12 Volt cockpit lighting

[Westozy]

Hi all,

Soon I am going to start the last phase of my simbuild which will be the panel backlighting, wash lighting and also general cockpit lighting. I have a near new 13.2 volt regulated DC power supply and intend to use low wattage auto bulbs. I want to fit dimmers to the MIP panels that work and was wondering if anyone has a circuit diagram on how to build 12v DC dimmers. I have achieved pretty good backlighting on my overhead panel with a few 12v festoon globes but don't know how to make them dimmable. Is this a good way to go or should I be doing it differently? Electrics/electronics are not my field and I would appreciate some good advice.

Cheers in advance, Gwyn

[Tim]

Why not purchase the dash dimmers found in cars? I should think those would work in the sim like they do in a car.

Not sure about new vehicles but I would suspect older vehicles just used a variable resister?

[Tim]

Appears to be many Google hits on "dash light dimmer" or similar.

You may want to consider white LEDs vs incandescent bulbs. LEDs are very low wattage vs 12v bulbs. The incandescent bulbs will get warm to hot also. But, I'm not sure you can dim an LED.

Here is a good site for explaining how to wire LEDs. A current limiting resister is very important.

http://www.theledlight.com/ledcircuits.html

[magicaldr]

But, I'm not sure you can dim an LED.

Pretty sure you can dim LED's, there is a topic on doing so with Phidgets also on the forum I happened to be browsing before reading this one:

http://www.mycockpit.org/forums/show...3797#post23797

May be of use.

[Westozy]

Thanks guys, I am exploring LEDs.

Gwyn

[JBaymore]

Gwyn,

You don't want to use a car panel dimmer. The reason is it is simply a resistor that allows you to shunt some of the power thru it. A resistor disapates energy as HEAT. So you'll be dumping that heat into the enclosure that the dimmer is mounted in.

For LEDs, you actually need a more sophisticated bit of electronics to "dim": them.

No time to write right now..... more in about a week. Teaching an 10 day intensive college class..... close to 24 hours a day . Maybe someone else will chime in first on the LED dimmer circuit.



best,

....................john

[AndyT]

Try this one.
http://www.web-ee.com/Schematics/LED...LED_Dimmer.htm

[ENKB]

here is a link to a working LED dimmer

http://www.mikesflightdeck.com/led_dimmer.htm


Svein k

[Westozy]

Thanks guys this is great stuff, links like these should be stored on the website somewhere for all to reference. We should build a reference library page, What do you think? Matt, Larry, Trev, Bob?

Cheers guys,
Gwyn

[npbosch]

Hello to all,

Till now I use a light rope for my overheadpanel. Works nice, but takes a lot of space , so I will experiment with high intensity white leds.

A normal led will need around 120-150 ohm as a resistor. (there are alculators available for this).
As I increase the resistor value, less current will go through the led and it will dim.

Suppose that 300 ohm gives a nice minimal brightness.
Then I use a 120 resistor in serie with a 180 ohm variabel reisstor (potentiometer). So I can turn a knob and change the resistor value between 120 and 300 ohm.

What is wrong with that setup? I wil experiment with this. Is there a reason that the above links show more complicated solutions?