There is now a better way to save full resolution mic samples to external SD Card or the internal filesystem (credit to @MikeShi42 on github for this implementation). Please take a look at the new example#5 in the I2S usage guide. Compared to my previous post, this example uses 1/2 the DMA memory and does not require a prune() function.Dogostyle wrote: ↑Fri Feb 08, 2019 4:58 pmI have some questions though, why you decimate or prune your samples before saving into the SD?. And, how can I achieve full resolution (18bits) from the mic (https://cdn-shop.adafruit.com/product-f ... asheet.PDF)?
The I2S guide also has a new example#4 describing how to use an I2S Microphone based on the INMP441 device (again, credit to @MikeShi42 on github for developing this example). The INMP441 I2S Mic is likely a better choice than the Adafruit I2S Mic which is based on the SPH0645LM4H device. Unfortunately, the SPH0645LM4H device was designed with non-standard I2S timing and appears to have some limitations when used with the ESP32 micro (and possibly other microcontrollers that support an I2S interface). I'll make a detailed post outlining these limitations in the near future.