I got tired of the fan noise from my computers and couldn’t find a solution that worked the way I wanted it too, and I had nothing better to do at the time 🙂
As you probably realize the solution to this problem is to add more fans but regulating them at a lower speed to get the same air flow and thus much less noise. I designed a small PCB based on an Atmel AVR AtMega16 and a USB interface with a FTDI chip. The fan controller works stand-alone and doesn’t need a software running on the computer. The USB port is used for connecting to the controller, with a software I developed, to set up the behaviour of the controller. It can run up to 6 fans and has 6 temperature sensor inputs.