a friend of mine builds his own ultralights and airplanes, and gave me a bit of a project to work on. he wants highpower led lighting for the exterior of his newest plane. i'm not nearly an expert but i have done some projects,mostly Rc cars and moddong my x-box, so i have a grasp of the fundamentals. so far ive been doing reasearch and putting a parts list together. the one area im caught on though is the 555. ive read all the tutorials and faqs i can find but im still not sure i have it. the strobe array is powered via a 12v system very much like a car. three CREE High Brightness LED Lamps (Forward Current:500mA, Forward Voltage:3.5V) with 3.3 ohm 1 watt resistor, powered via 500 ma buckpuck (http://www.leddynamics.com/LuxDrive/datasheets/3021-BuckPuck.pdf) what ive been trying to do is strobe the leds by attatching a 555 circuit via the control on the buck puck. now for the 555 i was thinking of using FAIRCHILD SEMICONDUCTOR - LM555CN (http://www.fairchildsemi.com/ds/LM/LM555.pdf). what i need to accomplish is on off time of 600 to 900 milliseconds and an on time of about 10 milliseconds (or as long as is needed for a vissable strobe.) i was thinking its gonna be an astable with R1 2000 (K Ohms) R2 20(K Ohms) C .47(Microfarads). i also need the compunants to be as small as humanly possible. if you guys can tell me how far off i am and offer any help it would be much appreciated.