Just sharing: My Dash Lighting Project - PeachParts Mercedes-Benz Forum

redbaronph123 · #1 12-28-2004, 08:31 PM

I finally finished it.. after procrastinating for 2 weeks... hehehe..

after countless times looking for the right materials..
after 6 hyper white LEDS
after 2 50 OHM resistors which was later scrapped and replaced with 2 150OHM resistors
after 8 pcs of pin connectors
after soldering the pieces together...
finally did it.

i'm quite happy with the results... though i think i still have to re-adjust the focus of the LEDS to fully light up the dash...

the only problem is.. now it doesnt match my lights up front.. eheh. dunno maybe its just me being OC...i think i need to buy me some hyper white H4 bulbs...

redbaronph123 · #2 12-28-2004, 08:33 PM

and the final result is...

#3 12-28-2004, 08:47 PM

Nice LED project. I'm thinking of doing the same to my SDL since some of the window switches and dash lights are burned out. I'm really not looking forward to ripping everything apart though.

rg2098 · #4 12-28-2004, 11:02 PM

Wow shes bright. You can even read the odometer without turning on the cabin lights.

psdsteve · #5 12-29-2004, 12:13 AM

That is great. Mine are really not very good.

Is there any chance of a wiring diagram as to how you put it all together? Wiring is not my strong point. But I can read and follow directions!!!!

Thanks,

Stephen

JimmyL · #6 12-29-2004, 12:23 AM

I agree with Stephen. Directions for the electrically challenged. Looks excellent, by the way. I see somebody else out there doesn't have a tach.

Jimmy Joe · #7 12-29-2004, 12:46 AM

That is so pretty!
My lights are competely dead, tell more!
How much is that stuff?

#8 12-29-2004, 04:11 AM

If I am not mistake in my view of the picture, you are using two 150 Ohm Resistors (in series?)?

If so...here is a schematic (MS-PAINT!) for you non-electronic types (attached)

The parts would be probably around 5 bucks...perhaps even less.
Radio Shilack would have all these parts....but remember...they aren't very bright down there

If you are going to use 2 150 Ohm resistors (?) then you should make sure to get the same type LED's (Ultra Bright or whatever it is)
These use more current and thus the lesser value of the resistor

Smaller Value Resistors = More current

Too much current and you fry your little silicon based friends

Enjoy

redbaronph123 · #9 12-29-2004, 05:20 AM

the diagram brandon showed is ALMOST right...

i only used the two 150 OHM resistor.. (didnt use the 2 50ohms).. from the diagram.. just use one resistor for the set.. and the other one goes to the other set.
-------------------

3 LEDs on each side of the dash light panel.. with 1 resistor in series with teh 3 LEDs. ..

so you will have two (2) sets of 3 LEDs in series with a resistor on each set.(a set would look like the 3rd picture from the first post.)

i didnt have any problem setting up my dash since the PO already broke the prisms on my dash.. hence i just took them off.. (you may have to find another way to route the wires and the LEDs if yours is still intact and you dont want to ruin the dash) ...from the back...wire these sets to the connector. you'll have to find which of the sides of the connector goes to teh positive.. and which side goes to the negative. LEDs dont light up with the wrong polarity.

i'll try to draw a diagram... though drawing is not one of my forte... ehhehe

#10 12-29-2004, 10:28 AM

At teh very least, the diagram will tell you how to hook the diodes together and what side goes to positive. Just have to play with the resistors. Hope it helped

brandon

8threesd · #11 12-29-2004, 11:07 AM

I found this to be very helpfull for this project:

http://maxmouse007.tripod.com/w126_LEDS.htm

sam

dieseldiehard · #12 03-03-2005, 12:36 PM

I don’t know if anyone has pointed this out before but the value of the resistors as indicated 390K Ohms is wrong. I believe 390 Ohms is the correct value.
“K” indicates thousands, so 390,000 Ohms will only allow .000033 amperes to flow. That will not light the diodes at all.
You need approx. .03 amperes (30 milliamperes) for reasonable brightness.
390 Ohms would provide approx. .032 Amperes considering the voltage drop of the LED. The previous post recommended two 150 Ohm resistors in series - that is better, and shows that the ballpark value of the resistance is in the proper range, ie. NOT K Ohms!!!!
The email on twitty's web page has a wrong Email address, I sent a comment direct but it bounced.

bjcsc · #13 03-03-2005, 01:33 PM

Can they be dimmed?

phidauex · #14 03-03-2005, 02:13 PM

LEDs are not easy to dim.. If you connect a potentiometer to them you can sort-of dim them, but what happens is as the current to the LEDs drops, they do not dim smoothly, they'll 'drop out' one by one, and the color will change as they dim. Its not ideal.

The best way to dim them is to connect them behind some PWM (pulse width modulation) circuitry that turns them on and off 1000 times a second or so. Then the dimmer would control how long it stays on in proportion to how long it stays off.

Like this:

Code:

Fully on: --------_--------_--------_--------_
very dim: -________-________-________-________ 
half on:  -----____-----____-----____-----____

The circuitry is not complex, in the form of a microcontroller (there are some purpose built microcontrollers just for dimming LEDs), but its more complex than just 'wire it up'.

Here is an example of a simple LED dimming circuit: http://www.web-ee.com/Schematics/LED%20Dimmer/LED_Dimmer.htm

peace,
sam

Mister Byrnzoil · #15 03-03-2005, 04:36 PM

Why is it necessary to use a resistor? are the leds that delicate?

I put a red multi LED light in my boat last year I just wired it normally into the 12v system, (maybe it had a resistor built into the plastic case?)

thanks,
Robert

Ps. Looks great BTW! In my jeep I use a flashlight to peer at the last 2 working gauges.