[rurban]

I've built 4 different fan controllers for my companies' embedded board so far.

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.

It's PWM, controlled via mraa. mraa_pwm_write()

[elevation]

> peltiers) are essential

Peltiers have a lifetime measured in cycles, cycling from active (maximum delta Temp) to inactive (both sides ambient). After 1-2k cycles, Peltiers gradually lose efficiency and transition from a heat pump to a hot plate. For this reason I've avoided them in my own permanent installations. Have you encountered this?

[rurban]

Yes, peltiers only help a bit. And don't last long. Most of the heavy work is done by huge fans.

[uticus]

> peltiers

First time I've come across this technology. A solid-state heat pump? Magic!

https://en.wikipedia.org/wiki/Thermoelectric_heat_pump