MicroFAN (Part 2)

Part 1, 2, 3

Let’s talk about some basic electronics. MicroFAN is really easy and requires few affordable electronic components: a 12V fan, Arduino (Uno, Nano, etc.), a 8×2 LCD (a 16×2 LCD will do the job too), a rotary encoder, typically a 30 pulse 15 detents per round (so as to say 1 cycle per detent) will be great, a N-Channel MOSFET: an IRF540 or equivalent will definitely be overrated but it’s OK because you  obviously have one in your scrap box and it will allow you to drive a  dozen of fans like a charm. Plus some extra components.



Connecting the LCD is almost trivial. You may skip the potentiometer and wire VEE to ground. Wiring the rotary encoder is trivial. The fan driver consists in a hot spot (Vin, or +12V in our case) connected to the positive pole of the fan. The negative pole is switched (or not) by the MOSFET transistor. Although the 1K resistor in serial with the transistor gate is not mandatory, it may prevent cries in case of wiring errors. The power may come from any wall plug adapter feeding MicroFAN with a stable +12V under a few hundred milliamps (250 or more will be just fine for driving one fan).

For your records, here is the pin-out for the TMP04 temperature sensor:


What else ?

The best is probably to use an Arduino proto-shield to hard-wire components. I use this principle a lot so that I can swap arduino boards from one application to an other without having to rewire the required components. I suggest that you choose the bare board which is cheap compared to the assembled one (x4 more expensive):


and a 36 male pins header (2.54 mm) like this:


that you can get for less than 1€ each in quantities.

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