Custom LED dome lights

[Bitsyncmaster]

I've been wanting to do a little project for LED dome lights as long as I've owned my car. Well on my last electronic parts order, I bought some SMT white LEDs. I was going to mount them on a circuit board and see how they looked but looking at my dome light units they have cracks in the housing. I ordered some new ones from DMCH and was wondering if the new ones lens is made the same as the OEM units.

Would like to play with the old ones testing if I should mount the LEDs all flat or maybe have rows pointing at an angle.

[content22207]

New lens is ~same width, but you have much less length to work with.

Inside width (tapered towards the lens face): .078" to .068" old, .079" to .071" new.
Working length: 2.73" old, 2.18" new.

You really need to buy one and use it for test fitting.

This is what I rigged up for Farrar and myself (and a Houston bulb for comparison -- 5050 SMD's, with 3 circuits per chip, are *MUCH* brighter):
5102 5103 5104 5105 5106

Bill Robertson
#5939

[Bitsyncmaster]

Thanks for that data Bill. Do the new switches still have the function of center off, forward on and rearward auto?

I'm planning on mounting as many LEDs as I can fit. We will need to have a contest at DCS-12 to see whose are brightest.:tongue_stick:

[content22207]

5112

If you look closely, you will notice I have modified my front courtesy light to shine straight down in door mode (you can still flip it forward too, but that is pretty pointless since it then shines on the hood). Flip it back towards the interior of the car for map light mode.

Bill Robertson
#5939

[Bitsyncmaster]

I cut a board to fit the old unit. If I wanted to fill the board, I could place 168 LEDs on it. But at almost a buck each I would go broke making two. I think it will have 50 LEDs consisting of 25 strings of 2 LEDs at 15 ma. each. Total power would be 0.375 amps or a little more than half of the 7 watt incandescent. If it's to bright I will drop the current in each string. The LEDs are rated for 20 ma. but I think it will be to bright.

[content22207]

I bought a couple of Made in China SMD festoon bulbs off eBay, cut the ends off, soldered them together, then rigged up a festoon adapter from a piece of wooden dowel. Total cost was $3 or $4.

Bill Robertson
#5939

[Bitsyncmaster]

Did some testing with these LEDs. If I were making a PCB I would use strings of three LEDs on each constant current regulator. But since I'm hand wiring this board I staying with strings of two. I also will do a test in the car with a total of 24 LEDs. I found these are very bright even running 12.6 ma. in each string.

I'm always looking at new data sheets when new LEDs become available. These units I bought are the best (efficiency) I've found so far.

[Bitsyncmaster]

Not that anyone else is going to build a custom LED board with components, but here are some photos to give some ideas to someone that may.

I powered it up and it illuminates a very large area very nicely. I will probably mount this first board in my old dome light just to see the results before I play with the new dome light units.

[Ozzie]

Your soldering skills, with these micro tiny components, still amazes me.
Very cool.

[dvonk]

Your soldering skills, with these micro tiny components, still amazes me.
Very cool.

+1. awesome!

[DMC5180]

Your soldering skills, with these micro tiny components, still amazes me.
Very cool.

Yeah, tell me about it. I've gotta learn how to do that one of these days.

I'd love to see the tools used for this stuff. Perhaps a short video demonstration.

I'd like to build something like that for the rear license plate lights. I have LED festoons in there now. But the Frame insert blocks off a fair amount of the light because of the Position of the Festoon contacts. The light needs to be concentrated in the rear half of the lens. A Board could fill that area easily.

[content22207]

Don't buy bulbs with hemispherical LED's -- you're just wasting your money.

5050 SMD's have 3 circuits per element. A 6 element SMD bulb actually has 18 circuits. That is why they are so much brighter.

This is what my license plate looks like with 12 5050 SMD's (two 6 element bulbs -- 36 circuits):
5227

Bill Robertson
#5939

[DMC5180]

The LED's I have are a few years old Technology now. I know there are better options out there today. Bill, did you build those rear lights also?

[Bitsyncmaster]

Don't buy bulbs with hemispherical LED's -- you're just wasting your money.

There is a place when you do want those. My third brake light is one use. But when your trying to illuminate something close you a need wide angle light source. The ones I used for the dome are 110 degree in a 1208 package. These are pretty large for SMT and all you need is a good temp controlled iron with a small tip, small dia. solder, tweezers and a board clamp is nice.

[Ozzie]

Don't buy bulbs with hemispherical LED's -- you're just wasting your money.

"Nonsense!"
:neener::elmo1::neener:

My SMD LED taillights work just great, thanks.
Off the shelf technology, in a blister pack, no less, plenty bright - even in the daylight.
http://dmctalk.org/attachment.php?attachmentid=2345&d=1309921761

[content22207]

Ummm, SMD's are not hemispherical....

My tail light bulbs are SMD too (brake function):
5228

This is what they look light during the day:
52305229

Your license plate bulbs do look a little dim.

Bill Robertson
#5939

[Ozzie]

Your license plate bulbs look a little dim.

Running warm white festoon LED in there (SMDs, btw), plenty bright, but got darkened in the picture with the Photoshop swirl edit.

Just a preference note: I lean towards warm white LEDs, over typical LED colors. That's what I use on the plates, engine bay and dome light housings. To me that color gives the car a more 80's retro look, rather than the typical cold-ish, slight blue, color of the typical LEDs.

FYI:
Last year for my work, I got to attend a 2 day conference on LED technology, with many presentation from large manufacturers of LEDs. It was very interesting to hear the progress and the technical aspects of LEDs. On color: when they go for pure white (or as much as possible), they bin the resulting batches just like Intel does with frequency capabilities of CPUs. OEMs can buy the bins by color, where the whitest ones are the priciest. Typically the blue ones are the most plentiful from a batch sort, and thus are sold very cheap, which explains why you see them so much.

[content22207]

My license plate bulbs are 7000 Kelvin, thank you very much -- very un-blue.

Bill Robertson
#5939

[Ozzie]

My license plate bulbs are 7000 Kelvin, thank you very much -- very un-blue.

Bill Robertson
#5939


"Ummm" that would be, very blue-ish white.
...and they look blue-ish on my screen, but hey, there's nothing wrong with that look, color preferences are subjective.

Most alternative consumer lighting that tries to replace incandescent are labeled as "warm white", which is about 2700 K.

Here is a reference (http://en.wikipedia.org/wiki/Color_temperature):
"Color temperatures over 5,000K are called cool colors (blueish white), while lower color temperatures (2,700–3,000 K) are called warm colors (yellowish white through red)."

[content22207]

"Warm white" SMD's produce about 10% fewer lumens than "cool white" -- something owners looking for maximum output should keep in mind.

Bill Robertson
#5939

[Ozzie]

"Warm white" LED's produce about 10% fewer lumens than "cool white."

Bill Robertson
#5939

Good for you.
So you do have blue-sh LEDs, then? "7000K" ones?

[content22207]

With the exception of colored lenses, my entire car is illuminated with the same color frequency as fluorescent tubes -- 6500 to 7000 Kelvin:
5231

Bill Robertson
#5939

[Ozzie]

With the exception of colored lenses, my entire car is illuminated with the same color frequency as fluorescent tubes -- 6500 to 7000 Kelvin:
5231

Bill Robertson
#5939

Not a thing wrong with that.

Edit:
Sorry, had to walk away. Was going to add: "Just not for me. I work in fluorescent for 50 hours a week. That's enough for me. LOL."

[Bitsyncmaster]

There are lots of ratings on LEDs referencing how good they are. But mostly we want to know how bright they illuminate something else (like dome lights) or how bright they look as indicators (looking directly at the LED.

You can also get SMD (surface mount device) sometimes called SMT (surface mount technology) with or without a lens. The lens can be made for narrow beams or wide beams. Some use no lens for their wide beam.

[Ozzie]

Here's a question I've wondered about:

What color (if any) LED would you put behind a red OR amber lens?
Would you put a red LED behind a red lens, or a white(ish) LED behind a red lens?
Same question for amber.

I haven't experimented, I am running red SMD LEDs on my taillights, and amber LEDs on my indicators. That combination works well, but I wonder what the difference would be with white(ish) ones? Especially since the incandescent bulb that came out was non colored.

Wondering what combinations and results you guys have gotten.

[content22207]

LED's produce a very narrow spectrum of light. A white LED behind a colored lens will look dull because it doesn't produce any of the color of that lens.

Ever notice how hard it is to distinguish colors with an LED flashlight? You'd get the same effect from your lens.

Bill Robertson
#5939

[Ozzie]

LED's produce a very narrow spectrum of light. A white LED behind a colored lens will look dull because it doesn't produce any of the color of that lens.

Ever notice how hard it is to distinguish colors with an LED flashlight? You'd get the same effect from your lens.



So then:
General rule of thumb is to put a same colored LED as the lens that will be in front of it.

That's what I've done and it seems to work well, but was wondering if white(ish) LEDs were any better.

[content22207]

Left lens, white LED's (140 lumens). Right lens, red LED's (15 lumens).

5232

Bill Robertson
#5939

[Ozzie]

Left lens, white LED's (140 lumens). Right lens, red LED's (15 lumens).

5232

Bill Robertson
#5939

Nice!
A great example. ...shouldn't the lumens be higher on the right? Typo?

[content22207]

Those are 1157 bulbs: 15 lumens tail, 90 lumens brake (according to Superbright).

I bought the white LED bulbs for the backup lenses, but discovered that they were less than optimal in that function (incandescents throw much more usable light, especially if you solder across the terminals of an 1157 bulb, transforming it into a dual element 1156).

I also use incandescents in my turn signals because LED's can't pass the side light voltage necessary for the 4 way flasher mod (at least not with incandescents in the side lights -- I haven't tried the 4 way flasher mod with LED's in all sockets).

Bill Robertson
#5939

[Bitsyncmaster]

A good white LED will produce about 7 times the light of an incandescent with the same amount of power used in both. With an incandescent all the input power goes into the bulb. With and LED you need to account for the regulator (resistor or other current limiter). With my dome light, each LED drops about 3 volts so with the string of two the LED voltage is 6 volts and the regulator is the rest. That's why I should have used strings of three. With my strings of two, LED power is 0.9 watts where as the incandescent is 7 watts.

But half the light power of the incandescent is directed at the roof so that gets lost as heat. So the result of my dome light LED is more illumination than the incandescent. Yes I could have gone way overboard and used more LEDs and higher currents and get way more light.

Now the same goes for using a colored lens. The lens will filter (only pass that color) of light so the rest of the light gets absorbed as heat. Here is where you can get away with a lot less LED power since the incandescent is only passing a small amount of it's power with that filter. The colored LED will be passing all of it's power since the filter is matched to the LED.

[content22207]

Incandescent light radiated towards the side and rear is not lost in the front and tail light fixtures because it is reflected back forward by the parabolic reflectors.

LED's are more efficient in the red and amber sockets because they do not produce wavelengths filtered out by the colored lenses, but LED's can not compete with incandescents in the backup socket. A typical 1156 incandescent bulb produces more lumens than an LED bulb (~400 lumens versus ~200 max LED lumens -- some LED bulbs produce less than 100), and an incandescent bulb produces more of the visible light spectrum (there is no colored lens in the backup socket to filter it out).

If the dome light fixtures had parabolic reflectors the same would apply to them.

A good rule of thumb is: use incandescents to see, use LED's to be seen. That is why modern police cars have LED's in the flashing blue lights, but halogen bulbs in the alley and spot lights.

Here's a fun experiment: use only an LED flashlight to look through your closet. Colors and textures will be much harder to distinguish than they are with an incandescent flashlight.

Bill Robertson
#5939

I used LED's in my courtesy light package for several reasons:
- I think the concentrated upper wavelength looks very contemporary (like fluorescent lights)
- Incandescent bulbs often melt plastic lenses
- Some areas, such as the door edges, can only be illuminated with LED's

Notice, however, that I had to use nearly 170 LED elements (more than 500 circuits) spread throughout the car, and I still can't use them to distinguish black from blue.

Power consumption was not a major concern for me, but heat against the lenses was.

Bill Robertson
#5939

[Farrar]

Any progress on the new dome light fixture? Mine (Houston unit) has broken and I would rather replace it with something better than try to glue NOS plastic back together.

Farrar

[Bitsyncmaster]

Any progress on the new dome light fixture? Mine (Houston unit) has broken and I would rather replace it with something better than try to glue NOS plastic back together.

Farrar

Still waiting on shipment of my new fixtures. DMCH was out of stock but they estimated a few weeks.

[Farrar]

Order your own and save yourself some waiting time. It's Hella part number 1628874. Crosses over from 1989 Porsche 911 (interior light).

Farrar

[Bitsyncmaster]

I got the new dome light fixtures. Looks like you can not have all three functions (auto, off and on). So it will be off in center and auto forward or backward. I have to agree with Bill that forward is kind of useless anyway.

The switches really make a solid connection (more spring pressure) which I like.

Now to build up a couple more LED boards.

[Bitsyncmaster]

I've decided to wire my new dome lights so the center is the auto function and forward and back are manually on. Then I will put one of those table lamp push buttons (push on, push off) onto the single purple/white coming off the door diode. With that switch, I can turn the dome lights off if I set my dome unit into parade mode. The switch will just remain at the diode by the driver foot since I rarely need to use it.

Wiring it this way keeps the new dome light pointing down for normal operation. The new dome lights from DMCH has the clear lens flush with the black bezel in the center position. It also does not need to make the mechanical switch contact for normal operation.

[Farrar]

Dave, interesting -- I actually thought of adding the "courtesy lights on" function via an unused rocker switch (I have two of these instead of dummy switches on the console).

Farrar

[tyb323]

What's the largest size smd cluster I can fit in there? I'm looking at these: http://www.superbrightleds.com/cgi-bin/store/index.cgi?action=DispPage&Page2Disp=%2Fspecs%2Ffestoonhp_4210-xHPx.htm

[Bitsyncmaster]

What's the largest size smd cluster I can fit in there? I'm looking at these: http://www.superbrightleds.com/cgi-bin/store/index.cgi?action=DispPage&Page2Disp=%2Fspecs%2Ffestoonhp_4210-xHPx.htm

You could go wild with it laying out your own board. You can get LED chips that are real small and there is quite a bit of room in it. I ended up using 26 LED chips that are the best available right now. I think each one cost me about $1.30 each. I will measure the board size I used when I get home.

[tyb323]

You could go wild with it laying out your own board. You can get LED chips that are real small and there is quite a bit of room in it. I ended up using 26 LED chips that are the best available right now. I think each one cost me about $1.30 each. I will measure the board size I used when I get home.

I'm not that adventurous! Not very good with electrical stuff. That being said, I have found out the size I need to get is 3710-xHP3. Will the wider array there fit (the one with 6?) or only the smaller one with 3?

[Bitsyncmaster]

My LED board is 0.80" x 2.75" and it hot glued on the clear lens. This is about the largest area you could fit. I don't use an off the self replacement bulb so you could use my dimensions to estimate what you can fit.

[Farrar]

If you're using the Hella fixture that I (and Dave?) use, then I am pretty sure a 6-SMD module will fit, but I am not sure it will pivot properly. I can try this when I get home tonight and post some pictures if you're curious. (I'm curious as well as to how this would work out, in case the Bill Robertson fixture ever breaks somehow. So this is a good excuse for me to try this, anyway.)

Farrar

[tyb323]

I ordered the 6 bulb fixture. If it doesn't fit, then I will return, order the three. I think it should though. Will keep you all posted

[Farrar]

I ordered the 6 bulb fixture.

Oops, you ordered before I could take pictures. Oh, well -- I tried the 12 and it didn't fit; I think the 6 will.

Farrar

[Bitsyncmaster]

Got my new HELLA fixtures today. Looks like I will need to make another set of LED boards. The lens on these is wider but has shorter inside size since there are masive pivits of the lens. I like how soldid these are built. The pivit pins are what hold them into the car. They look like they are the same as OEM for fitting the existing hole.

These are a longer bulb than the new ones from DMCH.

[Farrar]

Dave, are you planning on using 4 "strings" of 6 LEDs to make the voltage drop good for our 12-14v systems or will you be using resistors?

I think you will be happy with the way the Hella fixture "spreads" the light.

Farrar

[Bitsyncmaster]

Dave, are you planning on using 4 "strings" of 6 LEDs to make the voltage drop good for our 12-14v systems or will you be using resistors?

I think you will be happy with the way the Hella fixture "spreads" the light.

Farrar

White LEDs drop 3 to 4 volts each so the best you can get in a string is 3 devices. You have to have a current limiting circuit in LEDs or they will not last very long. I use a constant current circuit (LM317) for my designs. That keeps the same current no mater if the engine is on or off. You can use a resistor which lets the current change more so when the strings drop is close to the voltage. So resistors would be fine with one or two LEDs in the string but not so good with 3.

[Farrar]

White LEDs drop 3 to 4 volts each so the best you can get in a string is 3 devices.

Oops, I was thinking of the little red LEDs I get at Radio Shack.

Farrar

[Bitsyncmaster]

Did a little work today deciding what to do with the dome lights. I think the best bet is the HELLA unit because it's the proper size (have not fitted it yet but Farrar did) and built pretty solid. The lens is larger because the benzel is narrower. The lens can not be removed but the unit is open on the back side so I can install my board.

I experimented with a new LED board design. I will end up using strings of 3 LEDs and my constant current drivers. I built up one string and it holds constant current down to 12.1 volts so it will have the same current with the engine off or on. My white leds run 2.85 to 3.05 volts each at 12.5 ma. I also put a diode in each string. I've found blue or white LEDs don't like reverse currents. Will probably end up with 30 to 40 LEDs total.

[Bitsyncmaster]

Here is what I came up with for the HELLA LEDs. Ended up with 10 strings of three LEDs. But as I was testing the com pleated board, I noticed quite an improvement in what it illuminates as the string current (12.5 ma) is increased. So I'm going to do a little more testing when I start the second unit. The LEDs are rated for 20 ma. max so I really don't like to run the maximum current so I get long life (never burned out). But I may adjust my current regulators for somewhere between 15 and 18 ma. depending on what I see with more bench testing.

[Farrar]

Dave, I continue to be amazed by your soldering skills. Excellent work, man!

Farrar

[Bitsyncmaster]

I finished one light. Ended up setting the string current to 16.7 ma. So each dome light will draw 167 ma. Each door light draws 30 ma. The engine and trunk are off the self 6 LED bulbs. So the only one left to LED is the glove box. I think I will drop my curtesy light fuse down to a 3 amp.

I will test if this new dome light is to bright before I modify the first one to the higher current.

[congerz83]

I need some help here. I have one of these domelights in the front...
http://www.ebay.com/itm/DeLorean-DMC-12-81-82-83-Dome-Courtesy-Light-/110673817355?pt=Motors_Car_Truck_Parts_Accessories&fits=Make%3ADeLorean&vxp=mtr&hash=item19c4ac6f0b
With the stock in the back. Does anyone else have this "3rd-Party" updated version? I'm not sure how the wires are supposed to go. The prongs are different from the factory dome-light. I put the new SMD festoon bulbs in. They looked awesome, but would not turn off when I closed the door.

[Farrar]

I am not familiar with that fixture but the black wire is "always ground" and the purple/white wire is "switched ground" (from the door plunger switches). The remaining wire you know what that is. ;)

Have an extra 10A fuse handy just in case. ;)

Farrar

[Ron]

It says it comes with a wiring diagram..

Look at the connections closely and you will see that one end of the bulb goes to two connections and the other only goes to one, which gets the pink wire. The Black and Pink-White can be swapped to change which position it aims....

The delay module is probably the problem, read this-
http://dmctalk.org/showthread.php?1631-Door-Lights&p=20184&viewfull=1#post20184

[congerz83]

If you still have the OEM dome light delay, that will keep LED dome lights glowing. My new dome light delay can also do that with some LEDs which you can fix with a resistor or just ignore it because the current is just 200 ua.

So remove the OEM dome light delay with LEDs in the dome lights.

I wouldn't have to replace this with something? Jumper? Just simply pull it?

[Farrar]

Just pull it. You won't get a delay -- the lights will simply shut off when you close the door.

Farrar

[Ron]

Just pull it. You won't get a delay -- the lights will simply shut off when you close the door.

FarrarNa...stocking stuffer!!!

[Bitsyncmaster]

Project done except for getting the rear dome light to hold in tighter. The front one snaps in great but the rear one must have a larger cutout or the cutout has been damaged through the years. I do recommend these HELLA dome light fixtures. They are built good, have a solid switch and have all three original functions (auto, off and on). No wire modifications required.

When it gets dark, I will try to get some photos posted. But already I see the back one lights up the area so much better.

[Bitsyncmaster]

Here are the photos taken in total darkness (no flash). It's hard to judge LED photos but these came out pretty close to what I see in person.

Please excuse the mess in the back photo.

[sean]

Here are the photos taken in total darkness

Very nice!

[Farrar]

Damn impressive, Dave! I think I need one of those modules for my front dome light. Can I send the fixture to you with a check or something? :)

Farrar

[congerz83]

I pulled the module and everything worked out fine. I ordered another one of my eBay dome-fixtures because the lens is broken in the rear and does not lock in properly.

[tyb323]

Oops, you ordered before I could take pictures. Oh, well -- I tried the 12 and it didn't fit; I think the 6 will.

Farrar

Well in terms of width, it was an ok fit, but the one I ordered wasn't nearly long enough. What size do I have to order? I believe I ordered 37mm

[Farrar]

I ordered 42mm units.

Farrar

[Bitsyncmaster]

I ordered 42mm units.

Farrar

The HELLA unit has a longer bulb (also 10 watts) then the other one I got from DMCH. So it's all going to depend on which dome light fixture you have.

[tyb323]

The HELLA unit has a longer bulb (also 10 watts) then the other one I got from DMCH. So it's all going to depend on which dome light fixture you have.

I have the later one, so I guess I gotta order the 42!!!

[tyb323]

42 is in the car. Had to bend the contacts a bit closer to hold it tight but the difference in lighting from houston's leds is spectacular. Easily 10x the light. The one dome light now illuminates most of the cockpit and combined with my footwell lighting, the cabin is very well lit at night

[Spittybug]

42? Can you post a link to what you have put in? This thread is getting tougher to follow with the numbers, custom builds, lengths...etc... Thanks.

[DMC5180]

Sounds like SMD's are the way to go these days. A vast improvement over the LED's of a few years ago.

[QuadcityDMC]

Anyone have a link to these new dome ligths?

[Ozzie]

Anyone have a link to these new dome ligths?

Google Search Link (https://www.google.com/search?rlz=1C1GGGE_enUS407US407&gcx=c&ix=c1&sourceid=chrome&ie=UTF-8&q=hella+W0133-1628874#q=hella+W0133-1628874&hl=en&rlz=1C1GGGE_enUS407US407&prmd=imvns&source=lnms&tbm=shop&ei=1L_JTvDwH9CBtgf3uJGFDA&sa=X&oi=mode_link&ct=mode&cd=6&ved=0CB8Q_AUoBQ&bav=on.2,or.r_gc.r_pw.r_cp.,cf.osb&fp=941f1d54784d999&biw=1144&bih=931)

[tyb323]

42? Can you post a link to what you have put in? This thread is getting tougher to follow with the numbers, custom builds, lengths...etc... Thanks.

http://www.superbrightleds.com/cgi-bin/store/index.cgi?action=DispPage&Page2Disp=%2Fspecs%2Ffestoonhp_4210-xHPx.htm

I used the 6 SMD unit, called 4210-xHP6 in cool white

[Farrar]

Note that the Google Search Link provided above contains both correct units and incorrect ones.

It should be obvious which one is correct, though.

Farrar