⚡ ESP32 4-channel PWM fan controller for server racks

CoolMaker Lab has released an open-source, Home Assistant-compatible ESP32 4-channel PWM fan controller designed for server racks and NAS systems. The board independently manages up to four 4-pin PWM fans, offering precise speed adjustment and RPM monitoring for DIY enclosures and network cabinets.

The controller utilizes an ESP32-WROOM-32-N4 module with 4MB flash, 2.4GHz Wi-Fi, and Bluetooth LE capabilities. It supports 1–100% PWM speed adjustment via four independent connectors and includes tachometer inputs for real-time RPM tracking. Individual fan power switching is handled by TPS22810DBVR-based load switches, enabling complete shutdown for zero-RPM operation.

Temperature-based automation is supported through four external DS18B20 sensors, allowing automatic fan speed adjustments. The device features a web interface, an HTTP REST API, and Bluetooth proxy functionality for seamless integration. The latest v2.0 hardware and firmware also introduce optional support for the LD2402G 24GHz mmWave radar, enabling presence-based automation scenarios.