backlighting a OC MCDU

[flatlandpilot]

I wanted to backlight the keys of my OC MCDU,
it works, but i'm not totally satisfied, a lot of light comes from between
the keys and housing. then I painted the upper side of the transparant
acryl piece of every key black. that helps a bit, but still not good enough.
How do you close the space between the keys and the housing for light ?
I was thinking about one 3mm. led for each key, but the wiring of that will be a crime.

http://flatlandpilots.nl/coppermine/albums/userpics/10002/DSCF1541.jpg
btw this are 100 degr short 5mm leds

[Matt Olieman]

I know what you mean about the light seeping through the sides.... stuff like that bugs me too. :)

Here's an idea off the top of my head...... ;) how about painting the base of the LED with black paint and only leaving the tip of the LED exposed for light. I've even gone as far as flattening the head of the LED's.

Just a thought :)

[flatlandpilot]

leds become in bigger packages nowadays,
maby it is possibe to mill keys from big leds, paint them and engrave the afterwards
thnx Matt, I go looking for "keysize" and "korrysize" leds ;)

engraving new keys for the OC MCDU was always something I wanted to do,
the (engraving) quality of the keys is "so so"

does anyone use (glas)fibers / fiber-optics to distribute light to keys ?

[Buddym]

I made a dark felt "light-curtain" to go between my panels and the circuit board. I used a razor knife to holes for each button and switch, trimming it slowly until each one just fit thru the hole. it keeps light from sneaking thru the areas between the switch bodies and holes in the panels. Maybe this would work for you.

Buddy

[flatlandpilot]

@Buddy: that sounds interresting, I"ll experiment with that.
The longer I think about it, the more worries I make about the
lighting angle from the led to the buttons. the way I placed the leds
means the light has to make an angle and is not directed straight up
from under the button, that cant be good.

thanks for the tip of using felt (vilt in dutch)
trying to mill that is an interresting project on its self
(and very usefull for other light sneaking problems)
I ll start pressing it between 2 mdf layers, and let you know if that works.

[skalarki]

Hi guys

Backlighting is not that easy as it seems. Almost all led's have the angle of emiting light between 30 and 90 degrees which makes light working only within this angle. Led is not illumitating sidewise, then placing led's between keys has really poor effect. As I've tested for my MCDU project few ideas the best and cheapest is this: http://www.rapidonline.com/Electronic-Components/Switches/Tactile-Switches/Tactile-switch-with-LED/71701
Very bright led and tactile switch 6x6mm.

[Buddym]

That's a nice looking keyswitch, are there matching keycaps for it?

Buddy

[skalarki]

That's a nice looking keyswitch, are there matching keycaps for it?
Buddy

I don't know as I never tried to find out. In my project engraved buttons are designed that way, they are just lying on top of the switch. Before it was impossible, but from the day I bought laser cutting machine everything is so easy to build.