This is straight forward, this deals with the turn signals on the back of the bike. I have a circuit using a standard 555 Timer, with the switch being a on the bicycle handle bars. I designed the circuit to turn the light on for .5s, off for .5s, and so on until it's off. For the LEDs, after some research in digikey's automotive section, I found high power LEDs used in exteriror signals and brake lights rated at .5W per LED. It may sound like a lot, but remember these lights are only on for a few seconds at a time when you are making a turn.