If the fans work as you describe, I could do that for 22btc and walk away with a nice profit.
All I'd do is program an arduino to output those signals, and be commanded via USB, which I could make an application for.
This all would be fairly easy, so I'd recommend doing it yourself. But if you really want to give me money I'd be happy to do it!
If you don't require actually switching the fans (ie, you have 4pin PWM fans) the difference between 50W and 1W is pretty minimal. A 64 or 100 pin uC would be plenty to run all the channels individually. If you require being able to PWM 32 channels at 4A, that's a more expensive (for hardware) project. Either way, development cost would be similar.
If all you need is to PWM fans manually with basically one setpoint (intake %, with exhaust being set a couple % lower), that would be a little simpler, especially if you're running PWN fans. That you could run with a few FETs, but you'd have less control.
Really, what you're asking for would probably require a custom PCB for 32 channels if you want to individual control. I'm an EE and I've done computer controlled fan controllers, but honestly it's completely not worth my time unless there would be a bunch of people interested in something like this. PCBs have a huge setup cost, so buying 50 units might only cost twice what buying 1 would cost. Likewise, even for a simple one $200 would be minimum wage once you actually get into how much time it would take to develop.
I'd take the 22 BTC offer. It'd be a great deal, you're really not be paying that much more than the hardware cost.
Garr255, how many channels would that be, and would they be individually controlled? It would include some kind of PCB to plug into?
Here are the specs for the fans, can an Arduino handle multiple 25khz outputs?
http://media.digikey.com/pdf/Data%20Sheets/Delta%20PDFs/PFC1212DE-F00.pdfIn addition, I am not 100% sure if that is exactly how it works, but that is what I inferred from the datasheet. It would of course need a powerful bus that could handle from 400 (8 fans) to 1600 (32 fans) watts, but at least the bus can be static and doesn't need to be power switched.
MrTeal, yeah that was my thinking, so I brought it here in hopes that an EE student might take up the challenge to provide something like it.
The idea is to start with 4 fans on the intake and 4 on the exhaust, and eventually move to as many as 16 on each side. The fans are rather expensive though