This is a little bug-zapper that works with a computer FAN and a CCFL inverter.
The insects will get sucked-in and then get zapped by a 2kV arc :D
It's powered by a 9V battery and is easy to use. The compact design also makes it mobile.
A video of the zapper in action:
Step 1: Requirements
• a sheet of cardboard (or PVC pipe, better)
• cutter knife
• hot glue
• computer FAN
• CCFL inverter (paper scanner or screen back-light)
• a 9V battery
• a 9V battery holder (clip)
• some wires
• a push-button
• some bare wire
• electrical tape
• high voltage diode (3kV+) or three times 1N4006 or 1N4007
• high voltage capacitor (500v +) (somewhere between 60nF and 10nF, NOT HIGHER!)
(using a bigger capacitor won't harm the circuit, but it would become lethal).