I built this in May, 2003 using an expensive plastic project case. It worked very well, and put out a .lot of light thanks to the high performance transistors. I added the yellow LED to make the light a little warmer, since white LEDs tend to have a lot of blue light. The URL I gave is still a good one. His schematic shows a BAT48 Schottky diode and capacitor on the output. I didn’t use these, the LEDs are directly connected to the collector of T2.
This photo was taken before I glued the components down to make it rugged enough to withstand rough handling.