Adafruit EMC2101 I2C PC Fan Controller and Temperature Sensor - STEMMA QT / Qwiic

Cooling fans are essential for keeping electronics cool, but controlling fan speed can be complex. The Adafruit EMC2101 from Microchip/SMSC simplifies this with a fan controller and temperature sensor that supports 3 or 4-pin PC fans. This breakout board features programmable PWM output, tachometer input for monitoring fan speed, and both internal and external temperature sensing with 16C accuracy.

Key capabilities include:

• Control fan speed with PWM over I2C
• Monitor fan speed via tachometer input
• Internal temperature sensor plus support for external temperature sensing diode
• Configurable lookup table to automatically adjust fan speed based on temperature
• 5V tolerant pins suitable for 3.3V and 5V microcontrollers
• STEMMA QT / Qwiic connectors for easy plug-and-play I2C connectivity

This breakout board comes on a custom PCB with a voltage regulator and standard headers for breadboard prototyping. It is perfect for adding controlled cooling or ventilation to projects, reducing noise by slowing fans when full speed is unnecessary.

Libraries, wiring diagrams, and example code for Arduino, CircuitPython, and Python are available to get started quickly.