With the Magnic Light generator being nothing more than a magnet-fitted rotor inside a coil (not a clawpole arrangement), I wondered if such a thing hasn't been made before. I've been looking around for a few days and actually found such a generator inside a
Chinese-made LED shower head !
I
opened the head to access the
generator+LED assembly, took it out and
removed its turbine cage, then
stripped the turbine wheel.
Holding the little generator close to a spinning Al rim indeed does light the LED (!),
see the video !
I have to admit, my wheel must spin at 40 km/h to light up the LED nicely, but then this generator device hasn't really been optimized for use as a bike light. However it works, and it has been there before the Magnic Light. Is there anyone deep enough into patent law as to say if this is then "prior art" and anyone can use this dynamo concept ?
The LED shower head cost me EUR 11.50 (bought in Germany). Now it's not just a generator-LED thing but a SEALED generator-LED thing plus a whole shower head too. Gives an indication of the cost we can expect when China mass-produces bike lights (or phone chargers, ..) based on this principle !
Thinking of what could be possible in the future, I imagine wheel sensors for wireless bike computers where the sensor is completely battery-free and works without a spoke magnet, detecting the wheel rpm through the rim joint. Another cool product would be bike computers with permanently backlit displays, the backlight powered by energy from the wheel sensor (wired one, in this case). And wireless shifting, where the generator assists a battery in the actuator-electronics, extending battery life dramatically....
To 2_i: My wheel's eyelets are ferromagnetic, but there's no noticeable force b/w magnets and eyelets if the wheel is stationary. So the eyelets shouldn't be a big contributor. And yes, the rim joint is noticable, but this only exists once per rotation and is not so pronounced that the light flickers much. So without being very scientific there, I feel that a wheel with no eyelets and no rim joint produces more or less the same amount of power. But of course, one has to test it to be very sure.
I perfectly agree, when you say that the progress in LED efficiency is a critical contributor to the success of this dynamo concept. The LED revolution has had a lot of impact in the last few years. It also made CPF grow tremendously.