I changed the cooling fan in my computer psu, but the problem now is that when the psu is cold, it spins so slow that the alarm triggers in the psu, and starts beeping... It is doing so for the first 15 minutes, until it heats up enough to spin the fan a bit faster.
My goal is to use an arduino to fake the rpm signal, so it reads how many rpm's the fan spins at, and if it is too low, it then just makes a whole lot more, to prevent the psu from beeping.
I got everything down how I want to fake the signal and so, but I am unsure of how to actually connect it all together.
After looking at how the pins on the fan behaves, it seems to pull the rpm pin down twice per revolution (same as the one I got in my network cabinet), but how do I actually connect the arduino to it?
Can I just use a TIP102, and connect it to minus, the rpm wire, and then the arduino? (with common minus of curse) Or should I take something else than the TIP102?