Dim LCD based on ambient light

neon_eddy · 12-01-2005, 12:16 AM

I know there ahve beena few threads on this.. but I couldn't find much in the way of answeres.

1) Is it jsut a matter of adjsuting the Hhigh Voltage line to the CCFL? I would assume it would be better to do that than pull the voltage down for the whole thing, although maybe easier.

2) Maybe someone could help me / all of us, with some plans for building such a regulator?

No, software gamme control isn't what I'm thinking.. all gamma does is shift all pixel values darker, less white .. but the black the same.. because even a black image on a screen makes light ..

I'm just saying it would be nicer to have it use a photocell of somekind to control the actual luminance of the CCFL.

just one more thing for me to break :-)

Maximus · 12-01-2005, 01:19 AM

JC and Scouse is working on a dimming solution:
http://www.mp3car.com/vbulletin/show...ht=Autodimming

...and there are VGA controllers with dimming input.

...and there are software controllable VGA controllers.

(with "VGA controller" I mean the VGA driver board connected to the panel itself)

I intend on using software since my car allready have a sensor that I can access through the car's internal bus.

/M

coucouillu · 12-01-2005, 05:06 AM

I am working on a backlight upgrade based on OSRAM Golden Dragon leds with photo-transistor which increase or decrease backlighting in fonction of quantity of ambiant light. When ther is direct sun light on the screen, the backlight will work to the mawimum of capabilities.

neon_eddy · 12-01-2005, 07:02 AM

So, having some sort of variable resistance on the HV line won't work? ..

I guess I feel my current backlight does greta in the sun... but now it's just too bright.

I read a bit on the Scouse thing, but it looked like that project stopped.. I just figured it couldn't be that ahrd to make an variable ristsance circut based on light input ... I'll see what I can do via google.. I had jsut wondered if anyone else had done this already.