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Scrolling LED Third Brake Light!

Picklz

Picklz

SUDO Make me a SAMCH
Alright so a few of us are entertaining the idea of setting up the Third Brake light in the MS3 (which is an LED light) To scroll back and forth, or knightrider style. Right now we are in the planning stages, we have a couple options. One would be a completly custom controller and light setup. This would give us the greatest flexibility and controll, but would also require the most work in the form of programming a microcontroller to control the LED's as we see fit. Second option would be to find some type of LED controller or pre-made Lightbar that already has a controller in it, and modify it for our use.

Quick update:

At the moment for a first run we are looking at the following for features:
1) At least 1 scrolling / chasing pattern when you step on the brakes, needs to stop after 5-6 seconds and become solid.
2) If we go with more than 1 pattern, a button or switch will need to be used to switch patterns.
3) Ability to disable scrolling feature completly so the 3rd light works as a standard on / off light
4) Ability to turn on / off a feature to have the 3rd brake light scroll a pattern while the vehicle is shut off, at a lower brightness.

If there are multiple patterns some sort of indicator such as a row of LED's near the instrument cluster, or integration with the Radio LED's would be great, but I think we are going to leave that for an add-on type situation once we get the main part of the project working.

I found this which has some potential, but I'm open to ideas or suggestions
http://www.chromeglow.com/catalog.asp?prodid=543501&showprevnext=1

Here's and example of a fairly simple controler someone built, complete with code. It would need to be modified for our use a bit, and to support more LED's but it might be a starting point. Thanks to Jay for this link.
http://home.wanadoo.nl/electro1/avr/kitt.htm

I'm looking into PIC programming right now, if anyone has experience with that let me know.

Post #11 Has some basic LED and Electronics Info in it for those interested, if there's anything anyone would like added let me know. I'll be updating it over the next day or two.

dmention7 said:
Might as well post up the original inspiration for this thread (Colin actually showed it to me)

http://www.youtube.com/watch?v=K6sZg3iL5EY
Click to expand...
 
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Picklz

Picklz

SUDO Make me a SAMCH
pffft I can manage this....I think...but yeah Jeff could probably whip that up in 30 seconds flat.
 
Young Roids

Young Roids

Banned
Reminds me of those add on led signs that scroll messages like the bank signs only ones for your car. I saw a dude in a blazer on Daytons with the message scrolling "I have no weapons and no drugs in the vehicle. Leave me alone." It gave me a laugh.
 
Young Roids

Young Roids

Banned
That really works well with the eclipse rear light design how they go accross the whole rear of the car. BUt I wonder if the cops would give you touble with that setup.
 
mndsm

mndsm

I'M OFFENDED!
As long as you weren't doing stupid shit with it on the highway and letting it function as brakes/turn signals, I don't see how they could. It's definately within DOT guidelines for brightness and it is the right color, so unless you had it strobing or something like a cop car, they'd probably let you go.
 
dmention7

dmention7

Hater
yeah, you'd probably want it to function more or less normally as a brake light, but it would be cool to have it doing the back and forth scan whenever the car was parked or something.
 
Picklz

Picklz

SUDO Make me a SAMCH
I think as long as after 'x' seconds it goes to solid and isn't strobing real fast constantly they would leave you alone. Thats whats nice about the premade ones they are already set to go solid after 4-6 seconds usually. It would be nice to have an over-ride switch to turn the scrolling feature off if you wanted.

Hmm would you want the 3rd light to scroll back and forth with the car parked / off? Kind of like a security LED but on the back of the car?
 
dmention7

dmention7

Hater
I dinno, but I think it would be kinda cool to be able to do that. It'd work best if it did it under maybe half voltage so that it was a bit dimmer.
 
Picklz

Picklz

SUDO Make me a SAMCH
Alright so here is A little Electonics / LED Primer

As a couple people have asked for this information I figured I may as well post it up. If I miss anything that should be in here or something is unclear let me know and I'll do some editing :)

This is a Work in Progress, I'll be adding things over the next day or two.

LED - Light Emitting Diode

LED's are a semiconducter of sorts that emit light. Some of their advantages over standard incandesent lights are small size, long life, low power draw and brightness.

Your basic LED has two leads on it or 'legs', an Anode and a Cathode. In simpler terms the Anode is the + and the Cathode is the - as far as current is concerned. Usually one leg of the LED is longer than the other, this is the Anode or + side, also if you look at the LED from the top down, there should be a little flat spot (LED is not completely round) this should corrospond with the Cathode side (-) of the LED (incase the Legs are the same length).

Usually LED's run on anywhere from 2-5volts, some have built in resistors so you can hook them right up to 12 volts. If they don't then you need to put a resistor in-line to reduce the voltage going to the LED. Wherever you order your LED's from should have a data sheet available (or specs posted) that will list what voltage range the LED is capable of running in. Less voltage will equal a dimmer LED, too much and it'll burn out, start on fire, or 'pop' :)


-Resistors-

A Resistor is a electronics component that limits voltage, to figure out what resistor you need for an requires some math and the use of Ohms Law - Resistance = voltage / current....

The formula to figure out what resistor you need for an LED is:
Resistance = (Power Supply Voltage - LED Voltage Drop) / LED Current rating.

So in our case if we had an LED that required 2.0v (fairly common for standard red LED's), and a current rating of 15ma (again, pretty common), you would use the folloing formula:

(12-2)/.015 = ~666

Yeah so thats a creepy number but anyway that's saying you would need a 666ohm resistor or greater, resistors only come in certain values, and those are determined by color codes. The nearest ressitor to what we want would probably be a 680ohm 1/2w resistor. Keep in mind cars generally run in the 13-14v range not a solid 12, so that may need to be figured in when hooking up LED's to a vehicle.

Here is a handy resistance calculator for those afraid of math:
http://led.linear1.org/1led.wiz
 
Picklz

Picklz

SUDO Make me a SAMCH
I agree Jay, that idea hadn't really crossed my mind. Might be better to get it working first then look at a circuit that will apply power to it when the vehicle is off, which shouldn't be all that hard to do.
 
mndsm

mndsm

I'M OFFENDED!
dmention7 said:
I dinno, but I think it would be kinda cool to be able to do that. It'd work best if it did it under maybe half voltage so that it was a bit dimmer.
Click to expand...
Add to that, yeah LED's are low voltage, but my car sits a ton, so even something like that could drain the battery. Any way to have a switch to turn it on/off while parked so we have the option of just shutting it down?
 
mndsm

mndsm

I'M OFFENDED!
The cool part is there is a great little switch blank right by the steering column in which to put the setup for that. I'm liking this more and more. I think as we get closer to building one, we should come up with a final idea as to what exactly we want it to do, and then use whatever knowledge (or lack thereof in my case) to build it to that spec. We seem to have a LOT of different things we all want to see in this, and it could get complicated, QUICK.
 
Picklz

Picklz

SUDO Make me a SAMCH
Alright so far were looking at the following for features:

1) At least 1 scrolling / chasing pattern when you step on the brakes, needs to stop after 5-6 seconds and become solid.

2) If we go with more than 1 pattern, a button or switch will need to be used to switch patterns.

3) Ability to disable scrolling feature completly so the 3rd light works as a standard on / off light

4) Ability to turn on / off a feature to have the 3rd brake light scroll a pattern while the vehicle is shut off, at a lower brightness.


As for #2, might be cool to have some sort of indicator as to what pattern is being displayed (if we go with something that offers more than one), but I dont know how feesable / easy that would be to do.
 
dmention7

dmention7

Hater
What about a second, smaller display that you can locate on your dash like the guy with the eclipse did? It could mirror what the tails are doing
 
Picklz

Picklz

SUDO Make me a SAMCH
hmmm thats possible, not sure where to mount it exactly though, what would be really cool would be to integrate it into the lights that are on the radio, that increase / decrease when you change the volume...but I don't think that's something I really want to tackle, at least not right away.
 
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