All of you must have seen the vast number of available Fan Controllers available. Take Vantec Cooling for example, they have many controller panels, not only for managing fans but for other purposes as well.

So, the question is, why would one want to build a fan controller if it can be bought? There are many answers to that, but the 1 main thing is that it is unique. No other person has that installed if you DIY. This is (i think) what drives modders to mod.

So, back to the Fan Controller. The main goal was to build a 4x2 (4 busses x 2 fans per bus) fan controller. As the idea took shape, i realised that i had lots of more free space to add more stuff. So, i added a VU meter and a Hard Disk reading indicator just for the bling of it.

Now, lets go back to the steps on how i made it. Mind you, the Fan Controller circuit is not mine. I just got it from the net years ago and made slight changes to it. The PCB design is my own though. The VU meter circuit is very easy to design, based on the datasheet.

These are the stuff you are going to need to make the Fan Controller:

4 x 2.2k potentiometer
5 x 5mm LEDs (1 for power indicator and the other 4 for each bus power indicator)
4 x LM317T Variable Voltage Regulator
5 x 180 ohm resistors
4 x 240 ohm resistors
8 x 3 pin connector(to connect the fans)
1 x 4-pin molex connector (male)

Sorry but i lost the circuit diagram, but it is easy to make out from the PCB design.

PCB Design (Component Placement)

PCB Design (Layout)

PCB Design (Layout + Component Placement)
After you have completed this, please remember to Heat Sink ALL the LM317Ts. If not they WILL overheat and shut down.

Eagle File: PCB

Now for the VU Meter

You will need:

1 x LM3915 Dot/Bar Display Driver. NOTE: LM3914 can be used too, but LM3914 is linear,
whereas the 3915 is dB, 3dB/step, making a better looking outcome.
10 x LED (any colour)
1 x 2.2k resistor
2 x 10k resistor
2 x 1uf electrolyte capacitor
2 x IN4148 fast switching diodes
2 x 2pin connectors (1 for power, another for input)

Schematic

PCB design (Component Placement)

PCB design (Layout)

PCB Design (Component Placement + Layout)
EAGLE Schematic and PCB Design: Schematic, PCB

Putting it all together:

This part is not described in detail because it is up to the users imagination. I will just show you a pictorial guide of how I managed to do it.

Breadboard testing is done 1st to ensure everything is working before starting on PCB construction:
Both boards done, and fan controller fixed to perspex( note that i have used fibre optic cable to route the light from the leds to the panel, that way you get a neat 1mm display of each led, and not the bulky 5mm leds):






Now fixing all the parts to a unused cdrom player casing (note that i added a DIY kit running leds for the hard disk led):




Done at last! Now, the video of the breadboard testing and the testing of the final product: It works like a charm!

Breadboard Testing: