More LEDs!

So I am still trying to figure out how to the heck to make this thing look good. So I am now thinking that if I get a typical cylindrical LED instead of these high flux square ones, I might be able to just drill holes and slide the LEDs through the back of the foam insert. I think this might work the best....

So I bought various LEDs from superbrightleds.com and have been seeing which one is the brightest. I got a couple different ones:

Viewing Angle
360                     8mm          (RL8-R25-360)
120                     1200mcd    (RL5-R12120)
45                       3500mcd    (RL5-R3545)
30                       8000mcd    (RL5-R8030)

I am really interested in how the viewing angle affects the brightness.

The order from top to bottom (360, 120, 45, 30).

Same order, farther away. Like all my junk? lol.

These images do not look like the LEDs look in real life.... I think the 45 degree LED looks the brightest, well perceived brightness.

I replaced the 120 degree LEDs with the square high flux LEDs. I think the 45 degree LEDs look the best out of the bunch. Time to buy more LEDs!

Update

I haven't posted on here in a while. Unfortunately, I am not too happy with the way the foam turned out. it is to soft and does not look good. Even with the epoxy on it. I am currently experimenting with 0.22" acrylic from the local Lowe's. Hopefully it will turn out better. If not I'll be needing to find a different material.

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.