On Tue, 28 Apr 2009, John Watlington wrote: > On Apr 28, 2009, at 7:31 PM, da...@lang.hm wrote: > >> On Wed, 29 Apr 2009, James Cameron wrote: >> >>> On Tue, Apr 28, 2009 at 10:15:47AM -0400, C. Scott Ananian wrote: >>>> I wonder if one could easily support running an LED backwards as an >>>> ambient light monitor in Gen 1.5 - it seems that automatically >>>> powering off the backlight in bright sunlight would lead to a lot of >>>> power savings for most young users. >>> >>> I agree that an ambient light detector and automatic adjustment of >>> backlight would save power. It would happen transparently, magically. >>> >>> But I don't think the LEDs are often specified in terms of their ambient >>> light detection properties. >>> >>> Perhaps it would be better to use a photodiode, or light dependent >>> resistor. >>> >>> Then there's the spectrum of light being received. >>> >>> Then there's reflection from the laptop display itself to consider. >>> >>> I recall we also once had a discussion on whether the camera could be >>> used as an ambient light detector. >> >> you don't want to have to run the camera to detect the light (this will >> eat far more power than you would save) >> >> the LED trick has the advantage of not requiring a change to the case, >> just a single additional drive pin to be able to run it as a detector. > > And where would you place said detector LED, without modifying the case ? > > (I have the pin...)
use one of the existing LED's. I would guess probably the power LED as it has the largest opening (and so would probably be the best choice for detecting light) David Lang _______________________________________________ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
