Smart LCD birght/dim...

Sean Anderson keep.brain.from.freezing at
Sun Apr 13 15:47:28 CEST 2008

On Sun, 2008-04-13 at 14:38 +0100, ewanm89 wrote:
> On Sat, 12 Apr 2008 02:50:11 +0200
> "Marco Trevisan (Treviño)" <mail at> wrote:
> > Since Freerunner won't have an hardware light sensor to set its LCD 
> > brightness, I got some ideas about smartly changing the luminance of
> > the GTA02 screen to save its battery (still with an unknown life
> > time :/). Of course they aren't and never will be precise as an
> > hardware sensor is, but it's the only thing we have:
> > 
> > 1) Setting the brightness following the hour of the day: also if the 
> > phone can't know if it's sunny or cloudy, neither if you're indoor or 
> > outdoor, it's clear that just knowing the hour of the day, the date
> > and your latitude (to be set once via GPS) the phone can easily know
> > when the sun will rise and set, and so it will be possible increasing
> > or reducing the LCD brightness.
> > Also if you're indoor, I guess that when the sun is "gone" you won't 
> > need so much luminance...
> > 
> > 2) Using personal profiles that follow your habits: you could define, 
> > for each hour of each week day the "presumed" luminance, using
> > something like a calendar. I mean, if on working-days I generally
> > stay indoor every day from 8:30 to 13:00 and from 15:00 to the 19:00
> > I figure that on these intervals I don't need all the LCD power, so
> > I'll set in my "calendar" that on such interval I'll be indoor...
> > I guess that many of you would follow a routine durning the week, why 
> > don't educate your phone for it!?
> > 
> > 3) Setting the luminance following the weather. Of course I've no
> > light sensors, neither a barometer :P, but if I've a working
> > connection available I could use the weather data downloaded every
> > few minutes (60, for example) from internet to change my screen
> > brightness (of course merging these informations with points 1 and 2)
> > 
> > What do you think about them?
> > I do think that they are really simple to implement, and that also if 
> > they won't guarantee a perferct result, they could be a "smart"
> > workaround.
> > 
> GPS signal drops in cloudy conditions, and is usually non-existent
> indoors... this just leaves the 24hour cycle of the spin of the earth
> to worry about, all we need know is position, and rise/set times to
> sort that problem?
These all sound like rather extravagant power-saving means that would be
unlikely to save a great deal of power. It's maybe worth implementing if
someone has the time to add this neat little power-saving feature, as
part of power management - but it would be my guess that more battery
power could be saved by simple things like turning off GPRS when it is
not in use.


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