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Freelight dynamo system.

Discussion in 'Lighting' started by Clive Mitchell, Dec 8, 2004.

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  1. I like this design.

    http://www.freelights.co.uk/

    I don't know if it's been mentioned here before, but it's a simple
    design for a flashing rear (and front) light on a bicycle where the
    rotation of the wheel causes magnets to pass in the vicinity of a small
    film canister. The canister contains a loose magnet and has a coil
    wound round the outside. As the magnets pass, they make the internal
    magnet flip over and generate a sharp current pulse in the coil which
    makes the LEDs flash.

    The advantages? Low friction losses compared to a conventional dynamo,
    and utter simplicity.

    It's a neat idea.
     
  2. Yes, a very neat idea with a number of interesting advantages.

    However, the explanation on the Web page claims "No Friction" and "No
    Resistance", which, of course cannot be true. The old "get energy out
    for no energy in" argument. How wonderful if we could achieve that. If
    you read the fine print the author does explain that the system does
    create some small amount of drag, enough to power the lamps, as
    required by the laws of physics, and states the claim of "No Friction,
    No Resistance" really means the "extra" friction and resistance of a
    conventional dynamo." Better to have stated this up front.

    --
    Vic Roberts
    http://www.RobertsResearchInc.com
    To reply via e-mail:
    replace xxx with vdr in the Reply to: address
    or use e-mail address listed at the Web site.
     
  3. sfb

    sfb Guest

    When it is me vs. drivers, give me batteries every time. I demand a
    dependable flashing light that drivers can see all the time every time.

    At 30 MPH, a car covers 500 feet in 11 seconds. The light has to flash
    every second so the driver sees and recognizes the light for what it is
    in sufficient time to avoid ruining your day.
     
  4. Most bicycle speedometers use a rotating magnet so it's not really a novel
    idea. I just hope whoever thought of plugging a led on the system
    specified stronger magnet fixations than the ones commonly found on
    speedometers, because all the models I know tend to get out of alignment
    now and then when riding down a steep slope on a bad road. And they don't
    work at low speeds - so I guess you should never stop or slow down before
    a road crossing if you don't want to vanish from car sight.

    So I definitely wouldn't trust my security on such a system.

    Regards,
     
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