My Custom Led Tail Lights Are Finished

[anemo]

I have now finally finished my custom LED tail lights. I will share some info for you guys who are interested. The project required quite alot of time and hopefully I will save you some if you're planning to build your own... :)

I started out with the schematics. I use high intensity red LEDs from Best HongKong. They are very intensive (25000mcd) but have a drawback: the viewing angle is only 20 degrees. I had my doubts in the beginning but the lens seems to spread the light so it works anyway.

The schematics can be found here.

The LED units were constructed on predrilled experimental PCBs and cut to fit. I used a paper template to create the right shape of the board to fit in the tail lights.

The placement of the LEDs on the PCBs can be found here. I used 28 (4x7) LEDs and masked the lower outer LED to get a more "characterstic" shaped light pattern.

To connect the units to the 7443 socket in the car I used empty 7443 wedge sockets from Autoillumination (found on bottom of page). The units were hooked up according to this picture:

When not braking each LED get around 5mA and when braking each LED get around 20mA (5mA+15mA). I tested the units and the performance was good so I glued them in place in the tail lights. Aligning them was not easy but I finally got them right.

The inside of the plastic lens on the stock tail lights is "bumpy" to spread the light from the light bulb more evenly but this made the light output from each LED very diffuse so I had to coat the inside with epoxy glue to even the surface out. Read more about refraction of light here :)

Before:

After:

The finished result in broad daylight:

The result is quite good but I didn't manage to get a really smooth surface on the inside of the plastic lenses when I coated them with epoxy glue. This distorts the light output abit but it looks good a couple of meters from the car. I think that a couple of layers with clear coat spray would have been better. One thing that I noticed is that the 3rd brake light is always on (but a bit dim) so it's disconnected at the moment. I think that this is the cars way to indicate that the tail light bulbs are faulty since the LEDs draw much less current than a conventional light bulb. This can probably be solved with parallel resistors or reconnecting the 3rd brake light.

I will try to take some more pictures when it's a bit darker outside since the effect looks better than :)

[mi_j]

Great project, think they look good;)

[YarisGLS]

Nicely done! Looks great mate!

But since having done a few LED tail lights myself, I would suggest using superflux leds will be best overall in terms of brightness, angle of beam and low heat generation. Maybe for an upgrade next time you come across this project again? Will be good to swap to use voltage regulators (step up/ down) or LED drivers, instead of resistors to get an even light output even when the voltage varies.

I have worked with Luxeon LEDs too, and the set up will be even easier as only a few is required for more amount of the light output, but heat sinks are required.

Anyway, thumbs up again for such a nice write up on what you did!

[Yaris SR Kid]

Wow custom DIY tail lights1

Kudos to you my friend!

[anemo]

Here are some new (better?) pictures:

As you can see the light pattern is a bit distorted by the uneven surface on the inside of the plastic lenses of the tail lights but I think that I can solve this with a couple of thick coats of clear coat.

The problem with the 3rd brake light always on is now solved :)

More pictures from the project: