/diy/ - Do It Yourself

Wire coils, but i think that no matter the high strenght of the magnets it would be not efficent enough to be of any practical use.

---> http://www.youtube.com/watch?v=b-qiXEM2sRM

http://en.wikipedia.org/wiki/Dynamo

http://en.wikipedia.org/wiki/Alternator_%28automotive%29

>>611813
To quote Mother of Invention, "all the easy stuff is already taken".

>>611810
What kind of bike lights do you use?

Humans produce ~150 watts of power, so if you try and power even 15 watts of lights, you're going to have to peddle noticeably harder when you turn the lights on.

>>611813
>Pendulums
>Same amount of time
>Any angle

Yeaaaaaaaaa have a seat at a basic physics lesson.

>>611810
You'll have to wind two rather substantial coils out of fairly small gauge magnet wire in order to have a shot at this even working, several hundred turns each, and they'll have to be wound tight and perfect, and they'll have to have iron cores. Wire the coils in series with each other. You'll have to manage to get the magnets off their mounting plates, and you'll have to determine North and South poles on them because they'll have to alternate. You'll probably have to fabricate some sort of mounting bracket that will work on spokes. I'd count on one magnet straddling two spokes since spokes are round. You'll want to come up with a way to mount the coils so there is the minimum gap between the coil cores and the magnets as the wheel spins. Here's the tricky part: wheels flex as you ride, so the gap has to be big enough that the magnets don't strike the coils. This gap will reduce the efficiency dramatically, however. Now that you've overcome all these mechanical hurdles, you'll need to make a high-efficiency bridge rectifier. I recommend using low forward-voltage Schottky diodes for this. Now, output voltage is variable with road speed, which isn't so good for a headlight. Have the rectified output charge a large capacitor feeding a buck/boost switching power supply so you get steady output to feed to your headlight.

Total power output? Who knows Build it and see. Oh, and also: The weight of the magnets will dramatically affect the handling of the bike because of the increase in mass of the front wheel. Also, the more power you're generating with something like this, the harder the bike is going to be to ride, because it's not "free energy", you're generating it with your legs.

Or, you could just say "fuck this shit" and get a front wheel with a dynamo hub that generates 3 watts to power your average headlight.

Or, you could say "fuck ALL this shit" and get rechargable lights.

>>611813
>"oh hey this is a bunch of shit we learned how to do, here's the result, I'm not telling you shit about how to do it or how it works but you do it anyway!"
This is totally fucking useless to anyone that isn't a goddamn engineer of any kind and would already know shit like this.