LEDs for window switch

[Bitsyncmaster]

My camera is charging so photos to follow.

I ended up using four LEDs in one string with a constant current driver maintaining 20 ma. of current. Except for the color, I like the result. The light output is better than with the bulb. More even light over the full arrows. At 14.0 volts, the bulb power is 1.17 watts. The LEDs use 0.28 watts. The intensity is about the same maybe the LEDs are a little brighter.

I really like this new constant current driver. With this one you could run up to five red or green LEDs in one string. You would be limited to four white or blue LEDs. My old current driver was one less in those strings.

The color I got is a yellow green. I ordered green LEDs but they may have shipped me the wrong ones. There is no marking on these parts so I will never know. Next time I will order a bunch of all the colors they offer so I'm sure to get the correct parts.

[Domi]

Looks like a good improvement.

[Bitsyncmaster]

As always I never can get good photos of LEDs. The one that looks green is the LED one. In real life, that one is yellow/green (more yellow) and the blueish one is solid green (that is the bulb). Anyway you can see the LEDs have a more even illumination of the arrows than the bulb.

[dmc-5180]

That looks Pretty nice! Perhaps try a few more colors to compare with and I think you'll have it.

[Ozzie]

Well done, Dave.
Not only does it fill the graphics better, but I bet that it doesn't feel any warmer than the original non-lit switches.

[Bitsyncmaster]

I found the color problem. Wavelength of these LEDs are 574 nm. Other manufacturers have green at 525 nm. Yellow are 584 nm. Looks like I chose the wrong vendor.

[dmc-5180]

Where do you find a color spectrum chart with that info?

[Bitsyncmaster]

Originally Posted by dmc-5180

Where do you find a color spectrum chart with that info?

The data sheets on each LED specify the wavelength. Looking at different manufacturers data sheets, what one calls green another may call yellow green. There must be a color spectrum showing the wavelength somewhere on the Internet. But then your monitor may not show the true colors depending on how it is set.

Green Light

The visible green light has a wavelength of about 510 nm. Grass, for example, appears green because all of the colors in the visible part of the spectrum are absorbed into the leaves of the grass except green. Green is reflected, therefore grass appears green.window.open('http://eosweb.larc.nasa.gov/EDDOCS/images/Erb/Green_Spectrum.jpg');" border="0" />

[Bitsyncmaster]

Last time I played with designing LEDs I dumped a few hundred dollars buying different parts to test. Here we go again. Just ordered a bunch more to play with this switch lighting.

Green....most are in the 560 to 570 nm range. The 525 nm are special and run 3.3 volts. Blue and white also run 3.3 to 3.8 volts. With that voltage I can only use a string of 3 LEDs and still maintain 20 ma. with the engine off.

Question. Have the people that have installed these switches found the light to be to bright? My 2005 Malibu has white lighted switches on the doors and steering wheel that are much dimmer and I think they look good.

I'm still leaning to using green, I think you will need to match the color in the lighter to look good.

[qumefox]

Originally Posted by Bitsyncmaster

Last time I played with designing LEDs I dumped a few hundred dollars buying different parts to test. Here we go again. Just ordered a bunch more to play with this switch lighting.

Green....most are in the 560 to 570 nm range. The 525 nm are special and run 3.3 volts. Blue and white also run 3.3 to 3.8 volts. With that voltage I can only use a string of 3 LEDs and still maintain 20 ma. with the engine off.

Question. Have the people that have installed these switches found the light to be to bright? My 2005 Malibu has white lighted switches on the doors and steering wheel that are much dimmer and I think they look good.

I'm still leaning to using green, I think you will need to match the color in the lighter to look good.

Maybe do white only, and buy one of these:
http://www.pssl.com/Rosco-Roscolux-Gel-Sampler

Then you could have any color under the rainbow, and i'm pretty sure each color in the sample is large enough to cut to do 2 switches. And stage gels are designed to withstand MUCH higher temps then they'd ever see in a switch.