Home made Bicycle Dynamo light Overview

I made a bike light that is powered by my wheel spinning, not batteries. You can buy these, they are called dynamos. I just wanted to make one myself. The power source is a small DC motor I salvaged from a computer printer someone threw in their trash. I modified the output shaft of the DC motor so that I could screw the speedometer cable directly to it, without any added gearing. as my wheel spins it turns the speedometer cable, which then turns the motor. I wired the motor to a small 9 led flashlight that someone gave me. when I start peddling my light turns on. when I stop, the light stops. No more batteries for me. The light is primarily not to see, but to be seen by cars and other bikes easily. The street lights all over Portland, OR are good enough to see.

Category:

Science & Technology

Tags:

• bike light
• dynamo
• bicycle light

[kevbriga]

this motor i used came from a printer and is DC. I am aware that most printer motors are AC. my led lights light without a bridge rectifier circuit so the electricity produced is DC.

[kevbriga]

this motor is a DC ri

[MrJustCollin]

Pimp.



[joselu90]

You are only using a half of the steeping motor or your motor is an alternator, when it spin, only you only gets a half of the energy that you are producting

[yayo65]

i think you can add a capacitor in paralell with the motor to reduce that strobe effect

[KD8EDR]

@kevbriga The LED's in most flashlights like that are just wired in parallel so all turn on at the same time. LED's will light up with AC, they are diodes so when the current is reversed biased, they will just be off, and then when polarity is reversed again they will be ON. If that is a stepper motor the signal is AC coming from the terminals. Why it strobes at low speeds is because the frequency of the AC is so low, that you can see the LEDs turning on and off. :-)

[coolkid1261]

its a ac motor because motors im printers are ac motors and btw those flash lights have all LEDs on at once and ac currents make them do that.

[OLDSKOOL559]

Nice vid I enjoy watching it I love when people actually explain what they are doing :) keep up the Gud wrk !!!

[Fishman13452]

I commend your ingenuity but are you aware that there are hub's available which do exactly what you are attempting ..... called dynohub's .

Not to take away from your very creative solution ......... but a dynohub would be more efficient Ie. produce more electricity for less effort and can be found on ebay pretty cheaply ... and can sometimes be had for free if you keep your eye's open.