ESP32 WiFi Fancontroller

The ESP32 WiFi Fancontroller is an open-source, CE-certified board designed to bring smart, temperature-driven fan control to server racks, grow tents, 3D printer enclosures, and any space that needs automated ventilation. Built around the ESP32-S2 microcontroller, it provides four independent 12V PWM fan outputs with RPM monitoring on each channel, all controllable over WiFi through Home Assistant. An integrated HDC1080 temperature and humidity sensor feeds real-time climate data into configurable control loops — including linear curve interpolation and full PID regulation — so fans ramp up and down automatically without any cloud dependency.

Expansion is straightforward thanks to a Qwiic (I2C) port for plug-and-play sensors, a standard 2.54mm I2C header, a 5V NeoPixel output for status LEDs, and GPIO breakout pads for custom wiring. Three programmable buttons on the board can trigger Home Assistant automations directly. The board ships pre-flashed with ESPHome firmware and can be reflashed over USB-C or OTA, making initial setup as simple as opening a browser and connecting to WiFi.

The hardware design — schematics, PCB layout, and firmware — is fully open source under the GPLv3 license, with all files available on GitHub. Power consumption sits at just 0.25W in normal operation and drops to 0.07W in deep sleep, keeping the board efficient even when running 24/7. An optional 3D-printed nylon case is available for clean mounting in racks or enclosures.