Hello! My chimney in the basement had once a ventilator, but it fell out after 15 years of use (yeah…) and the ugly hole is there, so I decided to make a new one. It’s nothing fancy and it works. Cost me nothing, like usual, might not be as strong as those industrial fans but hey – it’s homemade :D
Ok, so all you will need is stuff you can find around the house (hopefully :D)
1. Computer fan (will be slightly modified)
2. Paper tube
3. 2 LED’s (I used one red and one green for 2 mode indicators)
4. ON/OFF switch
5. Piece of cardboard
6. Phone charger as power supply
7. Hot glue
8. Soldering iron
9. Some wires
If you have all of this, we can begin.
We can start from modifying the fan a little. I’ll be using a medium-size one
In the photo you can’t see the third wire – it’s because I modified the fan before taking a picture. But a fan usually has a third wire. I only left minus and plus.
This mod will remove fan’s speed limiter and make it spin as fast as you want. Speed depends on the voltage you give. 24v makes the fan fly :D
Open it up and see the three connections. Determine which one is for plus and which one is for minus, then remove the unused one (use soldering iron to remove it completely).
Don’t ask me how does it work, because the wire doesn’t seem to do anything anyway, but the fan started to spin faster and faster with more current when that wire was removed…
You can now safely apply hot glue and put the fan back together. I didn’t put anything back as a fixate for the fan itself, so I can remove it easily whenever it needs cleaning.
Ok cool. Now that we have that sorted out, lets mod the tube that we have. I have used a paper tube that things like tape gets rolled on. Mine was heavy-duty :D
Take the fan and mark the lines where to cut the gaps. Of course you can just glue the fan to your tube and that’s it, but I wanted to make mine so that I can disassemble whenever I have to.
Cool. Time to put everything together. For this you will need the rest of needed parts – LED’s, a switch, wires and a phone charger.
First the a piece of cardboard you have and mark where you would like to cut the hole. I’ve cut in the middle and put the tube in, apply glue.
Determine where you want to have your switch and 2 LED’s. Make some holes and glue them in.
You probably know that connecting LED’s directly to the power source is dumb – they will burn out instantly. So for this I used 2 390ohm resistors. To be precise you would need 150ohm resistor for a red LED and 180ohm for a green LED – assuming, of course, that the source current is 5v, but 380 is what I had closest to those ranges so I used them, still works nice.
Like I said before – more current is better, but 24v would probably be too much. The fan doesn’t seem to heat a lot, but still… I’d say 12 would be enough.
Time to put put the final part in before making it work. Take your charger, cut one end where the connector is and strip that wire. I was lucky to use an old “Sony Ericsson” charger which gives only 5v, but it’s kinda enough.
To connect everything, you will have to use your own knowledge. I was able to have it working from first time because I knew how to do it, but I can’t draw you a schematic and I forgot to take a pic of the back how I did it, but I don’t think it would be any help anyway :D
Concept is really simple though. Connect the fan and the source with the switch normally in a ring. Then connect red LED as a plugged-in indicator directly to the source. After that connect the green LED to a switch and to the source, so that when a switch is turned on, the fan starts to spin and an LED is lit up.
Doing this keep in mind that the fan will only spin into one direction, so do not mix plus and minus as it won’t spin at all.
Also keep in mind that LED’s can pass through current only to one direction – from negative to positive, so if you mix the poles – it won’t work at all.
And a working set looks like this