Powering PC with a clapper. Absolute beginner

Discussion in 'The Projects Forum' started by Dakk, Jan 15, 2015.

  1. Dakk

    Thread Starter New Member

    Jan 15, 2015
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    Hey there! I am an absolute beginner with this stuff, but i thought that since i'm taking electrical engineering, i might as well get started with this stuff.

    I had a thought that it would be killer to power on my PC with a clapper or sort of a knocker or something. Something out of the ordinary. Some questions have risen that i don't really know how to tackle.

    I have no idea where to begin. I've found this kit http://www.canakit.com/clap-on-clap-off-relay-switch-kit-ck252-uk252.html but i don't know if it's a suitable one for my project. I don't even know where to begin. If someone here could maybe lay out a few steps that i can start to cross off or maybe if someone could help me over skype so that i could toss some ideas around with be great.

    Thanks in advance.

    PS: I am running a define r2 chassi if that matters ( for the power buttons sake)
     
  2. wayneh

    Expert

    Sep 9, 2010
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    Personally, I would not want to remove power from the PC. I prefer to let it sleep, and them awaken quickly if I move the mouse or hit the keyboard. That's what I'd look to do - add a motion detector or clapper that can substitute for those other two actions. This strategy would allow you work at just the USB power level, and not have to mess around with mains power.
     
  3. takao21203

    Distinguished Member

    Apr 28, 2012
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    always leave it on?
     
  4. Dakk

    Thread Starter New Member

    Jan 15, 2015
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    Nah, i turn it off when i sleep. This is just so that it'll be a cool little gadget for it.
    I use a SSD so it boots up in a few seconds anyway. Isn't it as simple as adding a little clappercircuit to the powerbutton switch?
     
  5. Dakk

    Thread Starter New Member

    Jan 15, 2015
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    I forgot to mention, i got a great number of qualified people at campus that will help me wit hthe project. They simply ask of me to plan everything etc so that i learn something on the way.
     
  6. wayneh

    Expert

    Sep 9, 2010
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    You could set your computer to automatically restart whenever power is restored. Then all you need is a genuine (external) clapper.
     
  7. nerdegutta

    Moderator

    Dec 15, 2009
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    Wouldn't this be kind of a motion detector? Moving the mouse. I leave my computers on, that way, they are ready to for me in split of a second. I also got a SSD disk and 16Gb RAM.

    If you turn the computer on the a clap, how would you turn it off. clap-clap? And how long time would a clap-clap take, to be registered as a clap-clap, and not two single claps?

    (What would happen if the TV was on in the same room, showing a gameshow and the audience applauded? )
     
  8. wayneh

    Expert

    Sep 9, 2010
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    I think - not sure - you can set a clapper to on-only or off-only.
     
  9. Dakk

    Thread Starter New Member

    Jan 15, 2015
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    I had a thought that maybe there could be a solution where both the button and the clapper was functional at the asme time. You can either control it with claps, or maybe flip a little switch and the nonly the button works?
     
  10. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    I think this would be a most unreliable method of controlling a PC. Any clap circuit is going to have a hard time distinguishing a deliberate clap from miscellaneous background sudden noises. If you intend flipping a switch to enable/disable a clap circuit you might as well just use the PC on/off switch instead ;).
     
  11. Dakk

    Thread Starter New Member

    Jan 15, 2015
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    But the point of the project isn't to make anything easier for me. The point is for me to famirialize myself with electronics other then on the paper.
     
  12. bertus

    Administrator

    Apr 5, 2008
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  13. Reloadron

    Active Member

    Jan 15, 2015
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    My first post here so forgive me if I don't get something quite right.

    If you want to start your PC using a clap, bang or other remote means the first step is to understand what happens when we push the momentary start button on the PC. How does the PC actually start? The front panel start button is a momentary normally open push button switch. That switch, like the reset button and HDD activity LED all connect to a header on the motherboard. One contact of that switch has 5 volt standby power from the PSU and the other is common. The 5 volt SB power is provided through a pull up resistor and is present anytime the PC has power and the rear On/Off switch is On. Momentarily pushing the front panel start button places a logic low on that line. This is passed through the motherboard (with things in between) to the motherboard's main PSU connector. On that connector with an older 20 pin connector pin # 14 is latched and held at a logic low and the PSU starts, fans power up etc. On a newer 24 pin connector it would be pin #16. Those are the power supply on (active low) pins. Between the motherboard header front panel push button and the PSU connector the motherboard takes care of things like wake on LAN and other remote start features.The wire from pin 14 or 16 should be Green and the only Green wire in the bundle. This is true of most PCs.

    So to remotely start the PC you can go across the front panel PB but... you only need a momentary pulse (logic low) of maybe a second or less to start the PC or placing and holding the PSU connector pins I mentioned at a logic low and holding them there. A "clap" switch is clap on and then clap off. The problem becomes you need to shut down the PC using normal shut down procedure. PCs really don't like hard shut downs. :)

    The best solution would likely be to build your own little microphone and amplifier circuit that triggers a One Shot multivibrator that will place a logic low across the front panel push button. Pulse duration between .5 to 1 second should work. That would be my guess anyway. :)

    Ron
     
  14. Dakk

    Thread Starter New Member

    Jan 15, 2015
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    If i understood this correctly now: If it is a closed circuit( a complete loop where current can flow) between the + and - pinholes on the motherboards power holes, it starts? I looked a little on momentary switches.

    Btw, thanks for your awesome reply!
     
  15. Reloadron

    Active Member

    Jan 15, 2015
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    Yeah, here is what I am saying. If we lookie at the PC front panel push button used to start the PC it will look about like the drawing below.

    PSU Start.png

    The To Motherboard is held at a logic high through the 10K pullup resistor. When you push the Start PB it will momentarily pull the To Motherboard line to a logic low. Just a momentary low for the duration the button is held low. The 5 Volt SB (Stand By) is always present, even when the PC is off. That low pulse that we create when we momentarily push the start button is what starts the PC and will latch the pins on the big power supply connector on the motherboard as I mentioned earlier.

    So, if I take a microphone for example and make a small simple audio amplifier I could use that signal to trigger a One Shot Multivibrator which will output a pulse of some duration depending on my RC time constants of my one shot. Guessing .5 second would be more than adequate. I place that pulse across the PB switch. Now the pulse starts the computer rather than the PB switch.

    Ron
     
  16. Dakk

    Thread Starter New Member

    Jan 15, 2015
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    Do you think that my idea sounds like a good project to sttart with? I am reading electrical engineering and just finished introductory to circuits as well as i have a bunch of competent people at the electronics-"club" that will help me
     
  17. Reloadron

    Active Member

    Jan 15, 2015
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    I saw that mentioned earlier. Do I think it's a good project? Yes, I don't see it as a bad project. Any project, regardless of how simple or complex is a good project if you come away from it learning something. OK, in this case let's say you take a microphone of sorts and do as I mentioned. The mic picks up a sound, be it a bang or whatever. You convert that sound to an electrical pulse, that pulse can do any number of things. Start a PC, start or stop a counter, get the idea? The circuit is no more than a building block, you put the blocks together. Yes, any project you walk away from learning something is a good project, some more gooder than others but all good. :)

    That's my take on it anyway.
    Ron
     
  18. Dakk

    Thread Starter New Member

    Jan 15, 2015
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    If i understood it correctly, basically if i plug this to the motherboard (i've bult tons of computers, so i know how those stuff works, just not how the button itself works), it should work? Or did i misunderstand you?
     
  19. nerdegutta

    Moderator

    Dec 15, 2009
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    How about adding this:

    http://www.aaroncake.net/circuits/lightdrk.asp

    You turn on the lights in the room when you enter, and the computer starts, when you leave, you turn off the light and clap your hands. To celebrate your achievements this day. :D
     
  20. Reloadron

    Active Member

    Jan 15, 2015
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    We start the computer by just pushing, momentarily, a normally open push button as I drew it. All we are doing is applying a momentary logic low to the motherboard. The key word here is momentary. Then in turn the motherboard latches a PSU ON line low going to the PSU. All you want and need to do is bridge that button with a negative pulse. We don't want to latch it but simple pulse it to simulate what happens when the button is pressed. Once the PC is on, it's on. The reason we pulse it is because once the PC starts if the start button is held the PC will do a hard shutdown. If you walk up to a running PC and just bump the start button, nothing happens. However, walk up to a running PC and press and hold the start button for 5 to 7 or so seconds and the PC will do a hard shutdown. Literally the PSU will shut down. Give me till tomorrow and I'll make a basic drawing.

    Ron
     
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