Brake Light Construction

I figured out how to angle the reflectors for the brake lights. I went to Lowe's and bought the Dremel drill press. It lets me angle the bit up to 90 degrees in increments of 15 degrees. In order to get the slight ovals required so that if someone looked at the LEDs from the back it would be a perfect circle, I drew a CAD model and printed out a template on transparency paper. It turned out pretty good. Just needs some fine tuning and epoxy! Check it out.

Dremel Drill Press.

Drilling with the template.

 Result. I could not achieve a full outer ring because there are screws in those places.

Side view.

I am happy with it. Can't wait to see what it looks like painted and with LEDs in it!

LED 3rd Brake light Completed!

Today I finished my LED third brake light and installed it! It looks pretty good.

Finished brake light.

LEDs on.

Installed on car. Can barely see it through the glass.

It works!

My third brake light is now brighter then the regular brake lights. Well until I finish my LED brake lights!

LED Arrays Constructed

So I constructed two of the five LED arrays so far. Its pretty time consuming because the circuit boards are not prefabricated, its all custom. At any rate, the LEDs look awesome and are super bright! Seriously though, they might be to bright! Have  look.

The arrays. Third brake light (top) and right or left turn signal (bottom).

To much soldering.

They work!

Close up.

Resistors Arrived & Circuit Design!

Today my resistors arrived from www.kelvin.com. I needed 68ohm resistors to run 4 red or yellow LEDs that I received earlier in series. To calculate the resistor value is use the the LED series/parallel array wizard. It is a very nice tool that all you need is the power source voltage, LED forward voltage, LED forward current, and how many LEDs. While this tool is a great help, there are some items to be aware about:

1. Try to maximize the number of LEDs in series in order to achieve higher efficencies (resistors just turn power into heat)
2. Make sure that you power source can handle more then the calculated current draw from the power source
3. Make sure to take note of the resistor wattage ratings in order to appropriately size the resistors
4. Try to keep the same number of LEDs in series across your array in order to make sure that every LED has the same intensity. For example:

 

(wrong)

vs.

(right) 

Keeping LEDs in series even ensures equal intensities.

(image courtesy of the LED Center)

Since a car's alternator outputs a voltage higher then 12v (usually around 13v to 13.8v) in order to be able to charge the battery up to 12v, I will be using a voltage regulation circuit that can handle voltages up to 35v (not recommended) and regulate them to ~12v. Here is the circuit diagram I based my voltage regulator circuit on except that I am using a 7812 voltage regulator (obtained from radio shack):

 

image courtesy of  markallen.

 Now its time for some pictures!

 

New prototyping board!

Voltage regulating components.

 

LEDs! These things a bright, almost to bright!

3rd Brake Build Continued

The epoxy and fiberglass have cured forming a nice structure. One layer seems to do the trick since its not a structural piece. After some preliminary trimming and sanding in my new "isolation chamber" (can be seen on my Project SkimBoard blog), I am almost ready for painting and construction of the LED array. I am still waiting on the appropriate resistors though ( should come Monday!?!).

Third brake light.

3rd Brake Build & LEDs

To test out my reflector design I have decided to make my third brake light the same way I will make the inserts for the taillights. So far I cut and shaped the foam and applied 1 layer of fiberglass cloth with epoxy resin to the front and back. I even got the fiberglass to stick to the reflector curve nicely. Now I just need to trim it up and pint it!

 

Carved and cut foam

 

Pressing the fiberglass with textbooks.

I received LEDs that I order today from superbrightleds.com. I got the 5 mm high flux LEDs in red, yellow and blue! Cost me $70 for 250 LEDs (including shipping). The were fast and they carrier good LEDs. I have had LEDs from other companies die on me after little use.

LEDs! The even gave me a sticker!

Foam Inserts

So I made some foam inserts that fit into the reflector part of the lights. Now I just have to figure out how to cut the reflector part into the foam. The turn signal ones will be pretty easy but the brake light is slanted. I might have to make it flat first. Hopefully a solution will come to me in my dreams tonight...

 

The inserts with a preliminary turn signal sketch...

I really wish I had a CNC machine..... maybe I will make one.... to expensive....

Taillight Baking

So I baked my taillights in the oven to pry them apart. How I did it:

1. Removed all screws that held clear outer lens in place
2. Preheated oven to 300F
3. Baked taillight for 5 minutes
4. Started to pry off the outer clear lens via hands and screwdriver
5. Once glue started to re-harden, baked taillight again for 5 minutes
6. repeated steps 4 and 5 until I completely removed the lens

Here is a link to a You tube video (not mine) that I used for a guide.

 

Without and with outer clear lense

After much baking (4 or 5 times with each taillight) I finally got the outer lens off both taillights. I am pretty happy with he result except that I scratch the housing plastic in a couple of spots with the screwdriver I was using. Now its time to work on those inserts.

Plan

I currently have a 2003 Toyota Matrix XR which I am constructing LED tail lights for. I have an LED 3rd brake tail light but I want a different design. I bought used TYC taillights from a member on the Toyota Matrix Owners forum. My plan is to remove the clear outside lenses by baking the tail lights in the oven and then constructing foam inserts which will be wrapped in fiberglass. I am using foam because its easy to work with and shape. I then plan on reassembling the tail lights.

Hopefully I will not get pulled over by the cops for them.

TYC taillight