308 Instrument panel lighting upgrade tests

Trying to find the correct post for this update:
I have been spending some time down in the lab experimenting with UV invisible paint and UV leds as a solution to the dim Tachometer face at night. Here is the situation so far. I have a wonderful source for small quantities of invisible paints that work great and have a spectrum of colors including green,blue,red,yellow which is found on the tach face and needles. The leds however present an issue. Around 390-395nm wavelength leds they are visible purple but illuminate the paint well and are safe. The totally invisible invisible UV leds are getting harder to find and I suspect it may be because they present a risk. Everything from cataracts to cancer if exposed long enough. So my thoughts are to mask the led from the line of sight to obscure the purple Led by painting half of it black facing the driver. The exposed face towards the tach face. Two very tiny holes for the led leads will suffice to mount the led inside the tachometer housing. If they are painted flat black on the exposed face from the driver it should hardly be noticed. Next is figuring out what to paint? The needle alone or all the markings as well and try to match the speedo. Below is the visible UV led with the green and red paints.
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Great thread, gentlemen!

I may just have to try an such a conversion on the Merak in the future. Thanks for all the great research and ideas.

Ciao,
George

 

I did the same LED upgrade to my 81 928 which is notorious for having poor illumination. Did the instrument panel as well as lights behind all my various instrument knobs and also all the the footwell lighting. Also used superbrighleds.

It really made a huge difference especially at night and I actually felt like it updated the look of the interior expecially at night. I never ran into any problems with wire temp or fuses.

+1 for a great idea.

 

This is a good find Robert!

About UV emissions if the led are totally covered in black paint, letting the necessary free surface to light the paint it wouldn't be a problem. The light must be spread from the lower part of the tacho and speedo. We will get some UV reflection from the needles, but I think that it will be really dim.

Cheers

 

Doesn't UV light degrade plastics? I seem to recall a warning about that when installing UV lights in my home furnace.

 

You are correct which is why windscreens have uv filters to protect interior plastics from losing the elastic property. However, in this application we are only talking about very brief very low intensity , low energy exposure. Quite different then being under the sun all day long. It is a consideration and perhaps it is wise to bring it to everyone's attention along with the exposure warning. Uv like laser pointers can cause damage to your eyes. Uv can also cause skin issues so use some common sense when working with this stuff.


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I seem to recall sometime ago a post where someone attached a small light strip up inside the gauge binnacle that when lit would shine down on the gauge set. Looked like a simple idea and could not be seen . Just another option. I did the standard bulb upgrade along with jumping out the rheostat which all worked OK . But as we address here the tach lighting was not great. Then again I didn't drive it to much at night so the upgrade was sufficient enough.

 

So received new uv led arrays. 6 emitters on a flat ribbon with adhesive pad on back. The plan is to place in the tach to illuminate the painted pointer. Also got minature dimmer to equalize the brightness with the speedo.


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Nice!
Expecting final test!

 

It's going to have to warm up a bit before I go into my unheated garage.


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This is a great topic and tutorial (How to Dash Lights).

The only thing I would add that when buying your LED look at the (K) to determine the color you wish

Color Temperature:

A measure of the color of a light source relative to a black body at a particular temperature expressed in degrees Kelvin (K). Incandescent lights have a low color temperature (approximately 2800K) and have a red-yellowish tone; daylight has a high color temperature (approximately 6000K) and appears bluish (the most popular fluorescent light, Cool White, is rated at 4100K). Lamps with color temperatures below 5000K tend to be more yellow/red, lamps rated between 5000 and 6000K are viewed as white, while lamps above 6000K tend to have a blue cast.

LED Definitions