CrateDigger
Dig. Chop. Loop. Repeat.
Author: Popa Nicolae
GitHub Project Link: https://github.com/UPB-PMRust-Students/proiect-nicupopa
Description
CrateDigger is a portable sampler built around a Raspberry Pi Pico 2 and programmed using the Embassy framework in Rust. The device allows users to sample audio, playback predefined samples, and perform beat-making using a 16-step sequencer. It features a user interface with tactile buttons, a TFT screen with animations, and high-quality audio output via DAC and an integrated speaker. Ideal for music producers looking for a portable sampler/sequencer.
Motivation
I have always been passionate about music and beat-making equipment. When the opportunity to pick this project came up, I knew it was the perfect opportunity to blend the two things I'm passionate about.
My goal is to create a compact, DIY sampler and sequencer that allows musicians and hobbyists to experiment with sounds, create beats, and take their creativity anywhere.
This project is not only a technical challenge but also a personal mission to create a fun tool that I might use in the future.
Architecture
Raspberry Pi Pico 2
Role: Central microcontroller, manages audio processing, input/output control, and overall device logic.
Connections:
Display, Micro SD Card Module, DAC, Buttons, and Output components.
Display (ST7735R)
Interface: SPI
Connections:
- SDA (Data Line) connected to Raspberry Pi Pico 2 SPI pins
- SCL (Clock Line) connected to Raspberry Pi Pico 2 SPI pins
Role: Displays user interface, sequencing steps and device status.
Buttons
Interface: GPIO Connections:
- Connected to GPIO pins for controls (playback, recording, navigation, sequencing)
Role: Allows user input for sampling, playback, sequence control, and settings.
Micro SD Card Module
Interface: SPI
Connections:
- SCK (Serial Clock) connected to Pico SPI pin
- MOSI (Master Out Slave In) connected to Pico SPI pin
- MISO (Master In Slave Out) connected to Pico SPI pin
- CS (Chip Select) connected to Pico GPIO pin
Role: Stores audio samples, sequences, presets, and configuration data.
DAC (MAX98357A)
Interface: I2S
Connections:
- Connected via I2S interface pins on the Raspberry Pi Pico 2
Role: Converts digital audio signals to high-quality analog audio for speaker output.
Output (Speaker)
Role: Outputs audio signal from the DAC to provide sound playback.
Log
- Week 5 - 11 May:
WIP... - Week 12 - 18 May:
WIP... - Week 19 - 25 May:
WIP...
Hardware
- Raspberry Pi Pico 2 (RP2350): Main microcontroller handling audio processing and system logic.
- I2S DAC – MAX98357A: Converts digital audio signals to analog for high-quality speaker output.
- ST7735R display: Colored screen for animations.
- Speaker: Outputs audio playback.
- Two potentiometers: For adjustable controls (volume/effects).
- Buttons: Input for interraction with the device.
Schematics
Bill of Materials
| Device | Usage | Price |
|---|---|---|
| 2x Raspberry Pi Pico 2 W | The microcontroller | 80 RON |
| ST7735R Display | OLED visual interface | 29 RON |
| MAX98357 I2S DAC | Audio output module | 24 RON |
| 4 Ohm Speaker | Sound playback | 40 RON |
| Consumables (buttons, potentiometers, wires, etc.) | Various components | 50 RON |
Software
| Library | Description | Usage |
|---|---|---|
| embassy | Asynchronous embedded framework for Rust | Core framework for running async tasks on the Raspberry Pi Pico 2 |
| embassy-rp | Embassy HAL for RP2040 | Hardware abstraction layer for the Raspberry Pi Pico 2 |
| embedded-hal | Hardware Abstraction Layer (HAL) traits | Provides unified interfaces for hardware drivers |
| embedded-graphics | 2D graphics library | Used for drawing to the ST7735R display |
| st7735-lcd | Rust driver for ST7735 display | Controls the ST7735R display |