Computer Fan RPM tach

Thread Starter


Joined May 29, 2005
Anybody know how to make a tachometer for a computer fan that doesn't have the built-in tach? I want to be able to make a circuit that can read the fan's RPM and send it to the motherboard so I can read it in the BIOS and motherboard software. I was thinking of using an infrared system but don't know how to design it. Can anybody help or have suggestions?