How to dim a monitor

Discussion in 'The Projects Forum' started by Moonstar78, Jul 14, 2011.

  1. Moonstar78

    Thread Starter Member

    Jul 7, 2011
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    Hi everyone!

    Its me again. I just want to know if its possible for a lcd monitor to dim using some circuit or thru a low power supply..

    If anybody got this idea, please, i need help... I need this for my project.

    Thank you and more power!
     
  2. wayneh

    Expert

    Sep 9, 2010
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    How dim? You could probably hack a switch into the fluorescent backlight, to turn it off. I'm not sure how the video card in your computer would react to that. Is there a reason you can't use a software solution? Way easier than hardware.
     
  3. iONic

    AAC Fanatic!

    Nov 16, 2007
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    Not without hacking onto your monitor and even then I'm not sure it's reasonably possible. Most Operating Systems already have monitor dimming.
    I just press a function key and the down arrow and I can dim my LCD. I also have additional software that turns the screen saver from a blank screen, but still powered to completely off. It could vary well be a change in the output signal from the graphics card that creates the dimming, which means that you might have to hack the motherboard's On-Board graphics or a separate graphics card added to the Mother Board.

    Not a particularly safe project without knowing a computers workings inside and out!
     
  4. Moonstar78

    Thread Starter Member

    Jul 7, 2011
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    Ok then. Since this isn't possible to do it. would it be safe to make my monitor turning ON/OFF intermittently? i have a monitor its power depends on a relay switch thru a digital timer. When time is up it will automaticaty cut the power of my monitor thru a relay.

    Do you have any idea or a circuit protect for the power line of my monitor to make safe?

    Any suggestion will be appreciated... More power!
     
  5. iONic

    AAC Fanatic!

    Nov 16, 2007
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    What really is your goal here. Turning your monitor off intermittently while working on your computer is undesirable and turning your monitor off intermittently while not working on it is still wasteful. Why not just turn it off when you are not working on it?
     
  6. Moonstar78

    Thread Starter Member

    Jul 7, 2011
    39
    0
    I want to use this method in my internet cafe. i made a coin slot operated PC.

    Do you know where to get a delay relay schematic diagram?
     
  7. iONic

    AAC Fanatic!

    Nov 16, 2007
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    But you are still not describing the full scenario...when it should shut off, when it should turn on...

    A delay relay schematic can be made with a simple 555 timer circuit. A delay on and/or a delay off.

    Will you use the coin slot mechanism to trigger the monitor on and off?
     
  8. strantor

    AAC Fanatic!

    Oct 3, 2010
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    why not hack into the VGA cable, run pins 1,2,&3, (red, blue, green signals) through a relay. That should kill your display without constantly cycling power to your monitor. Maybe someone who is smarter than me should comment on this, because I really don't know what I'm talking about. The RGB signals could be too high frequency; VGA cable could be a transmission line; adding a relay could jack up your R's, L's, & C's; I don't know. guess it wouldn't hurt to try.

    Edit: if you do try this and it's jacked up, try lowering your resolution & refresh rate. that lowers the signal bandwidth, better chance at sucess I think.

    more info here:
    http://en.wikipedia.org/wiki/VGA_connector
     
  9. wayneh

    Expert

    Sep 9, 2010
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    A bright monitor is more likely to attract internet moths to your coin slot than a dark one. I'd leave it on. ;)
     
  10. SgtWookie

    Expert

    Jul 17, 2007
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    Presenting your customer with a blank screen when their time runs out without a warning will likely get you some irate customers. Besides, simply blanking the screen would leave whatever applications they had open, still open.

    There are ways to accomplish access control without making physical modifications to the system. My local library uses some kind of software package to control access to computers; a library customer swipes their library card through a card reader, and they get assigned to an available computer for a period of time. They then go to the computer, and can log on to their account. A small count-down timer is continuously displayed near the top of the monitor, so that the customer knows exactly how much time they have left before their session is over. When the session times out, all applications that are open are closed, and the system logs them out.
     
  11. strantor

    AAC Fanatic!

    Oct 3, 2010
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    Good point. who is going to walk into an internet cafe where all the screens are off? Get energy efficient ones and leave them on. there is software out there that will lock down a computer after after a given time as I'm sure you are alreay aware.

    If you wanted to leave the screen on and still employ your coin device, you could have the device lockout the keyboard & mouse.

    By locking out the keyboard+mouse or the monitor, I think you will have severely agitated customers (non-return customers) due to the fact that if they don't (and they won't) finish what they are doing (i.e. log out of they myspace or close dirty pics of their girlfriend) before the timer runs out, the next person will be able to see that. This is especially if your computer runs slow (I estimate after the 1st week it will be slower than molasses if you don't install some content control) then they can blame you (even more justifiedly) for the problem.
     
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