Picture of Bike Dynamo
'A simple bike dynamo using a motor as a generator.

WARNING becareful not to get any of the parts from this project caught up in your bike. This dynamo can put out more than 12 volts becareful with your parts or they could get blown.

1 motor 4v (higher voltage is better)
strong plastic lid
hose clamp looks like a metal circle which can be loosend and tightend. choose one to the size of your motor and the size of the bar on your bike.
something electronic like a bulb or buzzer you can test your dynamo on.

Step 1: Attatching the hose clamp.

Picture of Attatching the hose clamp.
Attatch the hose clamp around the bar of your bike put your motor in so it is touching either the tyre or rim. Make sure it stays firmly. If not try wedging something imbetween the motor and bar. See below for more details.
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tscouse2 months ago

U can alter the gearing by the size of the lid U use.The smaller the lid, the faster the shaft will spin.

ThatCatMan1 year ago
:D I have a 12v motor

And I have a loose computer fan to put on the front to get some power as well
The computer fan is hard to get spinning from pure wind,

but then...
I do go pretty fast on my bike....
maybe... Just maybe.....
ksawant2 years ago
wow aewsome explanation
wat is this sposed to do?
generatr electricity while you are riding your bike to power an electronic device...
or ipod lol
isnt ipod electric? or did it run off of wood in the new update?
i meant electric
Lakpahana3 years ago
thanks man keep it up
how to amplify current gain
JumpStart4 years ago
Download SketchUp at Sketchup.google.com for a quick way to draw your bike- and your dynamo! Good luck and Thank you!
Definition of generator:
Engine that converts mechanical energy into electrical energy by electromagnetic induction. So you see, if you turn the motor it becomes a generator.

Also in many cases you have to initially spin the electric motor a little faster than what it turns when you give it power to sort of "kick start" the generation of electricity. But not always.
pyrokid8 years ago
Very good. I can see how it might be a problem to fine-tune one of these, though. I was going to make one of these, but I couldn't figure out how to attach it. Did you get your idea from Tetranitrate's Lego motor generators too?
u might wanna add a diode, so that when stopped, the motor dosen't attempt to turn.
Fat Bagel (author)  pyrokid8 years ago
Hi Thanks for replying. The hose clamps work quite well but yes they don't keep the motor attatched firmly, i think you can use radiator clips or something like that you'll probably be able to work out a good method. Tetranite's Lego generators gave me some help but only with the comments other people added really, like adding some rechargable batteries so the light won't run out when you stop.
Yeah, I basically meant the comments too. you have a very good idea clamping it there with something, i was trying to figure out how to attach it but i had no idea how to. this gave me some very good ideas. Again, great instructable.
thepaul936 years ago
is there a way of telling how much power you get out of it? like with a 3v motor will you only get a max of 3v?
the higher rating a generator has, the more voltage you'll get out of it, but you'll probably never get 3v out of a 3v generator, unless you can rotate the axle as fast as 3v of power can turn the axle. i hooked up a 3v generator from a hand-held fan to my bike, and could only get about 1v power even at top speed. if you want the axle to turn faster, you'll need a series of gears.
It's NOT a generator, but a motor. Please, stop giving false information to people.
ah hah. sorry about that. it is technically a motor, but it does put out a voltage if you rotate the axle.
thanks man great help :)
Im trying to run my electric scooter using bike generator(dynamo) but wont work is there any other way pleasssse helllp me?
Do you mean to trickle charge your battery off the Dynamo or Full on run it off the generator? If A) you want to trickle charge the battery, it will charge verrry slowly so don't expect a huge increase in ride time. Or B) If you are try to run the scooter off of it with no battery, it isn't going to work. The Dynamo would have to be at lease 100% efficient, which is impossible to at this time.
Also, trying to move something with electricity generated by it moving won't work. It has to move to get the electricity to move.
your right 100% is impossible that way by definition due to resistance i.e. friction, but electric heaters are 100% efficient by deffinition because their only purpose is to ecounter resistance cool huh
nf_x207 years ago
hello i tried this with a 9v motor from a cd drive, attached wires to it and ran it to a flashlight bulb, however it does not work when i turn the wheel of my bike. Could someone help please?
sjs229 nf_x206 years ago
it worked for me when i used a 12v motor and 4 leds connected in paralell connection
well, I don't think a little motor from a cad drive is going to do much, they are not designed for the current... You could try using a motor out of an old arc car (motor, NOT SERVO) you could also try gluing the plastic cap to the motor to ensure that it is not slipping. try using a smaller lightblub instead of a bigger motor. and my final piece of advice would be to try it riding faster
pharoah8 years ago
You could just duct-tape. BTW Fat Bagel you spelled tire wrong in your instructable :)
Not in the Queen's English he didn't!
Lol, never realized it was spelled that way across the pond. :)
rae237 years ago
that is truly a work of art
Shouldn't you use a [Example Voltage Regulator] when building something like this?
andrew_297 years ago
dude its a fork not a bar
i hooked up diod bridge and a capasitor to my dynamo so the output would be 12vdc then hooked it up to my motor and test drive but no power?
elescape7 years ago
Not sure if it's been said but you could always wire up head lights and tail lights for night riding.
pinoymale7 years ago
Is the general idea to have the lid come into contact with the tire/rim so that when the tire/rim spins, it also spins the lid?
Pazzerz8 years ago
Go to your nearest Lowes or Home Depot and get a spring loaded mini hinge. Attach the motor to the hinge and the hinge to the frame. The spring loading will keep it against the tire. I used to have a headlight system on my bike when I rode as a kid and it worked exactly like this.
This worked very well i made it in 1/2 hour with a small motor from a cd-rom drive, a hose clamp and a sprite top Great instructable
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