Turn volume down before starting video - ugly noise :)
Things you will need:
- A (broken) computer power supply that has a big (working) fan.
- 12V DC power adapter (I use my "lab bench power supply", made of another PSU - old but working one)
- A filter - if you have charcoal filter, great; I will show how I improvised a filter from cotton cloth, but I don't have any idea if this does extract anything or not.
- Some kind of soft net - like the bags in which mandarins or other fruits are sold
- Thin cardboard - cereral box for example
- Tools: screwdriver, scissors, soldering iron
Step 1: Dissassemble the PSU
The PSU I used had a fan that drew air into the PSU casing so exactly right. It also had enouch holes (in my opinion) on one side.
- Keep the PSUs switch and cut its wires as far from it as possible. Also keep the fan wire intact.
- Desolder the other side of fan wire connector off from the PCB.
Step 2: Make Electrical Connections
- Solder the positive pin of the connector to one of the swich wires. Solder the ground from the power source to other connector pin. Solder the positive from power source to the swich. Isolate the connections.
* Using the connector from PCB makes it easier to mess with the filter assembly and changing the filter in the future, as otherwise the halves of casing would be quite uncomfortably closely attached to each other.
Step 3: Make Filter Holder
Step 4: Optional: Make a "filter" From Cotton Cloth
So, to make the "filter" you need some fireplace with fire.
Find a 100% cotton cloth and some aluminium foil. Cut piece of cloth that is a bit bigger than the fan and wrap the foil around it.
Place it in fire (on glowing coal). The package can swell and some flames can come out from the folds. I kept it in fireplace for 2-3 minutes until the flames stopped and nothing seemed to change any more. Take it out, but be warned - it does not smell good in the beginning, better take it outside, open the package and let it stay outside for a while. Mine was a bit fragile, but stayed together enough for the purpose. If it comes out too fragile then I suggest try again with less time in the heat.
Step 5: Assemble the Filter Into Holder
- To keep the filter in place cover it with net and put the cardboard thing around the fan so that it holds the edges of the net.
* I also tried to put there a layer from paper napkin to catch some solid particles but then it seemed the air was bouncing back from the filter too much and I removed it, I didn't really do a smoke test for that setup to be honest... Try and see what your fan does if there is one more layer in the filter.
Step 6: Final Touch
Connect the wires and test if the fan still works. Then close the casing and ... to the soldering, this time bit healthier way.