Introduction: Bike Dynamo

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.

Step 2: Testing and Troubleshoot

Picture of Testing and Troubleshoot

Test your dynamo conect the motor wires something you want to power. Then start riding. See below for more details.

This is my first instructable. Sorry about not having real pictures but that is what it looks like except for the crappy bike drawing.


tscouse (author)2015-06-11

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

ThatCatMan (author)2013-11-20

:D I have a 12v motor

And I have a loose computer fan to put on the front to get some power as well

ThatCatMan (author)ThatCatMan2013-11-20

The computer fan is hard to get spinning from pure wind,

but then...
I do go pretty fast on my bike....
maybe... Just maybe.....

ksawant (author)2013-01-10

wow aewsome explanation

whiteboipumas (author)2007-05-02

wat is this sposed to do?

girrrrrrr2 (author)whiteboipumas2007-08-01

generatr electricity while you are riding your bike to power an electronic device...

xproplayer (author)girrrrrrr22007-11-02

or ipod lol

girrrrrrr2 (author)xproplayer2008-10-09

isnt ipod electric? or did it run off of wood in the new update?

Adambowker98 (author)girrrrrrr22012-06-13


xproplayer (author)girrrrrrr22008-10-09

i meant electric

Lakpahana (author)2012-04-12

thanks man keep it up
how to amplify current gain

JumpStart (author)2011-01-27

Download SketchUp at for a quick way to draw your bike- and your dynamo! Good luck and Thank you!

lordgarion514 (author)2010-10-06

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.

pyrokid (author)2007-01-17

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?

luigi2999 (author)pyrokid2009-03-29

u might wanna add a diode, so that when stopped, the motor dosen't attempt to turn.

Fat Bagel (author)pyrokid2007-01-17

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.

pyrokid (author)Fat Bagel2007-01-17

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.

thepaul93 (author)2008-10-22

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?

rotf101 (author)thepaul932008-12-26

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.

snowpenguin (author)rotf1012009-03-27

It's NOT a generator, but a motor. Please, stop giving false information to people.

rotf101 (author)snowpenguin2009-03-27

ah hah. sorry about that. it is technically a motor, but it does put out a voltage if you rotate the axle.

thepaul93 (author)rotf1012008-12-28

thanks man great help :)

snowpenguin (author)2009-03-27

A big enough motor will, yes.

inneedofhelp (author)2008-04-25

Im trying to run my electric scooter using bike generator(dynamo) but wont work is there any other way pleasssse helllp me?

Retroboy4 (author)inneedofhelp2008-06-20

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.

snowpenguin (author)Retroboy42009-03-27

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_x20 (author)2008-01-30

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 (author)nf_x202009-01-21

it worked for me when i used a 12v motor and 4 leds connected in paralell connection

Junk_Wizard (author)nf_x202008-05-17

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

pharoah (author)2007-04-15

You could just duct-tape. BTW Fat Bagel you spelled tire wrong in your instructable :)

cbelectron (author)pharoah2008-06-25

Not in the Queen's English he didn't!

pharoah (author)cbelectron2008-09-06

Lol, never realized it was spelled that way across the pond. :)

rae23 (author)2008-08-21

that is truly a work of art

Handsome-Ryan (author)2008-08-01

Shouldn't you use a [Example Voltage Regulator] when building something like this?

andrew_29 (author)2008-07-24

dude its a fork not a bar

inneedofhelp (author)2008-04-25

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?

elescape (author)2008-04-21

Not sure if it's been said but you could always wire up head lights and tail lights for night riding.

pinoymale (author)2007-10-06

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?

Pazzerz (author)2007-08-21

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.

sam_rocks321 (author)2007-08-16

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

KD7WHQ (author)2007-07-13

A DC motor will generate electricity no matter which direction it is turned, or the lead connections...unless there is a diode actually inside the motor itself. Spin it one way, you get electricity. Spin the other, you get same at reverse polarity..

SacTownSue (author)2007-06-23

To keep things from moving around and shaking loose try putting something rubbery around the motor between the clamp. Something like shelf liner, rug anti skid or how about making rubber bands out of an old bike inner tube. I bet you can find an old bike inner tube without looking too far. Great idea for an instructable. I remember seeing these as a kid and have thought about them since but didn't realize it was so simple. I'm gonna try this.

hockeyteeth (author)2007-03-02

Add capacitors (they can store energy generated by the dynamo) to the circuit. I don't know how you power anything with the electricity stored in the capacitor, but it would prevent the light from dimming.

Fat Bagel (author)hockeyteeth2007-03-09

thanks. I don't know that much about electronics so i doubt ill be able to do that but it sounds like a good idea.

Fat Bagel (author)2007-01-18

Yeh you'd have to add some rechargable batteries to the circuit. I don't know how you stop it from going light to dim. Someone smart will work it out

dirtdawg (author)2007-01-18

Good one, I had a similar thing on my bike when I was a kid.It came from Sears&Roebuck.The; problem was,when you stopped the light went out,and the voltage varied with your speed making the light bright or dim.

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