Taillights without batteries?

[rfunk]

Since it's often getting toward dusk when I'm riding my bike, it might be a good idea to have some sort of lights on it. I don't ride in the the dark, so headlights are unnecessary, but some sort of flashing taillight might be nice. But I don't want to deal with batteries or switches, so one that uses the movement of the wheels would be good.... such as, for example, the one I had on my old bike.

See, I have an electrical engineering degree (even though I managed to get out of the electromagnetics and power classes, probably the most useful ones outside of an actual EE job). So when I was in a bike shop and saw a taillight that used a spoke-mounted magnet to induce current to make a set of LEDs flash, I HAD to get it. And it worked great. (The model may have been called "Red Alert".)

Then the bike it was mounted on was stolen. And now that I finally have a new one, I've discovered that the light I used to have isn't made anymore. The bike shops have nothing similar, so I searched online.

The closest I found was this one. But it mounts way down on the wheel hub, necessarily interfering with the quick-release mechanism as well as just being visibly too low. And it does look like there's a risk of the thing getting caught in the spokes.

The next closest I found was this setup, which looks like something someone put together in their garage. But other than the ugly homemade look, the technology seems to be a step up from what I had before. (The comparison they have with related technologies is interesting.) If it didn't have such a homemade look and cables running everywhere, I'd jump at this one.

The ultimate technology for this might be a wheel hub generator. Maybe if I start riding across the country....

Comments

[jonobie.livejournal.com]

Yikes, that wheel hub generator has a ton of warnings on it about not touching the hub!

It's always annoying when something that works perfectly well goes off the market. Hopefully you'll find something that suits. I like the look of the solar ones, myself. It mentions something about not charging on rainy days, which surprises me, though -- my little solar powered calculator works okay even when the light is rather dim. What's different?

hub and solar

[rfunk.livejournal.com]

At least the warnings are about not treating it as a normal hub when doing maintenance, rather than about electrocution or something like that. (Unless I missed something.) But there's certainly a disadvantage to swapping out key parts for something nonstandard. Swapping out a wheel hub feels a bit like swapping out a knee.

Where are you seeing the solar stuff?

I'm sure the big difference between the calculator and the light is the amount of power involved (both current and voltage). I guess the rainy day would be sort of like running your car with a bad alternator, damaging the battery. But that's one of those areas of EE (not to mention ChemE) that I'm not so good on. From a totally theoretical point of view, I'd expect that a zener diode could be used to keep the voltage from going below a certain point (other than off).

The solar stuff I've seen talks about charging for 2-3 hours in sunlight, and (for now at least) it's rare for me to ride that long or park that long outside.

Re: hub and solar

[jonobie.livejournal.com]

I was seeing the solar stuff in the comparison chart; it was more that the .idea. appealed to me rather than the specifics. ;-) It never occured to me that running when it was low might hurt something. If you've got to be out in the sunlight for 2-3 hours, that definitely a downside. I definitely was never out that much, especially since I parked inside a parking garage.

Dude...

[taokodr.livejournal.com]

You have a degree in EE...make your own! Radio Shack is calling!

Peace!
GB!

Re: Dude...

[rfunk.livejournal.com]

Good point.

However:
- I'm a bit rusty on the practical side of things.
- Come to think of it, I'm rusty on the theoretical side too, since I left hardware behind for software long ago.
- I skipped the e-mag classes
- I don't like the homemade look
- That sort of project doesn't interest me quite enough to overcome my laziness

Not out of the question, but not likely.

Re: Dude...

[taokodr.livejournal.com]

I guess I can't say much to counter, cuz I bought an electronics learning lab a little over a year ago so I could finally get into it and learn something that I've always wanted to know. I even bought some solar cells and extra LEDs for some cool projects floating in my head.

It's in the box...untouched...for about 8 months now ;-)

*SIGH*

Peace!
GB!