Matrix Hub

An embedded Rust application for the Adafruit MatrixPortal S3 that drives a 128x32 HUB75 LED matrix display with WiFi-connected apps including NYC MTA subway arrivals, plasma effects, and physics simulations.

Features

Hardware Support:

• Adafruit MatrixPortal S3 (ESP32-S3 based)
• 128x32 HUB75 RGB LED matrix (4-bit color depth)
• LIS3DH accelerometer via I2C (STEMMA QT connector)
• Two physical buttons (UP/DOWN) for app rotation
• WiFi connectivity with async HTTP/TLS client
• Optional: 3D printable enclosure by Pavel Smalec

Apps:

• MTA - Real-time NYC subway arrival predictions from GTFS-RT feeds
• Plasma - Animated plasma effect visualization
• Sandbox - Physics simulation with accelerometer-based gravity

Runtime:

• Dual-core async execution using Embassy
• Core 0: WiFi, apps, HTTP server, SNTP time sync
• Core 1: Display rendering at ~50 FPS, HUB75 DMA refresh at 500+ FPS
• Automatic app rotation with configurable intervals
• Web-based configuration interface on port 80
• Persistent configuration storage in NVS flash

Building & Flashing

Prerequisites:

• Rust with ESP toolchain (see rust-toolchain.toml)
• espflash CLI tool: cargo install espflash

Build and flash:

# Create a .env file with your WiFi credentials
echo 'WIFI_SSID=YourNetworkName' > .env
echo 'WIFI_PASSWORD=YourPassword' >> .env

cargo run --release

The .env file is loaded at build time and used as the default configuration.

Windows users: You need to attach your USB device to WSL before flashing:

# In PowerShell as Administrator, find your device bus ID:
usbipd list

# Attach it (adjust bus ID as needed):
usbipd attach --wsl --busid 1-1

Configuration

Initial Setup

Create a .env file in the project root with your WiFi credentials:

WIFI_SSID=YourNetworkName
WIFI_PASSWORD=YourPassword

These values are loaded at build time and used as the default configuration. The .env file is git-ignored for security.

Web Interface

Once connected to WiFi, access the configuration web interface at the device's IP address on port 80. The interface provides:

• Main landing page with navigation
• Interactive JSON configuration editor with live validation
• Real-time device state viewer

Configuration changes made through the web interface are automatically persisted to flash storage and will survive reboots.

Manual Configuration

You can also edit the default configuration in src/bin/main.rs before building.

Demo