I have always wanted to experiment with Light Emitting Diodes (LEDs) and long exposures. Unlike incandescent bulbs - the sort that light your hallway - LEDs use very little power and give off next to no heat. They are hardy too. The actual light source is encapsulated within a solid plastic casing. With the appropriate measures in place, you can whack them, stamp on them, and drown them. And since they are so tiny, you can mount dozens of them onto regular cardboard to create interesting effects.
The only slightly tricky bit is wiring them up.
Here is something I cobbled together a few days back. It is a single, blue LED on the end of a 4m long cable. The cable is black so that it won't show up in the photo. It is also long enough to be swung around and generally mishandled. On the other end is a simple electronics circuit.
Batteries are best for this sort of thing because they are cheap, light, portable and cannot electrocute you. The alternative would be a cumbersome power supply unit connected to the mains. The small microchip next to it is a 555 timer. By the mere flick of a switch, the LED will begin to flash on and off. The two knobs on the right control the timing.
Anyway, enough of the science. Here are some of the results. Obviously I am not trying to capture award-winning photos just yet - this is just a test.
By the way, check out this Light Graffiti.
(All photos taken with a Canon 5D + 24-70mm f/2.8 L USM lens.)