Cree X-lamp MK-R LED, making the brightest bike light in the world... help!

I just ordered/received in the mail a Cree X-lamp MK-R LED. My needs are these: I want a flashing function at a lower wattage (2 or 3 W) for city bicycling, and a solid beam option that's crankable up to the full 15 W (which Cree claims will put out 1769 lumens) for nighttime off-roading. How can I build this? I'm happy to take apart other flashlights, blinky lights, boomboxes, and old computers if necessary. Some things I've read have lead me to believe I'll have to attach a heat sink to the LED.

I know basic things about circuits, but I've never built a complex or high powered flashlight. How should I make this thing?

Cree offers these specs for the LED:
max drive current: 1.25 A
max power: 15 W
light output: up to 1769 lm @ 15 W, 85 degrees C
typical forward voltage: 11.7 V
thermal resistance: 1.7 degrees C /W
reflow solderable

Heat management is your best friend here. I'd recommend an external power supply so you'd have more room to build and manage heat when running this hot.

Tiresius said:

Heat management is your best friend here. I'd recommend an external power supply so you'd have more room to build and manage heat when running this hot.

Click to expand...

Ok. I think I'm going to try to build an astable circuit with a 555 timer-- or maybe several, so I can have reasonable flash frequencies at different wattages. How should I go about this? And for heat management, will it be good enough to just thermal tape a heat sink to the back of the LED? (where does one get thermal tape?)

Remember that the Vf of this emitter is relatively high. Expect that the heat will build up even if you're only running it at 1.25a. I never trusted thermal tape before and will not trust it now. I'd use the least amount of thermal paste or epoxy possible and have the heatsink milled to exact dimensions for the mpcb board. If not, I'll just thermal epoxy it onto the flat surface of the heatsink.