I was looking for something fan-like to move some air around, specifically from under my desk at work as it gets too warm there. It’s nice in winter, but unwanted in summer.
I was looking into this which needed a 50 Euro power control module and of course a propeller. And it would create about 100W output. Cool stuff, but overkill. Of course a simple small fan for 1000 Yen would do the trick, but where is the fun in that.
In the end I found this most simple method: a normal 4 pin PWM controlled fan as computers use them. Needs 12V DC, returns 2 count/revolution and can be controlled via a simple 5V signal. Can be easily controlled by an Arduino, and it can be programmed as I like (faster/slower, depending on time, temperature). Sounds like fun and useful at the same time!
Now let’s see if I can assemble it before it gets winter…