Notices

I've got absolutely no clue how to make an app. But I just got this idea for the N900...

This app is supposed to dissable all non criticall functions of the tablet in order to increase battery life, in case the user is going to town for more than 24 hours.

What if someone created an app that would do a lot of different power related things. Some of these things should be to unload the wifi part from the kernel, put screen brightness to the lowest level possible, perhaps forcing the cpu to run 250 mhz only, dissable vibration and notification light... All this should happen at just one press of a button... and pressing the button again should put things back to the way they were before.

Of course all this can be done manually but its a lot of buttons to press in order to dissable and then enable all of these features again.

What is your comments about an app like this?

There already is a button that does this, the power button.

Yeah very funny

The tablet was supposed to stay on so you still could use it for sms and IM...

The tablet? Are you talking about the N810?

Are you sure it's possible to re-load the WiFi modules to the kernel after removing them? Or to remove them in run-time in the first place?

Can you post here the scripts to perform all the action you described?

Im talking about the N900.

There is already an app in extras-devel that can unload and then load the wifi module back into the kernel, it's called Wifi Switcher. At my N900 I can unload and then load them back while it has the desired effect as many times as I want without having to reboot.

About the "Underclocking" of the CPU, there is already a lot of talk about overclocking in the overclocking threadhttp://talk.maemo.org/showthread.php?t=39753

I haven't got a clue about the scripts to use...

Quick reply...
I'm against overclocking/underclocking. The manufacturer knows better how to conserve energy and make processor last longer.

But I would be deeply thankful for an application which conserves battery by reducing the functionality of the device accordingly to current needs.

I have already disabled vibration, but I would like to have its modules completely unloaded from kernel (and the vibration motor put out of the device, but it would be too difficult to do).

Sometimes I do use GPS, and it is a must for a mobile device. But I would like to unload its modules when I don't use it.

Sometimes I do take photographs with the camera, and I like them. But I would prefer not to have camera-ui in the background all the time, and I would like to have all camera modules unloaded until I need them, until I manually choose: load camera modules.

Sometimes I do look through the pictures. But image-viewer shouldn't be running in the background when I don't need it.

And what's the purpose of modest running in the background? I have Wi-Fi modules unloaded, thanks to the switcher; I could use cellular Internet, but I don't; and I have 0 accounts on the device. Modest should definitely be killed once and never started again, until I click its icon.

Calendar is in the background, too. I have no events in it; I don't use it; but it starts on startup, and I can bet, that if I kill Calendar once, something will restart it later.

browser - MicroB, which I don't use at all, because I prefer to experiment with beta versions of Fennec.
osso-addressbook
FM receiver
FM transmitter
Bluetooth

Many processes are displayed twice (it maybe irrelevant to battery conservation, but it is unpleasant to look at in the list of processes).

Many processes aren't needed immediately at all; they are just loaded in background seemingly thinking that it will reduce their startup time when they are needed (is it the reason for modest, image-viewer, camera-ui, browser?).

So, yes, I support the idea of such an application completely. As startup, load only drivers of:
touchscreen (absolute necessity);
keyboard (optional);
accelerometer (optional; device orientation);
microphone (necessary for calls);
speakers/headphone (necessary for calls; the only way for the device to alarm you when you don't look directly at the screen - for an incoming call, for instance);
cellular connection (necessary for calls; you aren't going to spend all the time outdoors reading electronic books, playing chess, sketching drawings, typing commands in X Terminal, editing office documents);
Don't load:
Wi-Fi (if you have Wi-Fi around you, then, most likely, you also have a place to charge the device);
GPS (optional; depends on whether you are in a city, taking a metro without GPS fix and knowing your way around, or in a forest, going to get lost and having no reliable reference points);
Bluetooth;
FM transceiver (you have cellular connection, isn't it enough for you?);
camera (unless you are going to take pictures all the time);
modest (unless you are going to receive emails through cellular connection);
browser (unless you are going to browse the Web through the cellular connection);
Calendar (unless you have trouble remembering all the meetings for the period);
image-viewer (unless you are going to look through the photographs or use it as reader for photographed documents);
notification LED (you already have speakers for notifications and alarms);
keyboard backlight (optional);
screen backlight should be made less bright; screen should be turned off as long as possible; how it is done, depends on applications you use during your occupation.

Good luck.

Unless the (hardware) modules are drawing power when the (software) modules are loaded but otherwise "inactive" then the business of unloading and loading them would just use more power?

First, there was a bug: Wi-Fi disabled, but loaded Wi-Fi modules caused power usage even though scanning Wi-Fi networks was set to Never.
It was a bug, which caused fast battery discharge.

Second, having modules loaded uses some power by definition.
Even when the device (phone/tablet/computer/PC) is switched off, it uses battery (it could be used, for example, to switch the device on for a scheduled alarm).
Or: when you tell a PC to shut down, it can still wake itself on LAN if it has some power source because the BIOS is still running.

Similar with a module (in my opinion): if there is a software module loaded, the probability is that the hardware module is in standby mode, not doing anything, but having some power.

The suggestion is to unload the modules and keep them unloaded for a long time. Lower memory usage, lower CPU usage, lower battery usage... and a lot of functionality switched off, leaving only essential processes loaded and running.

If you unload these modules one time, it will not take a lot of power; and if you keep them unloaded for a long time, it will conserve much more power.