Coffee Roaster Controller

Safety-oriented embedded coffee roasting controller built on Zephyr for the NUCLEO-F767ZI reference platform.

The current implementation is an architectural reset checkpoint:

• MAX31865 temperature input is isolated behind temperature_sensor_read().
• Heater output is isolated behind heater_set_demand(). The default backend is still the NUCLEO LED mock; the hardware target is now a RobotDyn 16A/600V AC dimmer module using ZC and PSM pins.
• Safety logic owns final heater permission.
• Application telemetry is transport-independent and emitted as CSV on the Zephyr console.

Do not connect heater or mains wiring until the popper wiring, measured load current, fuse, enclosure, heatsink and safety relay wiring are verified against docs/hardware/power-stage.md and docs/hardware/robotdyn-dimmer.md.

Build

From an initialized Zephyr workspace:

west build -p always -b nucleo_f767zi -s app

To compile the RobotDyn dimmer backend:

west build -p always -b nucleo_f767zi -s app \
  -- -DEXTRA_CONF_FILE=ci/robotdyn.conf \
     -DEXTRA_DTC_OVERLAY_FILE=ci/robotdyn.overlay

Tests

west build -p always -b native_sim/native/64 -s app/tests/profile \
  -d build/profile-test
build/profile-test/zephyr/zephyr.exe

Current Hardware Assumptions

• Board: nucleo_f767zi
• Temperature sensor: MAX31865 on spi1
• Heater actuator target: RobotDyn 16A/600V AC dimmer module
• Safe default actuator: heater0 devicetree alias mapped to led0
• Fan: fixed/full-power concept only; no fan hardware control yet
• STOP input: not wired yet; safety path exists in the model

Safety Rule

The default physical command is heater off. The firmware must never make the UI, PID, profile engine or BLE transport the authority that decides whether heating is permitted.

Buy Me a Coffee

If this project helped you, you can send a few sats over Lightning:

maquinalab@walletofsatoshi.com

License

Dual-licensed under MIT or Apache-2.0, at your option.