Thread: Laptop automatic startup using a single shot relay

I have been looking for a way to do this as well, however i dont think a "wake on" option would be the best idea, seems complex, what about maybe just simply having some kind of circuit that would jump the switch on the laptop directly?

Im not sure how to solve this with out modification.

Jesse

Originally Posted by jonee

I've been looking for an automated way to startup my laptop upon ignition.
I didn't like the idea of having to push a button manually.

Therefore I thought of this solution which is a combination between wake on link (modem) and a single shot relay (http://controlsupply.com/a4121.htm).

Would it be possible if I would wire the ignition simply to my DC-DC laptop converter, and let the s-s relay 'sense' current on the same wire and pulse the single 'wake on link' signal to the modem?

its a pulse relay. It will dot he job you want yeah. they you set the PC to standy or hibernate after so many minutes after AC is turned off.

There is quite along thread about ti somewhere...
Remote laptop startup
there is a circuit to build your own pulse relay there witha couple of components and some otehr stuff.

Jesse, As for the startup: I can't use the "pulse relay" to pulse the power button because, when the ignition is on and the laptop is working, it is possible that the ignition is switched off for a few secs/minutes and then restarted (eg after filling up at the gas station).
At that time the laptop will probably still be running, so when the car 'ignites' it will send a pulse to the power button, meaning to send the laptop to standby/hibernate.

I don't think that if the laptop is on and it receives a wake on ring/modem, that anything will happen, and that's what is supposed to happen.

Scouse, thanks for the link.

What about telling windows to do nothing when the power button is pressed. That way the pulse will work when the laptop is hibernating, but if windows is running it shouldn't do anything if you stop for a short time. (Depending on what you have the hibernation time set when running on battery)

Originally Posted by McFreak

What about telling windows to do nothing when the power button is pressed. That way the pulse will work when the laptop is hibernating, but if windows is running it shouldn't do anything if you stop for a short time. (Depending on what you have the hibernation time set when running on battery)

wow, that is much better than what i did. i ended up using a 5v relay hooked up to a usb port to only allow 12v into the pulse relay if the computer was not powered on. i was concerned about the 5v relay burning up because of the 12v running through it... i like your way much better. time to make a change.

What about telling windows to do nothing when the power button is pressed. That way the pulse will work when the laptop is hibernating, but if windows is running it shouldn't do anything if you stop for a short time. (Depending on what you have the hibernation time set when running on battery)

Well, that would work once windows is up and running, but have you tried pushing the power button before windows is loaded? Eg 5 seconds after booting. My laptop shuts down immediately in that case.

But maybe there might be a solution if we could 'tell' the pulse relay that after a pulse, it shouldn't pulse again for let's say 20 secs.
Anyone know of such a pulse relay?

I would like to do something similar, but with my xbox. I could use the single shot relay to "Push the button" but i would like it to "push the button" again when the remote power is lost. Im not worried about it turning off the xbox when i turn the car off and back on or whatever. pretty much what i want is...

car turns on --> relay switches because of remote wire --> xbox turns on
car turns off --> remote power lost relay pushes switch --> xbox turns off

can anyone help, this is all i need to finish my project.

I am just now implementing a system for starting up my laptop using a small 555 timer circuit. I'll post up the schematic in a little bit. Basically, I have it monitor the 5V on one of the USB ports (which is only on when the PC is running), and if it is NOT on, it pulses a relay, wired to the power button. It worked on the bench, just gotta give it a shot in the real deal.

Here's the schematic of what I'm working on. Basically, the 555 timer is continually cycling. (about 3 seconds on, 1 second off). When it is on, it turns on Q1, which pulls down the voltage after R4, turning off the relay. When it is off, and if Q2 is also off, the voltage will raise, causing the relay to pick up, and press the power button on the laptop. Once the computer is on, the USB5V will keep Q2 turned on, so it will not energize the relay anymore.
This was a quick and dirty solution, using parts I had. I've seen others using microcontrollers and such, but this seems to work just fine for me. I was going to use a Phototransistor or Otpoisolator off the power on led, but the USB 5V seems a much more reliable method.