Hi All,
I've been keeping an eye on these things the last six years or so. While the idea hasn't really taken off, neither has it gone away. The promise of no-maintenance, battery-free automatic lighting has universal appeal. That's why I went with a SON28 and a Cyo with auto-sensing feature.
With this setup, I can actually see as well as be seen. Drawbacks are the cost, weight, and need to have the dynohub built into a wheel.
The Reelight (
http://www.reelight.com/ ) is still with us, but doesn't look as bright as I might have hoped, given what I see on video:
http://www.youtube.com/watch?v=kE1lt4jN51M&feature=player_embedded#! Maybe best suited for being seen in darker environments; it appears they wash out in brighter ambient urban night-lighting. The don't appear to cast a focused beam to see with, either. Any forum members use these?
Now, there's something truly new on the market, both in concept and execution, and it looks promising...
The latest development in no-contact, battery-free lighting is the Magnic Light, whose developers are about halfway to their Kickstarter funding goal with about three weeks to go (I have no involvement with it). To read more, go to their Kickstarter development page:
http://www.kickstarter.com/projects/dynamodirk/magnic-light-get-new-energyThe Magnic is not an electro-magnetic induction generator in the same way as the Reelight because it doesn't depend on magnets attached to the spokes. Rather, it apparently works by using an extremely powerful magnet to create and amplify eddy currents generated by a passing (metallic) wheel rim. For the principles involved, see:
http://en.wikipedia.org/wiki/Eddy_currenthttp://physics.bu.edu/~duffy/py106/Electricgenerators.htmlhttp://en.wikipedia.org/wiki/Faraday%27s_law_of_induction ).
The Magnic is currently on-display this weekend at the Fahrrad trade show in Essen, Germany, so you can see it in operation there if you're nearby. The developers are Strothmann-Spiele GbR in Borgholzhausen, Germany. Project leader Dirk Strothmann is a game inventor (
http://strothmann-spiele.de/index_en.php ).
Though it looks compelling in their presentation, there are still bound to be some losses due to magnetic resistance, and there is currently a fancy carbon-fiber case for early investors, but as yet no standlight, though one is in development. It must use expensive neodymium magnets in the case; see experiments here:
http://www.kickstarter.com/projects/dynamodirk/magnic-light-get-new-energy/posts/178039In mass production, it could be the product many are looking for. It'll be interesting to see what the future brings.
Those interested in the principles of electromagnetic inductive power generation might enjoy the explanations given in the classic 1914 Hawkins Electrical Guide, which has now passed into the public domain. Volume links here:
http://en.wikipedia.org/wiki/Hawkins_Electrical_Guide , aka Danneaux's current (sorry) bedtime reading.
Best,
Dan.