DIY fan controller

[StarfishChris]

Since the fan controller I already had didn't go very low, I decided to build my own with this circuit:



This circuit is cheap since the only powerful thing you need is the topmost transistor (since I was only controlling the stock Sonata case fan I just used the same transistor - BC337-16). Resistor, zener diode & potentiometer are not going to draw much so you can get low power versions. I chose a mini pot with metal knob because it was easier, but a cermet works just as well.

So I went to Maplins, was shocked when they had everything I wanted, and set upon building this thing. I already had a box & stripboard spare, but both are around £1 each (though the size of the circuit means you can cut the stripboard in three)

After gluing wires & socket in (and cutting a few holes in the box)


Lid screwed down and connected to fan/power (maybe I should've got a bigger box after all)



This is working very well for me - since the voltage now ranges from 0v-10.2v, I can set my fan to 4v where it runs practically silently.
I may investigate using a thermistor for automatic control, but that'll be for AirAdjuster Mark II

[silvervarg]

That's a nice and simple circuit you got.
But unless you want to go below 5V for the fan you might as well buy a zalman fanmate. Cost around $5. The fanmate uses a voltage regulator, but what you have is almost the same but buildt from discrete components.
I suggest that you either secure the box very well or make some kind of insulation for the metal shaft so you can't accidentally short anything.

[StarfishChris]

The cheapest I've seen a fanmate over here is £7 - but since it only goes to 5v and the total cost is less than £3 (and much better for me since I already had stuff) I did this instead.

I agree - it would be a good idea to cover the metal parts with electrical tape. It wasn't necessary for me since I've tucked this in the corner of the drive cage now, but using a cermet and a plastic knob would be a better choice.