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
-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
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
Step 4: Drilling the Project Box
Step 5: Install the Switch, Wires, and LED
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
Step 7: (optional) Power Switch and Labelling
I used and old-style kid's labeling gun that presses the letters. It turned out pretty well.