Bronco Forum - Full Size Ford Bronco Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
13,893 Posts
Discussion Starter #1
Does anyone know how to wire individual LED lights, to a small circuit board, similar to this one? http://www.radioshack.com/product.asp?catalog_name=CTLG&category_name=CTLG_011_002_002_000&product_id=276-148

I've been trying to find any site that shows how to wire it, so the running lights, and brake/blinkers work like they do on our Broncos, rather than having separate sets of lights for each task. I don't know if it needs any diodes, resistors, relays, or even how to finish the pigtails

Anyone know where I can find this kind of information? BTW, this isn't for a Bronco in particular, I'm just wanting to know how to wire the individual lights, so I can different designs and shapes for the taillights

edit - just found some of my answer, now to find out how to wire it so it's "runing" and "braking"
 

·
Registered
Joined
·
57 Posts
Are you saying by "running" and "braking" you would like them to get dim/bright respectively? If so, simply run two wires into one of the sides (positive and negative are irrelevant on LEDs) and connect a say...2.2k resister inline to the wire running from your parking lamps and a straight shot from the brake light wire to the LED. Try and pick up several resistors though and see what will be bright enough for the parking lamps. Good luck!
 

·
Registered
Joined
·
73 Posts
The most important factor in LED design is the current running through the LED itself. A rule of thumb that I learned in college was that you typically want about 13 mA of current for a red LED, this vary's a lot in the real world though...the datasheets from the LED supplier will tell you how much current the particular LED you are dealing with can handle. Polarity is critical on a LED, after all, it's just a diode that happens to emit light. Hook it up backwards, and no current will flow. Here's a decent link showing how to hook up and design the resistance value rather than guess-and-check: Led Link

In a 12 volt system:
R = V/I
R = 11.3/13mA <--11.3 Volts because there is a .7 volt drop across an LED
R = 892 ohms <-- for 1 led

If you hook multiple LEDs in series, you can use fewer resistors, but you'll need to account for the extra voltage drops.

R = 10.6/.013 <--For 2 LEDs in series, there's 1.4 volt drop for both
R = 815 ohms

Theres gonna be a limit to how many you can put in series, eventually the sum of the voltage drops will mean you won't be able to get enough current to turn the LED on. The standard .7V drop is a rule of thumb also, this will vary from LED to LED, but is a good value to design with.
 

·
Registered
Joined
·
13,893 Posts
Discussion Starter #5
Thanks guys, I think this answers all my questions. I have been hoping I can find LEDs that I can just wire and go, but I've also been wondering how to wire them so my running and brake lights work, with the same LED, rather than having to use the wire for the running lights just for the running LEDs and the brake wire for the brake lights just for the brake LEDs. Which brings me to this question - do the running lights run at a full 12V, or are they at a lowre value, like 7-8V? Because if that's how it works, then I can run with BlackS's suggestion, and use the same lights for both duties, rather than having separate circuits, which is what I'm hoping to avoid.

And thanks to arcane for the link, I was trying to remember that site, but couldn't. Hopefully, I can wire a set of taillights for the Bronco, as a test, and see how it goes
 

·
Registered
Joined
·
73 Posts
You can still use the same LEDs for taillight/brake operation, but you'd have to design a slightly fancier circuit to do it. By the time you were done it would probably be cheaper/easier to just buy them.

http://www.superbrightleds.com/1157.htm
 

·
Registered
Joined
·
13,893 Posts
Discussion Starter #7
I agree, it probably would be easier, and cheaper, to buy the LED bulbs, but I like to do things myself, and be unique about it. So I don't have a problem with the wiring, it's just fingering out how to do it right, but I'm definitely going to keep that link in mind, JIC I change my mind, and get cheap about it
 

·
Registered
Joined
·
528 Posts
Running lights are not at a lower voltage. The std bulb has two filaments, each of different wattages, hence different brightnesses.
 

·
Registered
Joined
·
13,893 Posts
Discussion Starter #10
That's what I was trying to finger out - how to run the LEDs as both running lights, and brake/turn lights.. haven't found the answer yet
 

·
FSB Pimpster & Recruiter
Joined
·
5,716 Posts
Dave, Grote has the LED lights for both turn and stoplight....They are made to fit the square grommets like on the back of an 18 wheeler and such....

They may even make 'em in a round model....

Allcruisen :imp :usa
 

·
Registered
Joined
·
13,893 Posts
Discussion Starter #12
Yeha, I know that, but I don't want just what you can buy anywhere, I want mine to have a completely different shape to them, that's why I'm making a bit of a big deal about this
 

·
Still Learnin!
Joined
·
504 Posts
The easy way to do it would be alternating rings. take the led's and start at one corner go around the boards parameter then work inward. Now on every other row jump over one row with a jumper. (note this would have to be done on a non traced board or a board you traced yourself) this way your running lights would cover the full length of that board, but every other row on top would be brakes, and every other row on the bottom would be turn signals. it's hard to explain what I’m trying to say but I think you get the idea. The voltage would be the same but the running lights would have a lesser value resister than the turn or brake lights, but the turn and brake lights would have the same number of led's so there resister value would be the same. as for backup lights get another board with jus one segment on it and fill it.
 

·
Registered
Joined
·
73 Posts
This is a quick idea, I don't have time to prototype it, but the idea should work:


This way you run the same LEDs, only with a different resistance value for the brake lights and the running lights. D1 and D2 keep the brake lights from back-powering the running light circuit and vice versa. In the case where both are on (running lights on, hit the brakes), the voltage at D1 will be greater than that at D2, so the lights will remain in the brighter state. You'll need to expand to more than one LED :toothless There's probably something I'm missing right now, but it's an inexpensive circuit that is worth checking out.
 

·
Registered
Joined
·
13,893 Posts
Discussion Starter #15
Hwy - I think I understand what you're saying, but I'm still wanting to use the same LED for 'double duty'. And I will be taking care of the backup light just as you mentioned - on it's own board

arcane - thanks bud, that split is where I was getting confused at. I knew I would need at least one diode and one resistor in there, but I couldn't figure out if I needed more, and/or where they went. I'm going to see how soon I can gather up the parts, and give this a shot, to make sure it works like it should


Thanks again guys, and if there's anything that might have been missed, then by all means, post up
 

·
Still Learnin!
Joined
·
504 Posts
Yay take lots of pics when you make em. And a detailed write up. I like the idea and just might copy it (if ya don't mind) or have ya make me a set.
 

·
Registered
Joined
·
246 Posts
I think your going to wind up with a very complicated circiut. LEDs don't dim with lower voltage they just turn off. If the LED take 1.2V to light then it will only use 1.2V to light if try to run .9V to get a dim light you get nothing. Polarity counts too. Your best bet would be something like this:

b = brake t = parking

bbbbbbbb
bbbbbbbb
bbbbbbbb
bbbbbbbb

btbtbtbtbt
tbtbtbtbtb
btbtbtbtbt
tbtbtbtbtb

this is realy crude but might help give you some clue. If you alternate the light function and space the parking LEDs out it might appear dim. Then your brakes will alternate with the turn signal.
 
1 - 17 of 17 Posts
Top