Remote PC 'power up'

[kramer]

I'm sure there is a very simple solution to this but I only have a very basic knowledge of elctronics, but I am a 'dab hand' with a soldering iron!

I want to be able to power up my computer at my holiday home so that I can look at a cctv output.
I don't want the PC on standby all the time.
I need to 'short' the power up pins on the motherboard.
I figured if I used an old mobile phone and took the voltage from the 'vibrator' I could use that voltage to power a relay and create the switch.
Unfortunately the voltage output for the vibrator is only around 1.5v and not enough to 'trip' the relay I bought, which appears to need at least 3v.
I need to know how to increase the voltage to cause the relay to work. All articles on inverters seem to be about much bigger voltages.

If anyone can answer the question or suggest any alternative approaches I would be very grateful as this is the last piece of the 'jigsaw' to get the whole thing working.
Thanks

[ben23]

ok first your going to need it to work like this

phone rings - relay closes - computer starts up
you hang up - relay opens - computer keeps on running

to turn off
phone rings - relay closes - computer begins to shut down (as long as you have configured the Power settings in Control Panel to do so)
you hang up - relay opens - computer proceeds to shut down

you observe to see whether you can access the computer anymore, if you cant, your successful, if you can, you need to ring, and let it ring until you lose connection, which will do the same thing as holding the button on the front of the computer until it turns off.

you will need a TTL type relay (which work on tiny voltages) to switch the green wire from the computer power supply (turn-on) and one of the black wires from the computer power supply (ground) just splice into these two wires, just splice and solder and tape/heatshrink.

I will have a look for a suitable relay and get back to you with the details.
This is actually quite a good idea.

[kramer]

Thanks for the reply.
First of all, I have no concern about turning the computer off because once it has started up, and sent me its IP address, which I have already sorted, I can take control with PC Anywhere and shut it down. In the event of that failing I will have it set to hibernate after a set time.
Having read about other projects here, it looked to me like I should be looking to maybe use a transistor as a switch rather than a relay, but I don't know what type or rating or how to wire it up. Relays I understand, transistors I don't!

[ben23]

yeah a transistor type of switch would be good but i too have no idea how to make one, a transistor switch is a solid state relay basically.

rating wouldnt need to be anything high, as the start up current is only momentary and very small (<200mA)

[tikbalang]

check your bios. newer motherboards allow power up by:

a. scheduled time set in the bios
b. triggering the modem
c. triggering the LAN card
d. triggering the mouse
e. triggering the keyboard
f. triggering a usb device

bioses can also set the power state upon AC power loss to:
a. RESUME - start up when ac power is restored
b. STAY OFF

if yours can only stay off, you need this:
http://www.pealefamily.net/tech/newmame/captrick/

it switches on the pc as if someone pressed the power button.

i would recommend triggering the modem. similar to ben23's suggestion but without using a relay device. it only requires the pc to be connected to a phoneline thru a modem. of course the bios and OS must also support this. for win2k/XP, you need to set the modem to bring the pc out of standby (device manager).

http://img219.imageshack.us/img219/6540/poweruptt8.gif



to turn the pc on:

1. dial the number modem is connected
2. modem gets RING, triggers pc
3. pc executes login/startup scripts
4. you access and shutdown the pc using remote software

if the modem is external, it has to be always ON to monitor the line.

start --> turn of computer --> standby
i am curious as to how you define standby. to me, standby = hibernate, where the pc is restored to its last ON state. i am unfamiliar with this as i do not use this feature.

start --> turn of computer --> turn off
in shutdown, the pc and monitor is still using power, unless disconnected from the mains, much like a TV turned off via remote (uses about 5W and evidenced by the leds momentarily turning on when plugged in).

good luck on your project.

[kramer]

Thanks for the suggestions

tikbalang - a couple of points on your reply: standby and hibernate mean he same thing to me, there may be a subtle difference, all I meant was I didn't want it sitting there with the fans running constantly in a powersave type mode. I experimented with the hibernate function but for whatever reason the pc didn't reconnect to the ADSL until it detected mouse or keyboard inputs, so I abandoned that in favour of a cold boot which I would prefer anyway.
The captrick link was interesting but not quite what I'm trying to acheive.
I had considered using an external modem but as I have several obsolete internal modems and my only external modem is USB powered, I am more than reluctant to buy yet another modem, when there are are other solutions using what I have.
Lastly, the monitor doesn't need to be turned on as no one will be looking at it, but I still get to see the remote pc as though it was on ( I checked just to make sure )
I'll get there in the end,  thanks for your help

[tikbalang]

don't forget that the modem will turn the pc on whenever it gets a RING signal from anyone calling your line.