Battery Life Part 2

[christo930]

Would it be reasonably possible within the projected price and specs to bring the battery life up without the need for a heavy expensive battery? Would using a high quality reflective screen with a front light that can be turned on and off and maybe even multiple levels of brightness ala iPaq add much to battery life? What about the use of a power management system? This would seem to be especially effective with applications that were not games. For example, when reading a webpage that has already been displayed requires little processor power. It may take me 10 minutes to read a web page with only scrolling and the cpu can be throttled back while this not being used. Applications can also set the clock speed to what is appropriate for the application or game being run. Is it too late to even think about this kind of stuff (rather than optimizations in the bios)?

Chris

 

[JakeK]

Light isn't always good. I like a handheld to be a bit heavy in the hands, not to the point where you have to actually try to hold it. For me, 10 hours is more than enough as I am always around a power point or a PC.

 

[Chip]

QUOTE
Would it be reasonably possible within the projected price and specs to bring the battery life up without the need for a heavy expensive battery?


No. Lithium polymer batteries already have the best power-to-weight ratio around. The only way to get more juice is to add more battery.

QUOTE
Would using a high quality reflective screen with a front light that can be turned on and off and maybe even multiple levels of brightness ala iPaq add much to battery life?


No. The LCD panel on the Pandora is LCD backlit. It is as efficient as you're going to get without going reflective-only, which would be a terrible idea.

QUOTE
What about the use of a power management system? This would seem to be especially effective with applications that were not games. For example, when reading a webpage that has already been displayed requires little processor power. It may take me 10 minutes to read a web page with only scrolling and the cpu can be throttled back while this not being used.


Entirely up to the programmer. The hardware is specifically designed for low-power, handheld devices. If the programmer wants to write energy-efficient applications, there are plenty of tools at his disposal to do that.

QUOTE
Is it too late to even think about this kind of stuff (rather than optimizations in the bios)?


For the most part, yes.

 

[JakeK]

So Chip the screen isn't going to be reflective? If so that is freaking awesome!

What is the purpose of a reflective screen, it just makes it hard to see in lit up areas.

 

[icurafu]

LCD backlit?

Seriously? When was this confirmed?

I thought a feature like this would be listed in wold in either...

http://www.openpandora.org/

or

http://www.openpandora.ca/

 

[Game_over]

I love your sarcasm (I hope that's sarcasm).

 

[imec]

I thought LED backlights haven't come that far, or am I mistaken?

 

[JakeK]

They are used in some laptops already. Sony uses them in there VAIO notebooks (higher end slim ones).

 

[nubie]

I thought LED backlights haven't come that far, or am I mistaken?

As far as what? All 3 versions of the GP2X screen use them, and I personally installed 2 LED's and backlight material into the LCD in the portable Genesis in my sig.

 

[Squidge]

Would using a high quality reflective screen with a front light that can be turned on and off and maybe even multiple levels of brightness ala iPaq add much to battery life?

The LCD backlight can already been turned on and off and has multiple levels of brightness.

What about the use of a power management system? This would seem to be especially effective with

Already in there, cpu speed is changed depending on processor load.

 

[icurafu]

I love your sarcasm (I hope that's sarcasm).

Sadly not.

I misread LED backlit, instead of LCD backlit.

Anyway, another fool made the same mistake. ...Or maybe I should've pretended it was sarcasm. (Mocking the other guy)

 

[imec]

I thought LED backlights haven't come that far, or am I mistaken?

As far as what? All 3 versions of the GP2X screen use them, and I personally installed 2 LED's and backlight material into the LCD in the portable Genesis in my sig.


Well, the last LCD monitor I took apart used a cathode tube or something, I took apart my DS also, but didn't dismantle the screens. I realize where this assumption came from, I was quite into the whole DIY projector thing a few years ago and LED lighting hasn't become available until now (due to various elements, such as dissipating the light evenly). So yeah, that's where that came from.

 

[Chip]

LCD backlit?

Seriously? When was this confirmed?

Apparently I'm retarded on two counts. I mistyped LCD when I meant LED, which I swear I read somewhere in here. Of course I can't find it now, which may be because it never actually existed. Can someone with access to the hardware please confirm or deny an LED backlight?

So Chip the screen isn't going to be reflective? If so that is freaking awesome!

What is the purpose of a reflective screen, it just makes it hard to see in lit up areas.

I meant reflective as in not backlit (like the original GP32), not as in glossy. But it looks like it won't be glossy either - http://www.gp32x.de/board/index.php?showt...mp;#entry573484

Just in case anybody is still confused, there are three types of LCD panel: Reflective, transmissive, and transflective.

Transmissive is the most common type. It requires a backlight of some type to shine through the LCD panel. Traditionally, most transmissive LCD panels larger than an inch or two used flat cold-cathode (florescent) backlights. LED backlights for larger panels are very new, but exist. The new Macbook Pros, for example, have LED backlit panels.

Reflective has no backlighting and relies on ambient light or, in some cases, front lighting.

Transflective screens are a combination of the two. The LCD panel is partially reflective. This allows a backlight to work in low ambient light conditions, while strong ambient light (direct sunlight) will reflect, maintaining readability. These are significantly more expensive than the other two types, and usually only come in small sizes for cell phones.

 

[christo930]

So Chip the screen isn't going to be reflective? If so that is freaking awesome!

What is the purpose of a reflective screen, it just makes it hard to see in lit up areas.

I don't know if you have ever used an iPaq, but it's probably the best small screen I have ever seen. It's beautiful in low light conditions, medium light and bright sunlight. I use mine mostly for reading and I can read this screen for hours without any eye strain at all. Backlit screens are nice, but fail totally in the sunlight.

Anyway, it was just a question. I would rather have a more efficient machine with a smaller/lighter/cheaper battery. LED back lighting is pretty energy efficient though, although it still washes out in the sunlight.

Chris

 

[christo930]

So Chip the screen isn't going to be reflective? If so that is freaking awesome!

What is the purpose of a reflective screen, it just makes it hard to see in lit up areas.

A reflective screen uses ambient light to light up the screen. They are especially good for outdoor use. Just about any screen designed to be used outside would use a reflective screen with a front light that can be turned on and off. A non reflective screen is almost impossible to see outside in the sunlight. The iPaq is the best implementation of this screen that I can point to. Now, these things are upwards of $500 so they can afford to use the best screens. It's also really good for to use a cheaper screen while maintaining readability. For an example of this, if you have an original gp32 (non backlit) open a book on it and open a book on a gp2x and try reading. The gp32 (if you are in a well lit area for the non-frontlit version) won't give you headache at all, while the gp2x will kill you. The front lit gp32 is also excellent for reading. IF you want readability on a backlit screen, you have to use a really good quality screen. Presumably the Pandora will have an excellent screen.

 

[JakeK]

So then what is the Pandora implementing. Are we going to see a Pandora screen that isn't going to kark itself in the sun or will it be fine?