The idea of this brainstorm is to add an "automatic" option to the Backlight time-out menu in Display settings.

The backlight time-out could be set to automatic (e.g., between a minimal and maximal value). If the user taps the screen (or uses the screen lock switch) to turn the backlight back on right after it dimmed automatically, the interval until the next auto-dimming should increase (e.g., double). If the user does not attempt to bring the backlight back on, the next auto-dimming interval can be short (e.g., the minimal value can be utilized).

Such algorithm would mean a good tradeoff between user comfort and battery life.

If you folks think this is a good idea, please vote for this brainstorm at:
http://maemo.org/community/brainstor...light_time-out

Your feedback is appreciated!

Hey, good idea.

On the same token, it would be interesting to add accelerometer input to your algorithm. For example:

If the accelerometer changes any value, however small, it would count as a "user tap". This way, just by holding the N900 in your hands to read something (or watch something) it won't turn of the screen.

maybe add some options to turn off this feature, when the action is not desired.

Hi soeiro, I like the accelerometer idea. That makes sense. However, the device movement should probably not prevent the device from auto-dimming completely, just make the interval longer... so that the device does not staly lit all the time while you are travelling for instance.


Similarly, the fact whether or not anything on the screen has changed could also play role...

One of the moments when I fight the auto-dimming is application upadtes (here the progress bar is moving), or when I connect my laptop to the Internet via the N900, I want to watch the changing data traffic figures on the phone (I know I can check the "display staus lit when charging" option, but I want my N900 to be smart and figure it out itself when I want it to be lit - I do not want it to be lit when just charging). Other times, a one minute time-out works well for me. I know is is impossible for the phone to guess the auto-dimming perfectly, but I think some degree of artificial inteligence in this regard can be achieved rather easily..

Nice looking forward to this...I also had a similar idea although mine was a little more complex:

1) Use a command line that takes off the key board lights (You wont need key lights at day time) when Its night you can use a command line to turn on the key lights again. Or better yet have ability to set keypad lights to turn on at a certain time of day (7:00 pm or so).

2) Use a command line to power down the LCD lights to 80% or so...(20% battery increase; I'm not refering to brightness as this is completely different)...also have option to take off lcd lights after a period of time (your idea)

3) Use a command line to under clock the device by 50 or 100mhz. (Dont think the n900 needs the full 600mhz anyway)

Option three isn't nessecary, but the first two options I know would be a real life safer as I did them on a phone (N-Gage) and was able to double its battery life...and trust me, I ain't exagerating. In fact I'm pretty sure if this concept was done on any phone it would surely have a similar effect. This is due to the fact that besides clock rate (600mhz) the lights are the ones taking up the most battery life and they are almost always on, the same can be said for any phone.

Maybe a configurable option. Two examples:
1) Easy one:
a) User starts the back-light monitoring application, chooses the "accelerometer mode" and switches to the applicatino that she wants to use. The backlight-monitoring is active, but in background.
b) While reading, browsing, playing or handling the N900, the accelerometer keeps it lit.
c) After finishing the activities, the user disables "accelerometer mode" and the N900 won't stay lit while driving.

2) Difficult one:
a) Each application can query the backlight-monitoring thread and set some values. Just like video players or games can do (I guess).

I second that. I my case I usually use the keyboard just to make it easier to scroll reading materials, but the lights wouldn't need to be on (you just hold your finger on the arrow key).

Are you sure that the system doesn't already do this?

The N900 already controls it speed. If you install Conky you can see that it stays most of the time idling at 250MHz. I don't think it can go below 250MHz, though (I've never seen it).

another nice feature would be to light-up when it's still for a long time and suddenly someone grabs it. (I don't know if the accelerometer drains up the battery, maybe it will be impossible to have it always on without significant battery drain)
That way when you want to check the time, or if the update or the download has completed, you just need to grab the phone off the desk.
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