924Board.org

[RC]

There has been some interest lately in brighter LED (light emitting diode) dashlights to replace our rather poor standard 5mm wedge lamps. As with most things in life, you generally get what you pay for, and sometimes not even that. High intensity is a vague term and some of the cheaper LEDs are dimmer than the originals.

LED output can be quantified, the unit of measurement is generally mcd (millicandela), or in BS terms 1 thousandth candle power. Therefore a LED of 2000mcd would approximate the luminous intensity of 2 candles, which from experience is brighter than the standard 1.2 watt lamp. This incandescent source however emits its light in the orange/ yellow part of the spectrum, as if you hadn`t noticed!

Since LEDs now come in a variety of colors it may be tempting to experiment here, but after trying a blue one and being very disappointed with the result would not recommend it or the green. Clear white ones are most effective on our dials and do IMHO make a dramatic modern looking improvement.

It is simple to make your own LED style wedge lamps with a few basic parts from your local electronics store. The LED of course, a suitable resistor and a small piece of prototype board with parallel tracks, commonly referred to as veroboard.

Use the standard size 5mm LED which is the same diameter as the wedge lamps. The very high intensity ones have a narrow angle of diffusion, typically 10 to 20 degrees and will give an uneven spread on our instruments with only 2. I recommend the widest angle available, 40 to 50 degrees or greater and at least 2000mcd. I was very satisfied with 5000mcd, and would think that any more would require dimming.

A resistor is required to limit the current at the lower operating voltage of the LED. This is typically over 3 volts for white and significantly less for red ones. It is easy to calculate for any LED available using ohms law, but it is easier still to just ask the guy at the electronics shop. They would get asked this on a daily basis so if the kid cant tell you ask the boss. In practically all cases though a 470 ohm resistor in 1/8 or 1/4 watt is suitable.

The vero board should have a standard hole spacing of 0.1" or 2.5mm. A small piece will make many bases as it is cut with a fine hacksaw or scored and snapped along a line of holes and then filed or ground (watch ya fingers) to 2 strips wide and 3 holes long.



Since a picture really does save a thousand words its easy to see how the wire leads of the LED and resistor are fed through and around the piece of board and then soldered. The remaining leads are merely twisted together , soldered, cut off short and pushed parallel with the resistor. There is ample clearance and rigidity so there should be no need to insulate it.

In practice it makes no difference which way around these two components are connected as it will work in the lamp holder one way and not the other regardless of which way the LED is orientated. The resistor will limit the current and the diode will only flow one way so no damage will occur if polarities are reversed. The shortest lead on the LED is the cathode which will be the ground or negative connection and the longer (anode) lead will be the positive + one. Generally the resistor would be on the anode side but it really doesn`t matter in this case. Only may make it easier to install these little things the correct way. Suggest testing them before installing and mark the ground terminal with a black marking pen.

The hardest part is getting your head and hands up under the dash!





LIGHT UP
Roger

[skemcin]

I've read that LED light illuminate faster than incandescent bulbs to a degree that at 60 mph a LED rear brake light combined with average driver reaction times to light will end up giving the driver behind you a whole extra car length by the time the two of you stop.

One of my next year projects I have been contemplating is converting all my lighting to LED - this How To is helpful in that respect.

Having said that:

• What is your total cost in parts and labor?
  
• I've seen some rear tail light conversions done as well, are you venturing there as well?

Thanks.
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924.org (no time to complete)
9249206346 - 89k – new shifter bushings, belts, running well.
9249206347 - 8k – waiting its resurrection, no power at the fuel pump and fuse #7 blows w/power

[endwrench]

Very nicely explained and pictured! I have actually already converted my dash over to the light sold by the outfit 924RACER posted on the Interior forum. I went with the blue and am happy with them EXCEPT for the speedo. It is better than the OE lights but still not bright enough. I'm gonna research your advice and see if I can remedy this. Thanks,

Todd
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'79 924NA. Rebuilt 9.5:1, MSDS header, Mega Squirt Injection, MJLJ-EDIS Ignition, 1.6L Whipple Charger and Intercooler, 10lbs Boost, 944 Trans, Custom HD Clutch.
"simsport" said....superchargers are better than turbos its official!....

[RC]

LEDs do illuminate faster than incandescent bulbs, about 200ms (0.2 seconds) faster. Bayonet type cluster lights can be bought or made but they may be a problem fitting them through the small holes in our tail lights. A small compact cluster with very high intensity, narrow angle ones could be made or alternatively a single 1 watt may fit.

Your comments Skemcin, reminded me of a circuit designed to activate the brake lights BEFORE the pedal was even pressed. It relied on a fast decrease in Throttle Position Sensor voltage. Unless you have EFI fitted our cars won`t have a TPS but it could be fitted with one. I have this circuit if you are interested and the description is here:
http://www.siliconchip.com.au/cms/A_100992/article.html

Cost of the Leds were Au$ 1.35 about a year ago for 7000mcd, but they have likely become cheaper. They should be available from about 50c up to $2 depending on source. Resistors will be from 1c to 5c each, and the board will be from $2 to $5 at various suppliers and sizes. An average person should take between 1 to 2 hours to do them all. Recall there is 2 in the speedo, tacho and combo while a single one is fitted to the smaller gauges on the console. Also 2 in the heater controls.

The quality of the commercial ones vary substantially. Good if the specs are given since you can compare and if not they are likely quite weak ones. Unlike light globes, brighter ones ARE more expensive.

Blue is a very inefficient color for LEDs and also for the human eye to perceive. It requires about 3 times the power output of a blue light to appear the same intensity as a red one. Although it is a personal choice thing, I was unhappy with the blue on our dials while the white appears brilliant.

Roger

[macBdog]

Awesome article, I'm gonna do this!
_________________
1979 931 with a 350 chev
1973 911E with EFI

[morghen]

...you guys talk about this..post pics and stuff....but i never saw a LED lit 924 dashboard until now.
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Supercharger and EFI kits
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[skemcin]

BTW, have you seen this:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=300158990309
_________________
924.org (no time to complete)
9249206346 - 89k – new shifter bushings, belts, running well.
9249206347 - 8k – waiting its resurrection, no power at the fuel pump and fuse #7 blows w/power

[morghen]

looks like crap if you ask me...
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Supercharger and EFI kits
https://www.the924.com

[skemcin]

[morghen]

well the picture is preety small and low quality but i'd say it sucks because of unequal liteing and the shitty colour wich will burn your eyes....i personaly love the stock dash lights and if i were to search for LEDs to replace the bulbs i would probably get the same colour as factory bulbs provide.
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[pocketscience]

I'm experimenting with colours. Have got blue in my fuel/oil light etc pod - looks pretty nice - not as "in your face" as that one on ebay which is a blessing. The colour is reasonably even considering theres only a couple of LEDs.

I'm trying to get away from the stock off-white/yellow look... of course nice clean white is a different story...


G.
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Whoever said you can't buy happiness forgot about Porsche!
81 924 N/A, GTS lights, Saratoga, interior, headers, Integral cam, EFI (sold)
95 993
69 911

[RC]

Heres a couple of pics of the white ones to give you an idea. Cant take the whole dash as my speedo is still out for repair, but the tacho gives an idea. I`m no professional photographer and these are the best I can do trying to hold the camera still for 8 seconds, so are a little blurred.





The color of the centre console gauges gives a good comparison with the orange look of the stock bulbs still in the heater controls.

Color is a personal choice I know, but IMHO anything looks cleaner and brighter than the stock ones do.

Roger

[924aussie]

You could always try these for night driving

http://www.youtube.com/watch?v=YjTP_T-wR9w
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green 924 .. 1980 rego 924PSH
1998 Mopar Neon ... sick
2003 Challenger / Montery 4WD
1995 Hyundai Scoupe ... sold
1998 Nissan Silvia ... sons back from OS he has taken it
BIG BLOODY MOTORHOME 300zx Sold
1980 Fire truck Sold

[924guy]

some great stuff here. i will be doing something similar, but i think im going to use one larger resistor, instead of using a resistor for each led, and construct a mini plug in harness for each gauge.
this eliminates the need to soldier resistors to each led (which can be tricky since they have to be so close to the bulb) , and you only need one source wire to run several leds. kind of like a fork, the end of the tines are the bulbs, where the tines sprout is the resistor, and the handle is the source wire. its simply a matter of using the correct resistor to reduce the output voltage to meet the needs of the amount of led's in the setup. it becomes a mini harness, and makes led replacement or changing bulb color much easier imo.
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Eric
78 924
82 931 SE "smokey"
99' VehiCross
Y2K Honda Insight
http://www.cardomain.com/id/924Guy
Performance by Pasha

[morghen]

sorry...to bright for my taste...i love the stock orange look.

anyway....what the hell is that guy doing with his hands right before the end of the movie ?!
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