio (one left channel, one right channel). Python iS then used to record the 2-channel audio via the pyaudio Python audio library. Finally, the audio data will be visualized and analyzed in Python with simple digital signal processing methods that include Fast Fourier Transforms (FFTs), noise subtraction, and frequency spectrum peak detection.

The full tutorial can be found at: https://makersportal.com/blog/recording-stereo-audio-on-a-raspberry-pi

Mono Wiring

Stereo Wiring

Mono Output

Example Output for 557Hz Test Frequency:

Stereo Output

Example Stereo Output for 1012Hz Test Frequency:

rpi_i2s's Issues

questions about data normalization in the function of data_grabber(rec_len)

Thank you very much for your tutorials and codes.

I noticed that in the function of data_grabber(rec_len), after you got the raw data from the pyaudio stream, you did not normalize it by dividing 2**15 (say the format is np.int16). I want to know if you realized it and if there is a good reason of the current choice.

stereo audio recording with INP441 too noisy on one channel

In mono there is no problem, while in stereo, one channel is affected by a very high noise sound.In mono there is no problem, whereas in stereo one channel is affected by a very strong noise.