This generated documentation covers the ESP32 firmware interfaces for staged water-only aquarium cooling control, fan PWM output, fan RPM monitoring, OneWire temperature sampling, MQTT telemetry, serial diagnostics, OTA update support, and fault policy decisions.

Use the project README for setup, wiring, build, and operating instructions. This Doxygen site focuses on source-level API documentation.

Firmware Areas

Control engine: water-only staged cooling, runtime validation, and PWM command calculation.
Fan curve: measured PWM-to-RPM mapping and plausibility helpers.
Fan driver: ESP32 LEDC PWM output with low-speed start boost.
RPM monitor: interrupt-driven tachometer pulse counting.
Fault monitor and policy: fan plausibility, alarm state, severity, and response.
Sensor manager: OneWire discovery and DS18B20 water-temperature sampling.
MQTT telemetry: network status, controller-state publishing, and validated remote configuration for control parameters.
Controller sketch: Arduino setup/loop orchestration, serial diagnostics, target persistence, OTA upload plumbing, and module wiring.

Circuit Summary

ESP32 board running the Arduino core.
DS18B20 water sensor on the shared OneWire bus.
Four-wire PWM fan with separate PWM command and tachometer feedback.
MQTT telemetry is optional; local cooling continues without Wi-Fi or broker access.
MQTT can update target temperature, hysteresis deltas, and fixed low/high PWM stages, with persisted validation on the controller.

Arduino Runtime

The firmware follows the standard Arduino lifecycle:

setup() configures serial diagnostics, preferences, sensors, fan PWM, RPM sampling, and telemetry.
loop() remains non-blocking and repeatedly advances sensor sampling, control calculation, PWM output, RPM measurement, fault evaluation, diagnostics, and telemetry publishing.

Documentation Policy

This site is generated with WARN_AS_ERROR = YES, so Doxygen warnings fail the GitHub Pages build. New firmware modules should include @file documentation, explicit API comments, and Arduino-specific notes for pins, timing, units, and runtime assumptions.

Generated Output

The GitHub Pages workflow builds this site from Doxyfile and publishes the HTML output from docs/doxygen/html.