For a pet project of mine, I like to generate power from a rotational motion. (similar to bicycle tire turn). I want to build the system without a battery where as the tire turns I generate enough electricity to turn an LED. It is ok if the LED is dim in slower speeds, my application will only cover the high speed cases.
What is the best approach to this?
I do not want a magnetic coupled system, this should be one piece.
update
The device is for bicycle, it is an active reflector. I wanted to use the rotation of the bicycle and light an led from the generated energy. T I didn't want a two point solution where I put a magnet somewhere and use that to generate energy. Just use the rotational motion. Some piezo material that would accumulate energy and use to pulse a led for a few msec every second.
Best Answer
I don't understand the "one piece" requirement, but what you need is a motor.
Electric motors have the great power of being capable of converting mechanical (rotational) energy in electricity and vice versa, and with a quite high efficiency.
But if you need to take the energy from a "linear" movement, like from the surface of a tire, you need a gear which takes the rotation from the movement of the tire, like a dinamo. But consider that the energy that you are generating (plus some losses) is taken from the wheel, so you are making an opposing force in your system.
Consider that this kind of harvesting is not the LED's best friend, as it gives a variable voltage and current, and the LED wants them to be quite regular, especially for the limiting circuit specification. That's probably one of the reasons because of many bycicle lights with dinamo use incandescent bulbs.