Glow in the dark keys

[Kiga]

You know, we're talking about a keyboard backlight, not something able to illuminate a complete room.

Most of the time, a few low power leds on a PWD line to change the brightness are far enough for that kind of use.

I don't want to lose 10 min of battery for a backlight :mellow:   and it will be more than 10 minutes because I use it to code so backlight would be always on.

Backlight is just a superflous fashion accessory wich cost money and battery power . You can have the same result with glow-in-the dark and  the screen already make light.

I don't want to have a iphone or a samsung, i just want a device that are as functional as possible.

 

[Neelix]

So you don't want it at all but would keep it turned on if you had it?  seriously?

- Neelix

 

[WizardStan]

I don't want to lose 10 min of battery for a backlight

An LED uses 30 to 60 milliwatts of power. Let's go max 60. We need... 4 leds to illuminate the keyboard. 4*60 = 240 milliwatt.The Pandora's battery is 4200 amphour at 5volts.

4200 amp hour * 5 volt / 0.240 watt = 10 years. The Pandoras battery could run 4 LEDs for 10 years. When the rest of the system can consume that same 4200 amp hours in 10 hours, that's 2100 watts. By adding a 4 LED backlight you are going from about 2100 watts to 2100.240 watts. You are losing 4 seconds, at most, even if the LEDs were running at full brightness the entire it was in use.

 

[Kiga]

Thanks for precision and calculation

It seems curious because screen backlight is  one of the stuff which cost most battery power, isn't  it backlighted by led?

 

[Hồng Thất Công]

I think you're confused.  We're talking about keyboard backlight and not screen backlight

 

[levi]

As far as I'm aware the LCD we use is backlit by a CFL anyway, which is a lot more power hungry than a few LEDs are.

 

[_wb_]

I don't want to lose 10 min of battery for a backlight

An LED uses 30 to 60 milliwatts of power. Let's go max 60. We need... 4 leds to illuminate the keyboard. 4*60 = 240 milliwatt.
The Pandora's battery is 4200 amphour at 5volts.


4200 amp hour * 5 volt / 0.240 watt = 10 years. The Pandoras battery could run 4 LEDs for 10 years. When the rest of the system can consume that same 4200 amp hours in 10 hours, that's 2100 watts. By adding a 4 LED backlight you are going from about 2100 watts to 2100.240 watts. You are losing 4 seconds, at most, even if the LEDs were running at full brightness the entire it was in use.

Your calculation is off by a factor of 1000. Our battery is 4200 milliamp hours. So we're not talking 4 seconds, we're talking 4000 seconds or about one hour. It's not a huge deal if you really want it, but it's not negligible either.

 

[Kiga]

Your calculation is off by a factor of 1000. Our battery is 4200 milliamp hours. So we're not talking 4 seconds, we're talking 4000 seconds or about one hour. It's not a huge deal if you really want it, but it's not negligible either.

Thanks! Seems more realistic!

1 hour is way too much for a (useless in my opinion) backlight but if we can desactivate it  contrary to usual phones it can be done. However i prefer without backlight because it will be more expensive with.

 

[Binky]

^ I'd also be quite impressed (and worried) if the pandora could use 2.1kW

 

[Asiyura]

An LED uses 30 to 60 milliwatts of power.

Those are already high-power ones, you can find SMD leds needing less than 10mW that would provide far enough light for a keyboard backlight.

Your calculation is off by a factor of 1000. Our battery is 4200 milliamp hours. So we're not talking 4 seconds, we're talking 4000 seconds or about one hour. It's not a huge deal if you really want it, but it's not negligible either.

As I said, those are already "high" powered leds, there even exist 1mW leds…We only need a few mC to light up a keyboard.

 

[Klumpen]

Seriously, who would be so dumb to have the back light switched on all the time?

So you don't want it at all but would keep it turned on if you had it?  seriously?

- Neelix

It seems so.

 

[Kiga]

Seriously, who would be so dumb to have the back light switched on all the time?

So you don't want it at all but would keep it turned on if you had it?  seriously?

- Neelix

It seems so.

It seems that you and Neelix are not able to read.

 

[Klumpen]

If you want the additional battery life, just turn the back light off. Oo

What hinders you? I always thought it would be a good thing to have options.

 

[WizardStan]

Your calculation is off by a factor of 1000. Our battery is 4200 milliamp hours

Ah bully. I screwed it up. That is actually a lot.

ose are already high-power ones, you can find SMD leds needing less than 10mW that would provide far enough light for a keyboard backlight

Yeah, I was going for an upper bound. If I hadn't screwed up the numbers it would have been quite impressive.

 

[Binky]

We only need a few mC to light up a keyboard.

How is any quantity of charge going to light up anything?

 

[Asiyura]

We only need a few mC to light up a keyboard.

 How is any quantity of charge going to light up anything?

Whoops, forgot the "d" of candela, replace "mC" by mcd

 

[_wb_]

Compared to the screen, a keyboard backlight does not consume a lot of power. Enough to disable it when you don't need it, but not enough to not enable it when you can use it.

I wouldn't object to having a keyboard backlight, but I certainly don't consider it a "must have" feature. Glow-in-the-dark keys however are a "don't want" feature - they would probably not manage to "charge" (unless you can keep the lid open with the device well exposed to daylight), so it would be quite pointless, but even if they are "charged", it would suck to not be able to disable it.

 

[Hồng Thất Công]

Yeah, my wife said if the light is out, you are going to bed Mr.! So backlit or not not important to me

 

[comradekingu]

How do you know its your wife if you cant see? You should use this rhetoric to enable play if you often get matters confused. Life is simple.

 

[Hồng Thất Công]

How do you know its your wife if you cant see?

^Maybe I don't want to know