It is done, a final version of a guidance how to built up this fan/temperatue-control is available now
for the Download. (press button "Auf gehts" to start download)
Here you can find some pictures and a detailed desription in english





the main characteristics in the overview:

- by micro-controller digitally regulated fan/temperature-control,
regulation works 100% independently of the operating system (e.g. Windows...)
- with up to 8 sensors the temperatures of the PC's are supervised and
the speed of the fan's is adapted automatically
- very exact temperature sensors with a accuracy of 0,1°C
(DS1820)
- several safety functions protect against overheating the computer-hardware
- low-loss control of the fans by pulse-width-modulation
(PWM), saves energy and produces no additional heat
- the fans can be regulated into a range from 40% to 100%
- indicate the fan's "rpm" also in PWM mode,
over the whole work area
- USB-interface
- also for watercooling suitable!
- displaying of all values on LCD 1*20/2*20/4*20 (temperatures, fan's "rpm", alarm status...)
- simplest operation over only 2 keys
- very flexible configuration possible (alarm temperatures, sensor-fan config, hysteresis...)
- store of all settings in eeprom

Sorry for the bad english, i will try to improve the translation but it is a little bit hard for me. Maybe someone can help me?