Temperature controlled xbox 360 fans.

[algar32]

My xk3y has taken away the need for a noisy disc drive, but my rear fans are still very loud.
I want to remove my xbox 360 fans and replace them with quieter fans like this: http://www.youtube.com/watch?v=W90oIQTu5wI

But I would also like to have them be temperature controlled via micro controller in a similar fashion to this: http://alan-parekh.com/projects/pwm-fan-controller/
(with temperature control the xbox will be quieter at dash/netflix and louder during games rather than just loud all the time)

I have a few questions:
1. If I follow the procedure of the second link will I be able to program a pic chip with my avr dragon (all I have right now)?
2. The programming should be relatively simple correct?
3. Will I be able to power the fan controller from somewhere on board or will I have to run a light to power outside of the xbox?
4. Do you see any major problems with the general idea of this project?



Any advice is appreciated. Thanks.

[UAirLtd]

1. Yes apparently you can do that, but perhaps also consider using an AVR instead of a PIC?
2. The code is really straightforward: read ADC to get temperature, multiply by some scaling factor, ensure value isn't outside desired range (a minimum fan speed for example), output PWM (which could just be a variable loop)
3. You should be able to power the controller from the existing fan power supply, assuming that fan supply is a fixed voltage (probably 12V, in which case you'd need a voltage regulator to supply the necessary voltage to the controller). There are also alternative internal power points all over the place you can solder to, but the existing fan supply wire is the easiest and cleanest (reversible) option, assuming it's a fixed voltage.
4. No major problems, sounds like a straightforward project if you've already got experience with microcontrollers.

[algar32]

Thanks. I was hoping I could just edit the guys code on the pic (unless someone else has done something similar on an AVR already). If I use a non pic chip will the rest of the circuit remain the same? I haven't done any real work with micro controllers. I am a sophomore ECE and have taken a C++ course and followed a few tutorials using avr bug (just blinking leds and basic servo/dc motor control). I am worried if I go with something other than the pic I might have some trouble getting the program set up. As simplistic as it is, I havn't done much in C++ and have done little to none with micro controllers so I don't want to end up with a project I can't finish in a timely fashion. If I am to proceed with this I will definitely be running the controller through the existing fan supply as you suggested.

tldr; I don't have much experience with micro controllers, but the seems like a fairly simple project to get started with if the circuit remains the same and I am able to program it.

Thanks again for your help.

[UAirLtd]

Circuit's the same. I haven't looked at the code, but judging by the function of the circuit, if you asked 10 programmers to write the code for 10 different microcontrollers, they'd all look remarkably similar.

So it's up to you: copy/paste it as a PIC project, or try to port the code to AVR (which is either trivial, or mildly frustrating, depending on your experience level). I would say you should pick the option based on whether you intend to be using PICs or AVR in the future.

Personally, I would try to go set up your coding environment (I guess MPLab), and configure the AVR dragon to program PIC chip, and if you succeed, go with the PIC. If it turns out to be a difficult task to do, or you encounter compatibility issues between MPLab (or whatever IDE/compiler it is you'll be using), the AVR dragon, and the PIC chip, then go with the AVR. I can imagine that dealing with non-compatible compilers, drivers, programming dongles, and micrcontrollers would be a much larger headache than writing code for either of them.

[algar32]

Thanks so much for your help. I will post back here if I proceed with the project before school starts back up.