Well, if you can call it that! It's so much more, though:





This is a custom tail light I built for my trike. It is made of 120 super-bright red LEDs, and two 1W Luxeon LEDs. The two Luxeons are in the middle, they shine hotter than the rest of the bar. The 120 red LEDs are separated into two groups of 60, which alternately flash (you just can't tell from the picture). The flash rate is about 2.5Hz.





As you can see, the lights brightly illuminate the road, walls and everything behind the trike for at least 25 feet. The lights are visible from much further away than that, though. They are also easily visible in daylight.



The case is a 19" long piece of PVC conduit, 1" inside diameter. The PVC was later painted black with Krylon paint. Inside of the PVC tube is a clear acrylic tube, 1" ouside diameter, 0.875" inside diameter. The LED light bars are sealed inside the acrylic tube. The flasher circuit for the LED light bars is also contained in the tube. The ends are closed off with some metal caps I found at an electronics store.



The control box is mounted on the boom of the trike. It contains two Luxeon drivers, a 1000mA BuckPuck for the two 3W white LEDs on the front, and a 350mA BuckToot for the two 1W rear red LEDs. There is a single power switch, and a potentiometer that I can use to vary the brightness of the headlights. One wire goes to the headlights, one to the tail light, and one to the battery. I used a 11.1V, 7200mA Lithium Ion battery from batteryspace.com to power the whole thing.

So how well does it work in traffic? Well, cars actually give me more space. As I hypothesized, the extreme width of the tail light causes cars to pass with a wider margin than ever before. The light is easily visible from hundreds of feet away, even during daylight. The flash rate is roughly equivalent to that of a train crossing light or school bus, so it's something drivers are used to slowing or stopping for.

The total cost? Ummm, expensive. The biggest expense was the battery, actually. Darned import fees. I'll be posting more detailed pictures and instructions on my website soon...