Remember when Sony outed its PCM-D1 digital audio recorder and charged $2,000 ... Sony also tossed in a built-in speaker, a 5-second pre-recording buffer, digital limiter and the ability to ...

Part of what makes this all work is I2S (Inter-IC Sound), a format for communicating PCM audio data between devices. Besides the ESP32, at the heart of it all is an SD card reader breakout board ...