Source For LED Panels (See Design)

Your individual emitters designated as tail or brake: Wrong way to do it. You really want all your emitters to be active in both modes. There are readily available PWM circuits for the dim "tail" mode, and then you just shoot full power to 'em for the bright brake/turn mode.

(The one I'd recommend is the 36-emitter unit P/N M417RP here: ) They're 4" round, and you could simply line 'em up side by side by each, spaced about 3/4" or so away from the inner surface of the car's lenses. Dual-intensity capability built right in, on all emitters, and these guys are BRIGHT. To reduce the appearance of discrete circular areas of light, I'd obtain some diamond-pattern fluorescent ceiling light diffuser material and place a single thickness of it right up against the inner surface of the car's lenses.

If you gotta have rectangular, there is an LED Model 45 from Truck-Lite.

3-13/32" by 5-5/16", P/N 45252R, e.g. (Truck-Lite's own site is down at the moment). These "full-pattern" items cram-packed with emitters are the better way to go, compared to the units which use fewer emitters (5 to 8, typically) with fresnel optics to spread the light.

(Sure, it can be fun to start from scratch using nothing more than perfboard and raw LED emitters, but the optics make a real problem -- they cannot effectively be crafted in your workshop -- and these modules are inexpensive enough that you can pick 'em up, install 'em, and then move on to other things.)

You will need a different turn signal flasher. I recommend an Ideal EL-12C electronic heavy-duty plug-in flasher. Nice loud click, and it won't care that the load has suddenly got a lot lighter. The stock flasher won't work, because it is load-sensitive.

For your next trick:

and ;-)

DS

'Generic PC boards' I think you mean perf. board, just a rectangular PC board, with rows of holes pre-drilled and pads/traces on the back.

You might want to go to a junkyard and see if you can get your hands on a late-model Cadillac taillight assembly, they use LED's just as you are wanting to do. Maybe it will help you with the engineering.

Maybe you can just trim one of these down...

The arrow is already rectangular.

This

has 18 real bright leds in a pattern..

I knew your name would pop up eventually with loads of flawless advice. THANK YOU!

Looking at the websites you provided, I think I can easily adapt some of the products listed to fit my needs. And as far as a diffuser goes, each tail lamp already has a full width clear fresnel (?) lens in there behind the outer red lens. I found that by sticking a single LED flashlight in the center on the lens, it would illuminate the entire lens evenly. Dim, but it was fully lit. So one of these round or rectagular complete LED lamp assemblies in each tail light section would work great. I could get away with four of them I believe, maybe six, or even if I have to use eight, the current draw would still be less than what I'm having with eight 1157's all lit up.

And yep, thermal flasher won't work. I've already switched to an electronic "heavy duty" flasher just for the shear loudness of it. It's a convertible and so there is wind noise... It's nice to be able to hear the flasher ticking.

THANKS AGAIN!

-Steve

Here's the full list....

One issue with many LED replacements is that they generally only have LED's pointing one way, with some also having a few sideways LED's. The main problem is that there may be none pointing toward the rear, which would bounce light off the reflector, giving a broader band of light.

Maybe if you could find a version with a wide distribution of light, along with some of the diffusion techniques posted by others, to get a more incandescent-looking pattern.

Also, if there is such a thing as a 'short' LED version, it may help by keeping the light source further away from the car's lens, giving the light more time to spread. Remember that with an incandescent, the filament is in the middle of the bulb, whereas those LED's look like the light comes right out at the end of a unit almost the same size as an

1157.

Seems like it'd be FAR easier for the novice to use perfboard, at least for the prototype, then if a PCB is designed use one of the online board houses that will professionally make the PCBs, the end product is far nicer for a lot less effort.

And, what is the law?

Seems to me I see a lot of trucks with new LED signal/stop lights, and I can get close enough to see no SAE imprimatur on them.

I have an interest in reducing my motorcycle's current usage - and making myself more visible. LEDs can do it, but I wonder about the legality (since the DOT has taken 30+ years to accept that halogen lights are better than "sealed beams" and) I know LED's can make a big difference in visibility. - seems to me it is just a matter of waiting (should I live that long) untill the LED lobbyists pay more than the incandescent lobbyists. And we, the people, might be able to choose.

I think the bottom line is safety. LED's can do it better than incandescents - but not in a cost competive way (if one happens to be a detroit mogul) so, we have to wait until Detroit allows us this safety feature . . .

Sealed beams were a great improvement over polished silvered iron reflectors - in the 30's- - and so the law was passed - - Halogen lights came along in the 60/70s and could project more usable light where it was needed and not cause glare to oncomming headlights - so the Europeans had them and the US had to wait until General Electric could develop halogen (sealed beam) headlights (that threw more light up in the air than directly ahead). unitl the 80's

When GE got out of the market - auto lighting was more or less for safety. But there's sitll the spector of some nanny lobbyist out there to make us safe (in the corporatetly acceptible way).

"I'm very sure that most places we can't change them without "breaking the law"

Me too.

Then I see celebrities breaking the law. and president's since Nixon, and presidents circumventing the Consitution since I was born and I have to wonder what good is the "rule of law?" It is a matter of what I can get away with - not what is legal.

So how bad can LED lights be?

Just for closure...

Here is a photo of one of the disassembled tail lamp sections.

http://216.110.197.146/taillamp.jpg After poking around with a small LED flashlight and the clear inner fresnel lens, I really think I need to purchase a handful of the round LED lamps you suggested. One of those pre-fabbed tail lamps at the right spot on that lens will make a LOT of light that is evenly dispersed.

Plus, it's all wired and already made to withstand the elements. I can pop them in there, fill the old lamp socket holes with rubber grommets, and be done.

Also, I never realized that the LEDs actually dimmed for tail versus brake lights. I just thought there were just more or less of them illuminated as needed.

So I'll give it a go with the standard round LED lamps you suggest are very bright.

Thanks,

-Steve

Varies by state/province. Some jurisdictions explicitly require that all motor vehicle lighting devices conform to US Federal Motor Vehicle Safety Standard 108 (or, in Canada, Canada Motor Vehicle Safety Standard 108 or 108.1). Other jurisdictions make vague references to (usually outdated and/or inapplicable) SAE standards. Still other jurisdictions contain subjective requirements, e.g. "Every vehicle shall be equipped with two brake lights showing a red light to the rear when the brakes are applied, which shall be clearly visible for a distance of such-and-so many feet".

Well, a few things here: First off, SAE is not a regulatory body. Despite commonly-used packaging language, there is no such thing as "SAE approval". (There's also no such thing as "DOT approval", but that's a different topic for a different day). FMVSS108 and CMVSS108 do not require any particular fiducial markings on vehicle rear lamps. Such markings are optional and are frequently applied by reputable manufacturers of HDV lighting equipment, which implies you're not looking closely enough for the markings and/or you don't know what you're looking for. There are a great many different LED vehicle brake, marker, tail, parking, reversing and directional indicator lamps on the market. Of these, a large proportion are fully compliant with applicable regulations and therefore legal in all states and provinces for use in their intended applications. (The remainder are 3rd-world knockoff crapola-this has been a problem since long before LEDs, and it'll carry on being a problem long after LEDs are obsolete).

LED exterior lights are appearing more slowly on passenger cars, simply due to economic factors. Development and tooling for a good, durable and legally-compliant lighting device design is extremely expensive and quite time consuming. HDVs overwhelmingly use lighting devices made to a dozen or so industry-standard formats (4" round, 7" round, 3" x 5" rectangular and 2" x 7" oblong brake/tail/turn lamps, for instance). Passenger cars, on the other hand, overwhelmingly use model-specific lamps.

How come? What makes you think LEDs are illegal? What spoils the safety compliance of a vehicle is (surprise!) lights that don't produce intensity somewhere between the minimum and maximum prescribed values, through at least the prescribed vertical and horizontal angles, with at least the prescribed minimum ratio between bright and dim intensity modes, with at least the prescribed minimum illuminated area and at least the prescribed minimum resistance to the prescribed types of deterioration. That's a long way of saying homemade brake/tail lights and "LED bulb" retrofits generally don't work well enough to provide adequate safety performance.

It's really not that simple. Some of them are, some of them aren't. Virtually every owner of a '93-'00 Chrysler product who pays any attention at all to headlamp performance pines for the "performance" of the $9 sealed beams on his '60s-'80s cars. And as a concept, sealed-beam construction in standardized form factors makes a great deal of sense for automotive headlamps. The _implementation_ we were stuck with for so many years was poor, but there's nothing about sealed-beam construction, per se, that locks one into poor headlamp performance. There are plenty of bad replaceable-bulb lights, too. There are even bad "Xenon" HID lights. Good lights are better than bad lights; there's too much room in the US headlamp standard for various kinds of bad lights.

Good lights can make a big difference in visibility and conspicuity compared to bad lights. There are some very good LED lights...and a lot of bad ones. And there are some very good bulb-type lights.

This doesn't make any sense. See above; more and more LED-based vehicle lamps hit the road every day with full legal compliance.

You already can.

Er...there were no "iron" headlamp reflectors. Silvered brass, generally. Sometimes silvered steel.

This is all more or less correct, though GE was _last_ to market with DOT-certified halogen sealed beams. Westinghouse, Philips and Sylvania beat them to it by a fairly long margin. GE kept insisting and insisting that halogen technology was "unnecessary" on automobiles, and that its use would create more problems than it would solve. This was probably due more to GE's having recently-at-the-time sunk a great deal of money into retooling their tungsten sealed beam production facilities. Ironically, GE was first to market with a halogen sealed beam in North America. In the early 1970s, GE Canada produced a "Quartzline" 5-3/4" halogen sealed beam high beam, called Q4001, and marketed it in Canada. It complied with European photometric requirements and therefore was legal in Canada, but was "too intense" for the US' unrealistically low high beam intensity limits and so was not sold in the US.

GE is very much still in the market. And auto lighting has for a very long time been as much about politics, economics and non-tariff trade barriers as about safety.

Very bad. Just as bad as other kinds of bad lights, if they're not designed and built properly.

DS

I have a 66 Mustang 2+2 that has LED lights from a company called Mustang Project

.You can contact them and see if they have a universal led kit for othercars.

BTW, you are correct about using the original wiring harness for high current devices. What I do is use my original switches and wiring just as "signal" sources, and have them feed high current automobile quality relays. My headlights, fuel pump (fuel injected 5.0), electric fan, fog lights etc. are fed by a new heavy (and fused) 12v bus.

John

There's nothing wrong with the sealed beam construction itself, but the classic DOT headlamps *suck*. Installing quality OEM E-code headlamps on my European car was the best thing I ever did to it. People who ride with me often comment at how good the headlights are and they're usually shocked when I flip on the high beams. The original sealed beams were downright dangerous, I was overdriving my headlights going 5 under the speed limit on a dark highway, yet they still produced more glare to oncoming traffic than what I have now.

a task like this would be good way to gain skills.

start with some perfboard (circuit board with lits of holes and no cobnecteions made between them) figure out your LED layout stick the leds in then join them up by the bits that stick out the back

by the time you've done the few thousand solder joins your design wants you'll be an expert. :)

depends what the law says: it might just say "clearly visible" from such an angle and distance... still that could have a bearing on the best choice of LED.

Bye. Jasen

Yep, many of them do. I have a few interesting E-code sealed beams that produce very well-focued beam patterns. They're little more than historical/technical curiosities by dint of being an uncommon design; sealed-beam headlamp construction really never caught on enduringly outside North America. That said, European regulations are now being written for the optional installation of sealed-beam *fog* lamps, for some strange reason.

Got a well-stocked public library near you? Go find Car & Driver, March

1979. Start reading on page 93, and don't quit til page 111. It is sad how much of it's still completely true.

DS

Personally, i would try diffusing the existing replacements by roughening the surface and placing a thin layer of milky plastic in front of the LED's. A PCB full of LED's would look like a bunch of dots too.

And you came up with this how? legal requirements state otherwise.

Just look at them, legal or not, they're dangerously dim, at least the ones I've seen in use so far.