LED Bike Light System

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

Parts:

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

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

Comments

[Objectivityiskey]

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!

[mikeybhang]

"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.

[joe]

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

[LasVegas]

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!

[pyrotecnix]

what value resistor do you recomend then

[kill-a-watt]

try this:

http://led.linear1.org/led.wiz

Without resisters, I'd say those LEDs were getting at least 50 mA each. which can't be good for longivity

[Spokehedz]

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!

[pizzadox747]

wow exgood job dude
cellllllllllllllllent instructable

[bumsugger]

Congrats Joe,a real neat instructable,once again,well done.

[toyotaboy]

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).

[trialex]

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.

[stevexyg]

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.

[trialex]

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.

[carpe_noctem]

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

[stevexyg]

all mine are cheapo ones, that might explain a lot!

[joe]

I purchased these LEDs from Light of Victory http://stores.ebay.com/Light-of-Victory-Led-Store-lvehk , they are listed as "5mm
super bright white LED lamp 55,000mcd "

Curved mirror would be a nice addition to the next version. thanks.

-Joe

[pufferboytbh]

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

[DonTron]

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.

[DonTron]

try here:
http://www.maxim-ic.com/solutions/hb_led_drivers/HB_LED_brochure_final.pdf

[carlitrox]

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

[nikkynixx]

Does anyone know about a company who can do custom LED tail lights for CHEAP (like $100 for engineering)? I tried several companies like Lunar Accents, http://www.lunaraccents.com/applications-custom-motorcycle-LED-tail-lights.html but their engineering fees are steep for an individual like me!!!

[Squash]

That's pretty cool. I don't know much about LEDs but I am looking for someone to instruct me on how to wire my motorcycle with LED turnsignals and possibly the brake light. I want it to be directly hooked to the battery because I don't want anymore bulk like a secondary battery. Bright light!

[joe]

Hey Squash - You could certainly do that, I am pretty sure they sell LED kits for most bikes, I know they do for most scooters. But you could also take some pics of the lights and wiring harnesses and start a new instructable with those. And atleast I would help out with ideas. -Joe