Built a cheap DIY fan controller because my motherboard never had working PWM
by bobsterlobster on 3/30/2026, 9:30:04 PM
https://www.himthe.dev/blog/msi-forgot-my-fans
Comments
by: rurban
I've built 4 different fan controllers for my companies' embedded board so far.<p>We work in very hot greenhouses, so fans (and peltiers) are essential. And proper thermal sensors. I check 4 different ones. Esp. needed is also a humidity sensor, because we don't want it to cool down below the dew point.<p>It's PWM, controlled via mraa. mraa_pwm_write()
4/2/2026, 9:24:19 AM
by: bobsterlobster
MSI shipped a genuinely good motherboard and forgot to wire one chip, so PWM doesn't work. Instead of tossing the board or living with the noise, I decided to make lemonade.<p>An Arduino Nano generates the 25kHz PWM signal, and a companion Windows application reads CPU temp and sends the duty cycle over serial. The Arduino firmware is open source (MIT).
3/30/2026, 9:30:04 PM
by: realaccfromPL
This looks really good! I am trying to do the same thing for cooling 11th gen Intel laptop motherboards with micro RP2050 board but came to the conclusion that I should just do it with ESP32 as mine has some limitations.<p>Would you mind sharing more technical review of what you created?
4/2/2026, 8:40:16 AM