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How to: Build your own custom LED Tail Lights

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This guide is intended to be simple and straightforward. It's intent is to show you how to build a simple dual intensity brake light LED board. I have completed 6 assemblies using the same components that I am listing for this build, with great success and not one LED failure.

Feel free to ask questions if you need something clarified... i'll re-edit the post and make things more clear.

Tools/supplies needed:

-good soldering iron

-solder with resin core (helps solder adhere and clean)

-good small wire cutters

-wire stripper

-small gauge wire (18-20)

-chrome spray paint

-Radio shack diodes (1/2W each)

-Radio shack resistors (46 Ohm 1/2Watt and 100 Ohm 1/2Watt)

-Radio shack perf board (more on this later)

-Superflux LEDs (about 30-60 red/orange superflux. Use genuine Lumileds. www.LEDCAR.com Part number: HPWT-DH00-G4000) You can also find people selling them for $15-20/per 60 on HID planet.

-Holiday red, green and blue table cloth. Merry Christmas. ;)

Tools.jpg

Resistors:

Basically, the more resistance the less light. So I chose 46 ohm 1/2Watt resistors and 100 ohm 1/2W resistors. I chose to run 4 LEDs in each circuit. I will hook the resistor up to the + side of the circuit and then wire each LED in series. At the end you see a purple ground wire (eventually hooking up to a big black ground wire).

Here is the circuit.

Schematic1.jpg

You can see from the schematic, that there are two circuits. One for brake and one that is always on for the running light. The brake light bypasses the 2x100ohm resistors (50ohm) and uses just the 46ohm resistor. (less resistance = more light)

For the running light you have the 2x100ohm resistor and the 46ohm resistor. This gives you a total resistance of 96 ohms for the running light. When resistors are in series, you can simply add the resistance.

What thought process went into this? I first calculated what would be safe current and voltage to run through the circuit of 4 LEDs. Then i figured out what looked good. It is safe to run as low as 36 Ohm for the brake light. This will make it just slightly brighter, but will run more current through the LED, and could decrease life. The combination of the 100ohm and 46 ohm to give me 96ohm total resistance for the running light was not calculated. I tried to see what would make the light significantly dimmer. This worked.

So,,,on to the build.....

Typical housing.

catskills002.jpg

I actually have a 50LED strobe that replaces my lower bulb. Ignore. It does not affect this build.

Heat the oven to the lowest temperature it will go. For my oven that is 250 Degrees F. DO NOT PLACE THE ASSEMBLY IN THE OVEN WHILE IT IS HEATING. The oven gets significantly hotter in certain spots. Preheat.

Place the assembly in after the oven is heated. Leave in there for 10 mins.

Pry the lens from the housing.

catskills004.jpg

For me, this retrofit will be for the top bulb only. Grab your Radio Shack perf board (common item) and hold it up to where it needs to fit. Trim the perf board to fit.

I used a big dull set of wire clippers. The Dremel makes a huge mess.

Smooth the edges with the Dremel.

catskills005.jpg

Make sure you take a good long look at the angle this board will need to sit. If you direct the board straight forward, it will be very upright when mounted on the bike. I'd recommend doing the trimming of the board with the housing on the bike.

When you are happy with the size of the board, give it a light coat of chrome spray paint. Only paint the side that the LEDs will be mounted on. Traffic facing side.

catskills007.jpg

catskills008.jpg

Now we're getting somewhere...

catskills009.jpg

I hit the paint with the heat gun so that the paint bakes on and dries quickly. But if you can wait an 2 hrs, thats cool too.

Place your LEDS in a pattern that you like. Think ahead, since you will need to link them together in pairs of 4. Make sure you have a number that can be divided by 4. 8, 12, 16, 20, 24, 28....you get the idea. You can put as may circuits on this board as will fit your budget. That is up to you. I believe I chose 24 or 6 circuits of 4.

Now,,,while you are placing them, keep in mind they should all be placed facing the right direction. Why? Time for some LED 101.

Here is how they come,,,in a tube of 60.

catskills010.jpg

catskills011.jpg

catskills012.jpg

Notice they have 4 contacts. 2 postive and 2 negative. You only need to hook up 2 contacts. 1 positive and 1 negative. Four contacts are there for heat dissipation and for ease of hooking the LED into a PCB. Don't worry, it will be fine with 2.

Important: The positive side of the LED is the side with the two small holes through the metal on the inside of the lens. You can see this in the pictures.

wiringschematic.jpg

Here is how you will end up wiring them up. (more on this later)

Schematic1.jpg

Not sure why i picked this pattern,,,but it ended up looking good.

catskills013.jpg

The LED's are now all loosely stacked into the board in the pattern you like. Place a hardcover book on top of them, and flip the board over, so they will not all fall out. Now bend over the ends of the LED leads, so they stay on the board.

catskills014.jpg

Your circuits should look like this, repeated as many times as you need.

NewPicture1.png

When you are done, it should look like this.

catskills019.jpg

The wires sticking up are the resistors. I wired them through the board to make things neat.

You will solder a wire to each of these resistors. This will be ultimately attched to the brake light. This is your 46 ohm circuit.

Ground wires soldered to the end of each circuit (purple wire)

catskills020.jpg

Brake light wire soldered to each resistor (striped)

catskills022.jpg

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Hey I got those same pliers. Nothing helpful to add. :icon_whistle:

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Now you have all of the hot wires soldered and all of the ground wires soldered.

Test each circuit with a 9V battery. Reversing the poliarity will not hurt the LEDs. You can't blow anything up.

Now what you are going to do is solder all of the like wires to each other and make them have one common wire. What you want is 1 ground wire and 1 brake light wire (hot).

I joined all of the ground wires together and soldered them to a large black wire. I joined all stripped wires together and attached another stripped wire.

catskills025.jpg

Feel free to shrink wrap or electrical tape wrap the ground wires connection. You're done with it.

So where the hell does my other wire come from? Right now i have just a ground wire and a brake light wire. I need running lights. Well here's the scoop...but first you need to learn about diodes.

Diodes.jpg

Diodes:

Diodes allow voltage to flow one way and not another. By installing diodes, you will be able to prevent any fuses blowing when you apply the brakes or have your running lights on. You will be installing another wire with resistors and diodes at the same connection where all of your hot, brake light wires come together.

catskills026.jpg

Every diode has a line on it. You want to point that diode toward the circuit you need to energize. Think of that diode as blocking the path, back to the bike but letting it go to the lights. I used two soldered in parallel to make sure I have enough current protection.

catskills027.jpg

Put that aside for a second and solder your resistors. Again, these are two 100ohm 1/2W resistors which make up 50ohm is total resistance. In parrallel they provide 1 W protection.

Now solder the resistors and diodes together. It doesn't matter which goes first.

catskills030.jpg

Solder the diodes and resistor to the bundle of hot wires that come from the brake circuits.

Remember: the line on the diodes must face the circuit on the board.

catskills035.jpg

Wrap the connections in shrink or tape.

catskills036.jpg

This is what my wires now look like.

catskills042.jpg

Black = Cluster of ground wires

Red = Running light (diodes and loose 100ohm resistors, hooked to the stripped wires)

Stripped wire = Brake light (circuit on the board with 46 ohm resistors)

If you have a battery nearby (12V car or bike), go ahead and test to make sure it all lights up.

Success!!!

catskills040.jpg

If you did things right, you should be nearly blinded by looking directly at the brake light. Its pretty insane!

catskills041.jpg

Now you need to hook up the completed LED board to the bike. I chose to solder my wires to the connector. Here is what your connector looks like.

catskills043.jpg

Here is what wires go where.

NewPicture2.png

Make sure you get enough heat into the connector so the wires bond well. Tug on them so you can make sure everything is sound.

Now you need to secure the board to the housing. I used a hot melt glue gun.

catskills046.jpg

It came out looking pretty clean!!

catskills047.jpg

Place the lens back on the housing and head to the garage to make sure it works before you glue the lens to the housing.

running light

catskills048.jpg

brake light

catskills050.jpg

RTV the lens back onto the housing and you should be good to go.

Enjoy your added visiblity on the street!!!

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Just one minor nit-pik: two 100 ohm resistors in parallel equal 50 ohms, not 100 ohms.

Formula: 1/ (1/R1 + 1/R2) = 1/(.01 + .01) = 1/.02 = 50

You do have 1 Watt, but at 50 ohms, not 100 ohms.

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Just one minor nit-pik: two 100 ohm resistors in parallel equal 50 ohms, not 100 ohms.

Formula: 1/ (1/R1 + 1/R2) = 1/(.01 + .01) = 1/.02 = 50

You do have 1 Watt, but at 50 ohms, not 100 ohms.

Good catch,,,you're right. Will update!

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Fantastic Write Up.

Question: How do the leds "know" to get brighter then the barke light is applied, are they two stage leds? or is it a voltage resistance thing? ie more current running through them when the brake light is applied..

Sweet post.. thanks.. and great job...

heading to Radio shack to mess around now...

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Great write up. I have the LED's in my shop for the same type project.

I remember reading where people would put the tail light in boiling water to loosen the glue and remove the blank plate under the lens. They were removing

the tag light, by putting a clear lens in the bottom of the tail light. If 212 degrees is enough for the blank plate, it might be enough for the complete lens.

I need to get out my Newark book and learn about new style LED controllers. I want to make mine pulse when the brakes are applied. Still living in the 555

timer/TTL days. :icon_redface:

I had also thought about using some plexiglass, with metal contacts to build a plug the same size as the bulb base, just plug into the socket instead of soldering.

Now if I could find a used tail light to play with.............

Looks like you used 28 LED's how does it compare to the bulb for visibility from the rear and side?

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Fantastic Write Up.

Question: How do the leds "know" to get brighter then the barke light is applied, are they two stage leds? or is it a voltage resistance thing? ie more current running through them when the brake light is applied..

Sweet post.. thanks.. and great job...

heading to Radio shack to mess around now...

Thanks!

No. The brake light applies the same voltage/current as the running light. The only way they 'know' to be brighter or dimmer is by changing the resistance.

That is why there are two circuits. Brake lights have 46ohm resistance and running lights have 46ohm + 50ohm (the two 100ohm).

Less resistance = more light

Great write up. I have the LED's in my shop for the same type project.

I remember reading where people would put the tail light in boiling water to loosen the glue and remove the blank plate under the lens. They were removing

the tag light, by putting a clear lens in the bottom of the tail light. If 212 degrees is enough for the blank plate, it might be enough for the complete lens.

I need to get out my Newark book and learn about new style LED controllers. I want to make mine pulse when the brakes are applied. Still living in the 555

timer/TTL days. :icon_redface:

I had also thought about using some plexiglass, with metal contacts to build a plug the same size as the bulb base, just plug into the socket instead of soldering.

Now if I could find a used tail light to play with.............

Looks like you used 28 LED's how does it compare to the bulb for visibility from the rear and side?

For the blinking, you are on your own!! :)

Boiling water? That sounds too messy for me. The oven works very well to release the housing.

It seems pretty good. Thats what is nice about the superflux LEDs. They are disperse light much better then your standard 5mm LEDs,,,,about 90-120 degrees coverage.

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Great write-up! I bet you could sell a few of those done if you wanted to make a few bucks.

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As good a place as any to ask if anybody knows how to do a sequential led... for turn siginals. Can't find how or any to use.

Great writeup. Needs to be in the useful section...for posterity.

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As good a place as any to ask if anybody knows how to do a sequential led... for turn siginals. Can't find how or any to use.

Great writeup. Needs to be in the useful section...for posterity.

I highly recommend going to the LED section of HID forums. Those guys do anything and everything with LEDs. This is where i learned about the really good superflux LEDs and a host of tips about projects like this.

Sequential is not easy. You need a PCB controller and a good power supply.

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FYI: People selling tubes of superflux LEDs for as low as $5 per tube. ($.08/each)

http://www.hidplanet.com/forums/viewforum....=0&start=25

WTB HID forum.

http://www.hidplanet.com/forums/viewforum....s=0&start=0

Great write-up! I bet you could sell a few of those done if you wanted to make a few bucks.

I'd entertain the idea during these cold, non-riding months up here in the NorthEast.

Anyone interested can PM me.

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Good Job.

I look forward to trying my hands at that, sometime in the future...

Hopefully then I'll be able to find this thread again.

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Maybe a Moderator could move this into the Important/Useful Threads section.

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Good idea, Mike. Once this starts working it's way down the page I'll move it. Better visibility here for now.

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That kicks more ass than a donkey!

Wicked cool. :icon_clap: Thanks for sharing that, I'm going to have to try it out on the front signals... Nice winter project.

Thanks again!

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That kicks more ass than a donkey!

Wicked cool. :icon_clap: Thanks for sharing that, I'm going to have to try it out on the front signals... Nice winter project.

Thanks again!

Thanks guys.

I actually already did my front turn signals. I used the same red/orange LEDs because i did not have amber on hand, and i was impatient. The red/orange LED's actually look pretty cool through the amber turn signal housing.

They are super bright. I have found that alot of cars pull out of my way very quickly. I love them and am glad i used the red/orange LEDs.

You can see the glare in the camera from this pic.

MtWashingtontrip275.jpg

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Great job, but why not just get the unit from High Tech Speed Lights with the controller box? Sure you save some cash but look at the time it took to make and the aftermarket unit is very robust, likely much more robust than the home made item (solder joints etc.), programable and bolts right in all plug and play without any cutting of wires or modding of plugs etc.

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F4i, thanks for posting this. I finally got all the materials together and ran a test on 1 circuit today. Worked like a champ!

I'm going to be replacing the running lamps on my trailer first, there are 2 that have been an ongoing PITA with bad connections. Now I'm replacing the entire bulb ass'y with these.

Best thing is that LED trailer lights are $20. Cost of this rig is under $2 per lamp. More cash to blow on my, um, transgressions.

And for those who are loving the premade LED lamps, while they look and work real neat, the cost for them is astounding. I'd rather do this, and keep the cash for tires.

Thanks again!

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I was looking to refine the design of this, and found another site. I have not (yet) tried any of these schematics, and would very much appreciate comments on them

All Auto Circuits: http://www.redcircuits.com/Auto.htm

Basic Tail/Brake Lights: http://www.redcircuits.com/Page85.htm

Sequential Brake/Turn Lights: http://www.redcircuits.com/Page128.htm

And another site that modulates LED flashing to control brightness: http://www.reuk.co.uk/LED-Dimmer-Circuit.htm

Any thoughts on these?

Gracias!

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You're welcome! I have alot of fun playing with this stuff, and if its not fun then its not worth doing! :)

One correction i should add to this write up, is that you should leave some space from the top of the PCB to the first row of LEDs. Turns out you can't really even see the first row since the rear cowl actually comes down over the top of the brake light. Oh well..still looks good, but if I had to do over i would change that one thing.

My brake light is working like a charm. Good to go.

In order to change the brightness of the LED you can use a PWM. It modulates the pulse of the light so that it appears more dim or bright. I choose a $.01 resistor. IMHO, the simpler the better.

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