Raspberry Pi Pico digital synthesizer board with stereo I2S audio (ADC & DAC), stereo omnidirectional MEMS microphones, MIDI i/o, a 16-key capacitive keybed, 1602 display, 2 rotary encoders, and LiPo battery charging and power distribution. Designed for use with CircuitPython and synthio.
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- PCM5102 I2S DAC with line output
- PCM1860 I2S ADC with line and microphone input
- PAM8019 amplifier with stereo class AB headphone and class D speaker output
- LiPo Battery usb charging and power supply controlled by 3v3_enable
- MIDI input and output via MIDI TRS-A 3.5mm jacks (compatible with most adapters)
- Input level potentiometer (line input only)
- Amplifier volume potentiometer (line output not included)
- 16 capacitive sense touch buttons powered by the TTP229-BSF
- 16x2 LCD character display
- 2 rotary encoders with push switches
- Micro SD card storage
The pico_synth_sandbox is designed for use with CircuitPython and synthio. A specialized library with hardware abstraction and a multitude of additional features for embedded audio synthesis is available in the pico_synth_sandbox repository. Library documentation and other resources are available on Read the Docs.
A number of hardware tests are available within the ./tests directory to validate the pico_synth_sandbox hardware using the REPL serial terminal.
Some pins require solder jumper configuration if you do not use the default pin assignment for MIDI & I2S.
| Pin Reference | Assignment | Direction | Function |
|---|---|---|---|
| GP0 | SD Card RX | Input | SPI0 |
| GP1 | SD Card CS | Output | SPI0 |
| GP2 | SD Card SCK | Output | SPI0 |
| GP3 | SD Card TX | Output | SPI0 |
| GP4 | MIDITX | Output | UART1 |
| GP5 | MIDIRX | Input | UART1 |
| GP6 | 1602 Enable | Output | GPIO |
| GP7 | 1602 Reset | Output | GPIO |
| GP8 | ADC Serial Clock | Output | I2S |
| GP9 | ADC Word Select | Output | I2S |
| GP10 | ADC Serial Data | Input | I2S |
| GP11 | Encoder 1 A | Input | GPIO |
| GP12 | Encoder 1 B | Input | GPIO |
| GP13 | Encoder 1 Switch | Input | GPIO |
| GP14 | TTP229 Serial Data | Input | GPIO |
| GP15 | TTP229 Serial Clock | Output | GPIO |
| GP16 | Encoder 2 A | Input | GPIO |
| GP17 | Encoder 2 B | Input | GPIO |
| GP18 | Encoder 2 Switch | Input | GPIO |
| GP19 | DAC Serial Clock | Output | I2S |
| GP20 | DAC Word Select | Output | I2S |
| GP21 | DAC Serial Data | Output | I2S |
| GP22 | 1602 D4 | Output | GPIO |
| GP26 | 1602 D5 | Output | GPIO |
| GP27 | 1602 D6 | Output | GPIO |
| GP28 | 1602 D7 | Output | GPIO |
- Project inspired by todbot/pico_test_synth