With Halloween coming up the eager among us are starting to pick out costumes. As The Joker was last year's most common costume I suspect this year will be Iron Man, so let's run with it. To create a semi functional pulse weapon

You'll need the following:

• An old disposable camera.
• A bottle cap, CD case and arm strap
• Two push buttons some wire and an AA battery holder
• An enclosure for your project, a soldering iron and some glue

First a word of safety, Xenon bulbs need a fairly high voltage to operate, in our case around 300 volts and an even higher voltage to trigger, 4000 volts in our case (for reference the plugs in your house are 220 volts). As dangerous as this sounds a camera circuit can only provide a little power at a time so they are pretty safe but getting zapped by one of these guys stings like hell and will figuratively give you a heart attack. In short, always remove the batteries and trigger the flash before working on the unit.

Let's get started then. First, open your camera and remove all the electronics, taking note of what buttons were connected where. Most disposable cameras have two, a charge button and a trigger button. The charge button will most likely be connected to the circuit board directly, while the trigger button is usually connected to two metallic plates. Solder in your push buttons to these locations so you can use both functions as usual.

Next remove the Xenon bulb and metallic casing from the circuit board. Note the big round component on the circuit, this is our storage capacitor - connect a wire to each leg of this component and connect one to each end of the Xenon bulb. Finally wrap some un-insulated wire around the bulb and connect this to the connection on the circuit board where the metallic shield around the bulb was attached. Make sure that none of the above mentioned wires touch. You can attach the battery holder and place this unit inside the enclosure with the bulb hanging out on one end.

Sand down your bottle cap and cut a big hole in the top, glue in a small disc cut from your CD case and sand it down so it's not transparent. Insert the bulb into the cap and glue it in, the more glue you use the safer it is, so fill up the cap if you can. At this point no contacts should be even remotely exposed, if there are any put a generous amount of glue around them for isolation.

Finally attach the arm strap to the bottle cap and another around the enclosure, put the bulb on your palm and the enclosure around your wrist and you're ready to go. Simply press the charge button and let it charge up for a couple of seconds and then press the flash button to have it release a blinding flash of light from your palm. [MS]