EMC2101 Fan Controller & Temperature Sensor
I2C fan controller with dual temperature sensors. Reads internal and external temperatures and controls a 4-pin PWM fan via duty cycle or target RPM.
Say it to PAL
“Turn the fan up when it gets warm.”
The code PAL writes
p.onSensorChange('qwiic-emc2101', 'internal_temp', async (temp) => {
const duty = Math.min(100, Math.max(0, (temp - 25) * 4));
await p.write('qwiic-emc2101', 'set_duty', { duty });
p.log(`Temp: ${temp}°C, Fan: ${duty}%`);
});
await p.waitUntilStopped();“Keep an eye on how fast the fan spins.”
The code PAL writes
const rpm = await p.read('qwiic-emc2101', 'fan_speed');
if (rpm === 0) p.notify('Fan stopped or disconnected!');
else p.log(`Fan running at ${rpm} RPM`);When to pick it
Choose when the project involves active cooling — enclosures, 3D printers, server cooling, or any PWM fan. Also works as a simple dual-channel temperature sensor.
Good to know
- External temp reads -64°C if no external diode is connected — this is normal, not an error.
- RPM measurement requires a fan with a tachometer wire (4-pin fans). 2/3-pin fans can be controlled but RPM cannot be read.
About it
The EMC2101 is a fan controller and temperature monitor in one. It has an internal temperature sensor and an input for an external temperature diode (or thermistor). The fan output supports 4-pin PWM fans with tachometer feedback, providing closed-loop RPM control. Automatic fan speed control via programmable lookup table allows hands-free thermal management. Ideal for cooling electronic enclosures, 3D printer hotends, server fans, and any project needing temperature-based fan control.
Where to buy
Facts
Tested
It is in our catalog, but nobody has checked it on a real board. It may not work yet. Its driver is written, but it has not been tested on hardware yet.
I2C address
The EMC2101 Fan Controller & Temperature Sensor answers at I2C address 0x4C. The address is fixed.
Current
1 mA
The catalog lists a typical draw of 1 mA for the EMC2101, copied from the maker’s description and not measured by Palpable.
Board size
25.4 × 17.78 mm
The EMC2101 board measures 25.4 × 17.78 mm and stands 4.6 mm tall with its parts. It has 4 mounting holes. These dimensions are from the maker’s mechanical drawing.
Free to reuse
Every fact here is open data under CC BY 4.0. Copy it into your own docs or code, and credit Palpable. Download it
This record was last changed on October 25, 2026.