LED Bike Light System




About: I like to tinker with just about anything, sometimes it works out in the end. Have fun looking at the projects, try tearing something open and let me know how it goes. cheers, -Joe

This can be made to be just a headlight or both a headlight/taillight bike light system.

My NiteRider light was off getting fixed at the factory and I needed something for my daily commute. I have used it in a 45 minute pouring rain commute on the way in to work and it worked like a champ.

Step 1: Parts


For headlight:
18 Leds (white 25000mcd)
Small Breadboard
Reflector w/ bracket
9v snap connector

For taillight:
Old Bay Tin
PNP Transistor (3906)
NPN Transistor (2222)
555 Timer
150k resistor
4.7k resistor
1uF Capacitor
160 Capacitor
220 Capacitor
2 x molex KK connectors

Step 2: Solder the Lights In

I am using a 8 AA Battery holder, so thats 12v.
So I soldered 3 white Leds in series to drop the voltage to each led to 4v and be plenty bright.
Make 6 rows of these.
I started on the right side of the breadboard so I could use the left to mount to the reflector bracket.

Step 3: Switch

Drill 3 holes, 2 for the mount and 1 for the switch.

Step 4: Done for Now

I secured the battery pack to my rear rack with a piece of velcro.
You are done if you just want to make a headlight.
I'd say its brighter than my niterider light a 10w but not as bright as it at 15w.

And I gotta be honest, this is a good point to stop. For $6 you can buy a nice Red LED VistaLite blinky. Might as well use one of those, and use this light for the headlight..

Step 5: Blinky

If you want a blinky light, make the blinking light circuit from Bill Bowden's web site: http://ourworld.compuserve.com/homepages/Bill_Bowden/555.htm describes. And I made in this instructable : https://www.instructables.com/id/ED42Y0XZ6BEP286Y2B?ALLSTEPS

Step 6: Rear Leds

Solder your rear LEDs in parralel. Its easy if you just bend the leads on top of each other like so. Make two different arrays of LEDs for the blinking...

Step 7: Mark and Drill Holes

mark and drill the holes in the bottom of your Old Bay tin to mount the rear LEDs

Step 8: Switch

put a switch on the lid of the cannister to turn the rear light on and off, Run a 330 Ohm resistor in line with this to drop the voltage down for the blinky light circuit.

Step 9: Strap

Drill a hole in the cannister to attach the velcro strap to. Use this to secure it to your seat or rear rack.

Step 10: Wire It Up, Cram It In

You are really almost done. Hook the power up, wire it in.

I knew I would not be using the blinky light all the time, so I used 9v snap connectors so I would be able to remove the blinky light, and run it just as a headlight..

Step 11: You Are Done

You could coat the inside of the Old Bay tin with paint or tape so none of the wires short out, I just taped up the 555 ic circuit and called it good.



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    23 Discussions

    Use super capacitors for the energy storage system, and use a step motor from a ink jet printer as the generator. No need for recharging the batteries!


    12 years ago

    "I am using a 8 AA Battery holder, so thats So I soldered 3 white 6 Leds in series to drop the voltage " I don't quite get this. 8 1.5 volt batteries, that's 12V, right? How do you make the LED's match the voltage? I want to mod my motorcycle taillight, and this has been helpful, but some info is lacking.

    5 replies

    Reply 12 years ago

    Mike - Thats a typo, fixed it. Each LED will run off of 3-4v volts. 3 in series is 12 volts. For your motorcycle taillight find out how many volts go to it and findout the voltage requirements of your LEDs. You could also use resitors to drop the voltage. -Joe


    Reply 11 years ago

    The purpose of the resistor is not to drop the voltage, but to limit the current. Without it, the small resistance that the LEDs supply will drive the current much higher than that rated for the LEDs. Depending on the power source, this could possibly lead to LEDs burning out, the batteries having a much shorted life than expected, or fire!


    Reply 11 years ago on Introduction

    yes. Always use a resistor in series with your LED's. Also, this is not the most efficient way to drive the LED's. You want a PWM (pulse-width modulation) of the LED's (turn them on and off really fast) so that way you can get the exact voltage that they need, and change the brightness of them without burning up all the extra volts as heat. ALWAYS USE A RESISTOR WHEN POWERING LED'S!


    Reply 11 years ago on Introduction

    True, I guess it depends on your view of payoff of cost and complexity against gain in light. LEDs will all have a bit of variability too - even amongst LEDs with the same mcd rating my higher quality LEDs have a LOT less spill at the sides than my cheapo ones.


    Reply 11 years ago on Introduction

    if u want to make a reflector cone for cheap, just get some cardstock, glue aluminum foil to it(w/o wrinkling much), and shape it into a rough cone. I think that would be better than nothing


    12 years ago

    Do you have a part number for those LED's? they seem pretty bright. Also you could dramatically improve the light output had you backed it up with a curved mirror surface (think of a headlight on the front of a motorcycle).

    3 replies

    Reply 11 years ago on Introduction

    Probably wouldn't get much of an improvement. A parabolic reflector is used behind an incadescent buld because it throws out light in EVERY direction, so the reflector points the light that would be wasted out the sides and back of the bulb to come out the front, where it is useful. LEDs don't throw light out in every direction. They typically output light in a cone out the front of the LED. If you buy LEDs with specifications they will often stated the theoretical spread, usually 15, 30 or 60 deg.


    Reply 11 years ago on Introduction

    i made a similar light and a reflector did make a big improvement to the apparent size of the light and therefore made you more visable to oncoming drivers. An led does actually emit quite a bit of light to the sides (esp 10mm ones) despite the best attempts of the lens to focus to a certain cone angle. As a quick test u can look head-on at a single led from a distance in the dark side by side with an identical one lodged in a torch reflector - the difference is substantial. On the down-side, a reflector can cut off side visability which would alert drivers to your presence as they approach you from the side ie at junctions/slip roads. Solution is to drill hole/cut slot in reflectors sides.


    11 years ago on Introduction

    I'm Only young but here are my improvements.. Attach a compacitor across the power terminlas. Remeber it's polarised and it would have to be able to hold a big charge


    11 years ago on Introduction

    It is not exactly 'always use a resistor,' 'though that's what it usually amounts to. The proper statement is: 'Always limit the current.' A constant-current source will compensate for battery depletion. A switching CCS would provide greater efficiency, as previously stated, but at the cost of higher complexity.


    11 years ago on Step 2

    Hi, don't need a resistor in the circuit?