I this (my first) instructable, I will show you how to make a solder (or any other) fume extractor. It utilizes two scavenged PC fans, which are toggled between when you flip a switch. It is powered from a wall socket with an adapter so you don't have to worry about battery life. It has a green "on" LED which is recommended.
Step 1: Materials
The stuff you need, you may already have around as some spare parts. If not, a quick stop at Radioshack and $10 should help.
-3-pin toggle switch
-LED assembly with max voltage above your adaptor's (typically 12v)
-Project Box (any size is fine but 3x2x1 is recommended)
-2 CPU fans
-~12v wall outlet power adapter, typically used in old cell phone chargers (modern chargers seem to use a lot less voltage, especially motorola)
-Optional on/off switch, added later but not pictured.
-Stiff wire. Any kind will really do, just something that can be used to hold the fans up.
Step 2: Test Your Power Supply
*Please note that we are working with a wall outlet which is extremely dangerous and sometimes fatal. Continue at your own risk and use caution. I cannot be held responsible for your injury*
We need to figure out which wire is positive and which is negative. With the adapter unplugged, perform the following step.
Cut off the entire bit that goes into the CD player or whatever it was designed for. Split the two wires. Strip one end of the wire a bit shorter than the other so we can remember which is which. CAREFULLY plug in your stripped adapter, making sure the wire ends aren't touching.. Use a multimeter to find out which end is positive. When you have them wired properly, it should read the labeled voltage. Look at all of those photos, they are ordered correctly and show it better than I can describe.
Step 3: Test Your Fans
CAREFULLY hook up the red wire on your fans to the postive on the adaptor, and the black wire to negative. If you have done the previous steps correctly your fans should give a gentle breeze. When both are working, proceed to the next step.
Step 4: Drilling the Project Box
Take off the top of the box and measure to find the center of the top for the switch hole. Mark it, and mark again about 1/2" or 3/4" down for the LED. Drill these out with the appropriate drill bits which should be written on the package. If not, use some calipers and go about 2 drill bit sizes down. Remember, you can always make a hole bigger but not smaller. Drill another hole off to the side of the box itself to allow wires to come through. Remember that you have to fit both fans' wires and the adapter's wires through these holes.
Step 5: Install the Switch, Wires, and LED
Poke the transformer wires through the hole you made in the side a moment ago, along with all the fan wires. Install the switch and LED with the nuts given.
To wire this all up, connect ALL the negative wires together (preferably with a "wire nut", labeled in two of the pictures), and wire the positive LED wire and positive adapter wire to the center prong. Install one of the positive wires from either fan into one of the other prongs of the switch, and wire the positive wire from the other fan to the remaining switch prong.
Step 6: Supports
If these fans are going to be right above or next to what you're working on, they may need some supports. Try sticking 2 - 4" long pieces of stiff wire through some of the holes on the big fan, and pushing a 2' strand of stiff wire through the small fan, wrapping the wire around that, and sticking the other end of the stiff wire through one of the top open holes of the big fan.
Step 7: (optional) Power Switch and Labelling
Close it all up, test it out. If made correctly, the LED should come on when plugged in and the switch should toggle inbetween the two fans. When everything works right, you can label the power light, which side of the switch turns on which fan, and give it a name (i.e. "Fume Extractor")
I used and old-style kid's labeling gun that presses the letters. It turned out pretty well.