Smart LCD birght/dim...

ewanm89 ewanm89 at googlemail.com
Sun Apr 13 15:57:43 CEST 2008


On Sun, 13 Apr 2008 14:47:28 +0100
Sean Anderson <keep.brain.from.freezing at gmail.com> wrote:

> 
> 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 3v1n0.net> 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.
> 
> Sean.
> 
> 
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Agreed, the GPS would draw a lot of power, along with the GSM radio,
bluetooth radio and wifi radio, I was only pointing out that it is
technically possible with given hardware, not that it is a good idea.

-- 
Ewan Marshall (ewanm89/Cap_J_L_Picard on irc)

http://ewanm89.co.uk/
Geek by nature, Linux by choice.
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