Adafruit has announced the availability of a new temperature sensor and fan controller they have created in the form of the EMC2101 I2C. Priced at just $5.50 the fan controller and temperature sensor area capable of providing both internal and external temperature sensing, with a 1°C accuracy, and are a perfect companion for any 3 or 4-pin PC fan you may find.
“The EMC2101 from Microchip/SMSC is a fan controller with temperature monitoring, and it will take care of all of that for you with a programmable PWM output and tachometer input.
Four pin PC fans have a power and ground pin (those are red and black) and then two more pins. One of those extra pins, the PWM pin, allows you to set the speed of the fan. The last TACH pin is for a tachometer output that allows the EMC2101 to monitor the speed of the fan to make sure it’s working as expected. Instead of using a PWM output and counter input on your microcontroller, this chip will take care of that all for you, all over every-day I2C.”
“In addition to allowing you to control a fan, the EMC2101 includes an internal temperature sensor, as well as connections for an external temperature sensing diode. If you use an external temperature sensor, you can even configure a lookup table (LUT) that allows you to set different fan speeds depending on the temperature, and the EMC2101 will automatically adjust the speed depending on the temperature.”
Source : Adafruit