We want to record images of animals in a nature conservation project, and also birdsong: initially as audio clips on the SD card but later perhaps for processing onboard - see here, for instance: Birdsong analysis and visualisation | The Cacophony Project
In our case audio and video processing do not have to be simultaneous.
Cheap digital microphones are available, with the I2S interface.
Q1 - has anyone attempted to record sound on the OpenMV?
Q2 - are I2C pins available on the OpenMV?
Hmmm - I have found some background that might be of value if anyone wants this feature…
I have never interfaced to digital audio products. I had heard of I2S (which is different from I2C) as an audio interface.
And the ST processor supports this interface. It seems it needs three pins: in effect clock, data and sync (called WS).
When WS is low the left data is clocked out and when WS is high the right data. Microphone chips have a left/right select pin,
so if you want stereo you can connect two chips in parallel with their selects wired differently.
From what I can see, The OpenMV camera can support I2S on the pins provided for SPI interface (possibly - is this right?):
PB12 = SPI2_NSS on JP1 pin 7 = I2S2_WS
PB13 = SPI2_SCLK on JP1 pin 3 = I2S2_CK
PB14 = SPI2_MISO on JP1 pin 2 = I2S2_SDI (audio in?)
PB15 = SPI2_MOSI on JP1 pin 1 = I2S2_SDO (audio out?)
If there’s an I2S interface on SPI2 then you just need to write a C driver and then you can support a Microphone. The STM32 hardware will take care of audio data reception.