ESP32 Firmware Guide

Build, customize, and update the RoastIQ firmware.

Project Structure

Roasting_intelligence/
├── src/
│   └── main.cpp          # ESP32 entry point, WebSocket server, sensor reading
├── include/
│   ├── temperature.h     # isValidTemp(), RollingAverage<N>
│   └── telemetry.h       # buildTelemetryJson()
├── test/                 # Unit tests (run with pio test -e native)
├── platformio.ini        # Build environments
└── docs/                 # Documentation

Build Environments

Build and Flash

# Development build
pio run -e dev --target upload --upload-port /dev/ttyUSB0

# Production build
pio run -e esp32doit-devkit-v1 --target upload --upload-port /dev/ttyUSB0

# Monitor serial output
pio device monitor --port /dev/ttyUSB0 --baud 115200

How It Works

Initialization:

1. Create WiFi access point named RoastIQ
2. Start WebSocket server on port 80 at /ws
3. Initialize two MAX6675 sensors via SPI

Main loop (4 Hz):

1. Read raw BT and ET from MAX6675 sensors
2. Validate temperatures (0.5°C – 1000°C range)
3. Apply 5-sample rolling average for smoothing
4. Send JSON frame via WebSocket

WebSocket protocol:

Request from Artisan:

{"id": 1}

Response from ESP32:

{"id": 1, "data": {"BT": 185.5, "ET": 210.25}}

Unit Tests

Run tests without hardware:

pio test -e native

Downloads

Troubleshooting

ESP32 won’t flash: Hold the BOOT button while pressing EN (reset). Release BOOT after upload starts.

Permission denied on /dev/ttyUSB0:

sudo usermod -aG dialout $USER
# Log out and back in