Starting to learn electronics, first project

Hey,

I was thinking about ways to make something useful and learn at the same time, and I had an idea; a temperature based fan controller for PC. My idea is that the device would read temperatures from the different parts of the PC, and according to those temperatures adjust the fan speed by adjusting the resistance.
There would be about 4 or 6 slots for the fan connectors, and 6 slots for temperature sensors that would be associated with the fans. It would draw power from PC power supply's molex connector.

The easier way to make a fan controller would probably be using manual potentiometers to adjust the resistance, but I figured it would be much more interesting if it was actually automatically adjusted based on the temperature.

The thing is, I know very little about how to actually begin making this thing, and before going blindly into the jungle to learn, I figured I'd ask advice from people who know better than me.

Where should I start? Any general design tips? I presume I need micro-controllers?

First you need to decide which temperature sensors you are going to use. LM35 is a common one. Then there are others like DS18X20 and many more.

You can design this without using microcontroller but it would be simpler if you used a microcontroller. However that would mean you'd need to learn that and it is up to you to decide if you want to.

You shouldn't look to adjust fan speed by adjusting resistance. Study up on a method called pulse width modulation (PWM).

That should be quite a lot to start you up. Read up more on the topics I mentioned and then you can proceed further.

Hope this helps.
Tahmid.