<antirez>
2 days ago
- The Raspberry Pico is a well-made, durable chip with a ton of features, including state machines for GPIOs, and its lack of connectivity is resolved by the W variant.
- The chip is well supported by MicroPython and the C SDK, though the build system is overcomplicated for small programs.
- To generate sound without a DAC, PWM can be used with a high frequency and varying duty cycles to approximate different voltage levels.
- A WAV file can be converted to raw 8-bit PCM at 24000 Hz using ffmpeg, then played on the Pico by reading the file and setting PWM duty cycles for each sample.
- The playback speed may not match exactly, requiring manual delay adjustments (e.g., adding dummy statements) to correct the pitch.
- MicroPython supports threading, which could be used to play audio in a separate thread to avoid blocking the main program.
- A simple sin wave can be generated by precomputing duty cycle values and looping through them.