I built this light several years ago. I bought a LEDdynamics Micropuck 350 mA LED controller to drive a Luxeon Star 1W white LED. I used a black plastic project box, might have been from Radio Shack, as the case. I sawed the case in half, heightwise, so that it would fit in my pocket. I cut a cover from a sheet of clear plexiglass (not shown in the picture).
The Micropuck is the small cube with the white label to the right of the battery clip, between the orange and green wires and the red and black wires. The red and black wires coming out of the bottom go to the battery holder and switch. The orange and green wires connect directly to the LED. Yes, I know the wires in the case are a bit too long, but hey, they’re not hurting anything. I sawed off the switch’s handle to make it more difficult to accidently turn on the light.
The Luxeon LED is fastened with 4-40 screws and nuts to a thin strip of copper. It has the lens that is not a hemisphere, it’s shaped more like a pill. This gives a widely dispersed beam, as can be seen in the picture. It made the light useful for closeup stuff like reading or working on a PC board. As would be expected, the light is hard on the AA cells, so I didn’t use it much, or else used it with rechargeable Ni-MH cells. I very seldom used a store-bought circuit to drive my LEDs; most of them were built from scratch by me.
Back to experimenting…