Overview
The TinyUSB library underpins many of CircuitPython's USB capabilities. It's what lets CircuitPython act as a storage drive, CDC, HID, MIDI and more. Starting with version 10.3.0-alpha.3 CircuitPython has added support for USB audio types. This guide demonstrates how to use the USB microphone capability to generate tones and output them to a computer or other digital audio equipment. You can connect a basic key to tap in Morse code live, and use the generator function to automatically convert strings into beeps and boops.
Morse Code Key with 3.5mm Jack
Morse keys come in different shapes and styles, but all are electronically similar. They are a basic momentary switch that closes a circuit when you press the key, and opens the circuit when you release the key. They can be found easily in online shops and radio equipment providers, or DIY'd with a 3D printer, spring, and conductive contacts. I used this one.
Page last edited June 29, 2026
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