Rockbox General > Rockbox General Discussion
Sansa e200 - wheel light fade in/out, also display fade in/out
krazykit:
--- Quote from: casainho on November 07, 2007, 08:38:27 AM ---Its a question of harmony, as the natural light of sun reach us, fading in on morning and out on evening. Rapid transitions are not natural to humans and I believe that behavior passes some stress to us, for example in illumination on our houses (at least in mine, here in Portugal).
--- End quote ---
To avoid this rapid transition, you could just keep the wheel light off, of course.
scharkalvin:
Well there was a patch to adjust the back light intensity of ipods and this had to be done in software (this is a pulse width modulation of the power to the back light).
So it's something that can be done. I'm not sure how the ipod hardware controls the back light, there may be less software overhead involved in this case.
Anyway, there will always be un-supported patches and builds for the kind of off the wall stuff that some people just can't live without, and the rest of us don't want to waste cpu cycles on.
casainho:
--- Quote from: krazykit on November 07, 2007, 11:43:24 AM ---To avoid this rapid transition, you could just keep the wheel light off, of course.
--- End quote ---
Thats what I do now, because I have low bright selected for display and the wheel light is to strong and does not let me see in a good way the display. It would be nice to have low bright, less than display, in the wheel light.
--- Quote from: scharkalvin on November 07, 2007, 11:58:09 AM ---Well there was a patch to adjust the back light intensity of ipods and this had to be done in software (this is a pulse width modulation of the power to the back light).
So it's something that can be done. I'm not sure how the ipod hardware controls the back light, there may be less software overhead involved in this case.
Anyway, there will always be un-supported patches and builds for the kind of off the wall stuff that some people just can't live without, and the rest of us don't want to waste cpu cycles on.
--- End quote ---
Yes, pulse width modulation PWM as I suspected ;) To not see flicker, at least 5 kHz of PWM, to get 1% increments o duty-cylce at 50 Hz, so, at 50Hz no flicker to human eyes :-)
IDEA to implement:
Lets assume that we have one variable - Tick_5kHz_Counter, that is incremented every 5 kHz (maybe with a tick of 5 kHz) and goes from 0 -> 99 every time.
Duty_Cycle is a variable that keeps the percentage of light, from 0% till 100%. Duty_Cycle could be updated on an entry menu with name "Wheel options".
if (Tick_5kHz) {
if (Tick_5kHz_Counter < Duty_Cycle) {
Wheel_light_IO = ON;
}
else {
Wheel_light_IO = OFF;
}
}
}
Tick_5kHz = false;
I paid one time for CPU and for memory, I pay constantly for energy on battery! I prefer CPU cycles for dimming the light than for videos. My sansa have a lot of CPU power and bytes for code, but I would prefer to saving battery, and diming light can save battery, maybe more than can spend on the cycles to do that.
Llorean:
The PWM method of handling the iPod 5G screen brightness was actually turned down and investigation was done to find a hardware method to handle it, since evidence suggested it existed.
JdGordon:
--- Quote from: casainho on November 07, 2007, 12:14:27 PM ---I paid one time for CPU and for memory, I pay constantly for energy on battery!
--- End quote ---
you know that if the light is on then more batter is being used right? so you end up using more power... especially when you want to get the cpu doing more work which does nothing more than make the display look a bit nicer....
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version