Here's an interesting way to control an Arduino using data-over-sound, demonstrated by Chirp. They show how to use their SDK to send an RGB value to change the colour of a on-board LED. You may ...

The already-large family of Arduino boards is enriched with a new entry, the Arduino Nano RP2040 Connect, integrating the RP2040 microcontroller developed by Raspberry Pi Foundation with the u-blox ...