The Adafruit EMC2101 breakout is an I2C fan controller and temperature sensor that makes it easy to integrate 3-pin or 4-pin PC fans into your projects. The Microchip/SMSC EMC2101 handles PWM speed control and tachometer monitoring over I2C, so you don't need to dedicate PWM outputs or counter inputs on your microcontroller.

In addition to fan control, the EMC2101 includes an internal temperature sensor and support for an external temperature-sensing diode. With the external sensor connected, you can configure a look-up table (LUT) that automatically adjusts fan speed based on temperature — fully autonomous thermal management without any code running on your microcontroller.

Key Features

• PWM Fan Control – Programmable PWM output for 3-pin and 4-pin PC fans
• Tachometer Input – Monitor fan RPM to verify the fan is running as expected
• Internal Temperature Sensor – Built-in temperature monitoring with ±1°C accuracy
• External Temperature Input – Connect an external sensing diode for remote temperature measurement
• Automatic Fan Speed LUT – Configure temperature-to-speed mappings for autonomous thermal management
• I2C Interface – Simple two-wire communication for control and monitoring
• STEMMA QT / Qwiic – Dual I2C connectors for solderless daisy-chaining
• 3.3V and 5V Compatible – On-board voltage regulator and 5V-tolerant pins

Ideal For

• Adding cooling fans to electronics enclosures
• Automated thermal management for 3D printers, servers, or custom builds
• Quieting noisy equipment by reducing fan speed when cooling demand is low
• Environmental monitoring with temperature-triggered ventilation

Package Contents

• 1× Adafruit EMC2101 I2C PC Fan Controller and Temperature Sensor – STEMMA QT