This really links back to my post last year about the dynamo lighting I bought for the commuter, but I think I might have negated to mention that later, I bought an additional “always on” flasher, very popular in Holland I believe. One of these in fact:
Check their website out here
Anyway, after completing the coast to coast, Dan asked me what rear light I had bought, I couldn’t remember the name off the top of my head, and did a quick Google search, and inadvertantly discovered this article:
Hello everyone!! On this instructable you will see how to build a simple contactless dynamo for powering a bike safety light from a relay coil and some hard drive magnets.
As you will see, the electric circuit is really simple and contains only 3 bright red leds and a 4700uF capacitor. The capacitor is used just to keep one of the leds steady while you are driving. The other two leds will be blinking as the magnets pass by the coil. To have all three leds blinking you can remove the capacitor if you want. If you decide to place some more capacitors in parallel, the steady led should keep on even when you’re stopped.