N00b - Help me create a custom 3rd brake light

[boondocksaint]

Hello. Yes, first post. Glorious, I know. I will add pics as soon as I have halfway decent ones taken.

Let me define the situation. I am a car guy. To make a long story short, I want to create a custom 3rd brake light. My car did not come with one on the rear deck (inside the back window). The original 3rd brake light was integrated into a (large, teenager magnet) spoiler. I removed said spoiler, and have no 3rd brake light. My current state of residence does not require one, but I'm a bit of a gypsy and my career tends to move a lot.

SO...

My car has a manufacturer emblem on the trunk face. I am in the process of disassembling that emblem. It consists of a painted clear plastic cap on a cast plastic base. Once I separate the two (which has become a bit of an ordeal :lol: ), I can strip the paint off the cap and have a clear lens (with maufacturer logo cast in it).

I want to backlight this lens after I repaint the highlights. The space tolerance is very slim. I know I need LEDs of some kind. I've read a lot of how-to pages, tutorials, etc. My primary question for you guys is, what LEDs do I use?

Let me go swipe some pics to give you an idea:

The lens is on the right.
(pics removed, you guys get the idea)

And this is an example of it with the paint removed (excepting the silver on the stars).
(pics removed, you guys get the idea)

I've considered a few ways of doing this. I'll list them and you folks can offer input on them as well, if you'd like:

1) Use a translucent enamel or pain of some kind to paint the lens red (with opaque accents) and use white LEDs to backlight it.
2) Keep the lens clear (with opaque accents) and use red LEDs.
3) Use an abrasive to scuff the lens (sans opaque accents) and use red LEDs, whose light will diffuse through the scuffed lens (if that makes sense).

Thank you for reading that obscenely long first post, and for your patience.

 

[TorchBoy]

:welcome:

Yay Subie!

Definitely use red LEDs - there's not enough red in the output of white LEDs to be very effective. Perhaps these ones might do: http://www.dealextreme.com/details.dx/sku.1776

BTW, swiping bandwidth is frowned upon here. :thumbsup:

 

[R33E8]

I would have personally tried to make the 3rd brake light as high as possible. I plan making something similar to the Bentley GT one day:
http://www.zimbio.com/Bentley+Conti.../Bentley+Continental+GT+Style+3rd+Break+Light

Of course I would use Lumiled's superflux leds

Anyways, approximately how much space are you working with?

 

[boondocksaint]

:welcome:

Yay Subie!

Definitely use red LEDs - there's not enough red in the output of white LEDs to be very effective. Perhaps these ones might do: http://www.dealextreme.com/details.dx/sku.1776

BTW, swiping bandwidth is frowned upon here. :thumbsup:

I appreciate the input. Thanks for the link - I'll give it a look tomorrow between the manic amount of work I have to do.

As for swiping bandwidth, I'll break the links in a few days. I don't think the twenty or so page views this thread will get will do anything to him.

 

[boondocksaint]

I would have personally tried to make the 3rd brake light as high as possible. I plan making something similar to the Bentley GT one day:
http://www.zimbio.com/Bentley+Conti.../Bentley+Continental+GT+Style+3rd+Break+Light

Of course I would use Lumiled's superflux leds

Anyways, approximately how much space are you working with?

Mounting the 3rd brake light high is probably ideal, but it's not an option for me. The location of this one will be about two inches lower than the original, so I'm not losing much visibility versus the stock location.

The space is the real issue. I'm going to be modifying the backing piece to gain a little clearance. Even so, we're talking a couple of millimeters. Think 5 or 6. There are a few ways I can trim it to fit a bit more if necessary. The goal is for the face to look clean and stock-ish. What the back looks like, well, no one will see it once it's installed.

Thus, for now, I'm looking for low profile parts. Stuff that's very flat.

I'm going to dedicate some time Sunday to pulling it apart and, when I get it there (be patient, I'm a clutz), I'll post new pictures.

Thank you guys for posting. I appreciate it. And if either of you like Subies, visit IWSTI. I'm a mod over there.

 

[LukeA]

I'd back the logo with something translucent white.

 

[sed6]

Your idea for the 3rd brake light is cool. I presume it's on the upper edge of the trunk, hopefully centered? I'd go with translucent red background, opaque accents and red led's, here's why. Almost any led/light that close to the surface is going to create real 'hotspots'. That is to say a led inside the emblem, 1-2mm from the surface will look like a hotspot. You'll get somewhat decent 'glow' from the emblem but it'll be peppered with hotspots (depending on how many leds you use). Red translucent paint (like for painting RC car bodies) and red led's should help minimize it. Though if I were a betting man, I doubt you'll be happy.

Instead you might want to try something else. What about cutting a hole in the trunk, about the size of the emblem, and creating a light-box/reflector behind it. Think about old style side marker lights, or even a fog light, they have a bulb set back several inches from the lens, contained in a housing. Where a fog light uses a high power bulb and a side marker uses a fancy lens, both focus and smooth the light for a particular purpose. If you had a similiar enclosure behind the emblem you'd provide a nice even light and create a pleasant red glow with the opaque parts standing out nicely. I mean why not, you're not ever going to undo this mod, so a hole in the trunk shouldn't matter.

OR...here's a guy that did a glowing emblem on his 626 using led's. Looks thin enough for your purposes... http://www.hobbyguild.com/timp/mazda/emblem.html

 

[sed6]

OR...here's a really thin led 'board'. Supposed to be used as a dome light, but I bet you could use it; I see several sizes... http://www.oznium.com/thin-led-domelight

OR even this... http://www.allightech.com/6INCH OVAL.htm

 

[TorchBoy]

As for swiping bandwidth, I'll break the links in a few days. I don't think the twenty or so page views this thread will get will do anything to him.

Already there have been 30 views, which makes about 5.6MB. But however much or little, it's still something we're asked on this forum not to do. Would you like me to temporarily host them for you?

If it needs to be really flat you'll probably want lots of light sources, not just one or two really bright ones. I'd tend more towards a translucent diffuser rather than an opaque flat colour, as that might cut the light down too much.

 

[boondocksaint]

Your idea for the 3rd brake light is cool. I presume it's on the upper edge of the trunk, hopefully centered? I'd go with translucent red background, opaque accents and red led's, here's why. Almost any led/light that close to the surface is going to create real 'hotspots'. That is to say a led inside the emblem, 1-2mm from the surface will look like a hotspot. You'll get somewhat decent 'glow' from the emblem but it'll be peppered with hotspots (depending on how many leds you use). Red translucent paint (like for painting RC car bodies) and red led's should help minimize it. Though if I were a betting man, I doubt you'll be happy.

Instead you might want to try something else. What about cutting a hole in the trunk, about the size of the emblem, and creating a light-box/reflector behind it. Think about old style side marker lights, or even a fog light, they have a bulb set back several inches from the lens, contained in a housing. Where a fog light uses a high power bulb and a side marker uses a fancy lens, both focus and smooth the light for a particular purpose. If you had a similiar enclosure behind the emblem you'd provide a nice even light and create a pleasant red glow with the opaque parts standing out nicely. I mean why not, you're not ever going to undo this mod, so a hole in the trunk shouldn't matter.

OR...here's a guy that did a glowing emblem on his 626 using led's. Looks thin enough for your purposes... http://www.hobbyguild.com/timp/mazda/emblem.html

I am afraid of hot spots, and I'm glad you brought them up. This is why I considered the translucent paint and scuffing the lens to diffuse the light, but I wasn't sure if it was going to be enough.

Thank you VERY much for the link. I'm going to have to read that one as well. I took a peek, and the result pic was pretty damn cool. As far as my own purposes, we're in luck. The ONLY reason the Subie badge is still on the car is that the trunk has TWO holes in it for the badge. :lol: Otherwise I would have simply debadged it.

The holes are about half an inch in diameter about twi inches apart, located on the upper half of the emblem backing plate. That's why I think this link will be really helpful.

This is exactly what I was hjoping for when I signed up here.

 

[boondocksaint]

OR...here's a really thin led 'board'. Supposed to be used as a dome light, but I bet you could use it; I see several sizes... http://www.oznium.com/thin-led-domelight

OR even this... http://www.allightech.com/6INCH OVAL.htm

Great links again. I have seen the latter on another site. Google was my only friend in this project until Captain Obvious asked me if I'd tried to find light mod forums. :lol:

 

[boondocksaint]

Already there have been 30 views, which makes about 5.6MB. But however much or little, it's still something we're asked on this forum not to do. Would you like me to temporarily host them for you?

If it needs to be really flat you'll probably want lots of light sources, not just one or two really bright ones. I'd tend more towards a translucent diffuser rather than an opaque flat colour, as that might cut the light down too much.

I removed them. They'd served their purpose and I didn't want to anger the forum gods here. I have a metric (bleep)-ton of work to get done today. I hope that, later in the day, I will have time to read all of these awesome links in their entirety, take some real pics of the emblem I have, and maybe even get the damn thing apart.

You guys are awesome. Thank you again for the help.

 

[boondocksaint]

Okay, today has kicked me in the teeth. I'll get on this tomorrow.

:|

 

[boondocksaint]

Well, I've spent the better part of the morning trying to get the lens off the backing plate. I've used tiny tools and dental floss - or I've tried to.

Despite my best efforts, the thing just will nto come apart. To top it off, I've created some noticeable tool marks on the piece. This is really pissing me off, but the good news is that the piece I'm using is a spare. I still have one on the car.

So, I need to figure out a way to get the bloody thing apart without destrying it before I can continue my modification plans. Suggestions welcome.

I'm on vacation for most of next week, so I won't be checking daily.

 

[LukeA]

I am afraid of hot spots, and I'm glad you brought them up. This is why I considered the translucent paint and scuffing the lens to diffuse the light, but I wasn't sure if it was going to be enough.

Thank you VERY much for the link. I'm going to have to read that one as well. I took a peek, and the result pic was pretty damn cool. As far as my own purposes, we're in luck. The ONLY reason the Subie badge is still on the car is that the trunk has TWO holes in it for the badge. :lol: Otherwise I would have simply debadged it.

The holes are about half an inch in diameter about twi inches apart, located on the upper half of the emblem backing plate. That's why I think this link will be really helpful.

This is exactly what I was hjoping for when I signed up here.

That link is good, but don't listen to the guy about wiring it. He assumes the car runs 12.000V, which is not the case, and your standard 5mm LED can't handle the resultant current increase through the resistor from the car system voltage in actuality being around 14V.

(I only skimmed the link, so he might end up correcting himself)

EDIT: He doesn't. And I don't think he fully understands the concepts involved. But he does assume a ridiculously low value for the Vf of each LED, so they end up not overdriven.

 

[boondocksaint]

^ Yeah, I know how the power fluctuates. My head unit has a volt gauge built in. It goes between 13.2v and 12.1v depending on what accessories are powered, if the lights are on, etc.

 

[boondocksaint]

So I'm on vacation and I'm not tired, but I have nothing to do. So where do I end up? Forums. Sad, I know. :lol:

So I thought I'd dig out some photos and show you, at least, what car this is going on. The bandwidth is used with permission.

And in this one, you see where this project will be going.

So, at least I accomplished something tonight, even if it was just whoring out pictures of my car. I'll be back home late this weekend and ready to take another stab at getting the badge apart.

 

[Ken_McE]

Gorgeous car. Would you consider going at this differently? How about the emblem lights up in blue and just stays on with the running lights. Run a strip of red LEDs all the way across that bar that runs along over the rear window, use that for the third brake light.

 

[boondocksaint]

Gorgeous car. Would you consider going at this differently? How about the emblem lights up in blue and just stays on with the running lights. Run a strip of red LEDs all the way across that bar that runs along over the rear window, use that for the third brake light.

Thanks for the compliment. I would rather not have the emblem always on. Also, the reason I am putting the third brake light there in the first place is that I don't want a LED strip or a regular old lamp on the rear deck a la any other car. Call me crazy.

Okay, time for the end of my vacation. I'll check back with an update shortly.

 

[TorchBoy]

How come the badge has a blue background, not pink?