Thread: Laptop Auto Power-On / Turn-On Module

if you already have a carnetix, then i would use its "button press" output to activate a couple relays to simulate the button presses. just make sure you use small relays like this project does so you don't over load the cnx.

basically have the cnx provide momentary ground for 3 relays, each of which will simulate the power buttons of your laptop, hard disk and usb hub (your hub has a power button?).

Originally Posted by Startingline13

I'm not quite sure what you mean about "activate a couple relays to simulate the button presses. just make sure you use small relays like this project does so you don't over load the cnx."

When it comes to Relays, or things of that nature, I'm almost clueless.

No, my USB hub does not have a power button, but I use the 5V output from the carnetix to power it. As soon as the computer is turned out, the USB hub will provide power to other accessories (ex. charging my blackberry), but without the computer on the USB hub will NOT power any devices, even though it is powered by the carnetix. I guess the USB input from the pc is what tells it to turn on.

Finally Gibson, I have a question about my power inverter. I have basically the same one (almost identical I believe) as your first camry build. Is there any way to create a device which will turn that inverter on each time I turn the car on? Otherwise as it is, I need to reach behind my seat and hit the switch every time I start the car to provide power to the laptop when the laptop battery runs dry.

sounds like all you need are two relays. one will need to be an automotive type and the other a smaller one.

http://electronics.howstuffworks.com/relay.htm

search around - i'm sure someone has pics and/or schematics on here... relays are a basic thing that nearly everyone here uses.

for my inverter, used a standard automotive 30 amp relay. i had one of the coil pins of the relay going to the hot side of the cigarette lighter wiring and the other pin to ground. the switched side of the relay closes the circuit for the (+) wire of the inverter. this way, i just leave the inverter's power switch on all the time, and whenever my lighter is live (any time car is on) the relay is on and therefore so is my inverter. turn the car off, relay and inverter turn off. cake.

for the cnx side of things, i suggest using a relay to isolate the carnetix from your laptop's power button - there's no telling what would happen if you shorted one of the button contacts to chassis ground. instead, use the CNX's momentary ground to activate the relay. ie: have one wire from the battery go to one side of the relay's coil, and the other side of the coil goes to the cnx's "power button/acpi" output. then the two contacts of the switch side of the relay go to your laptop's power button.

Originally Posted by Startingline13

Gibson, you've been more than helpful, thank you for everything.

I have my inverter connected the same way - from the cigarette lighter in the front of the car. So in regards to my 30 amp relay from my lighter socket to the inverter, is this what I would be looking for: http://www.amazon.com/30-Amp-Relay-w.../dp/B000Z6S3WG

I kind of lost you with the "use the CNX's momentary ground to activate the relay. ie: have one wire from the battery go to one side of the relay's coil, and the other side of the coil goes to the cnx's "power button/acpi" output. then the two contacts of the switch side of the relay go to your laptop's power button."

By battery, you mean the laptop? (I actually use a distro block for all of my 12v)
I've included a ghetto photoshop drawing to help myself understand, but I definitely did something wrong between the relay coil and the laptop.

by battery, i mean the vehicle's battery. the laptop battery doesn't give us power all the time and isn't convenient to hook into.

Originally Posted by Baritono

Hello,

I have been working on building a carputer using my laptop. Thank you for all the great info. I have built the controller using the schematics from the first page. When the laptop is on standby it always works 100%. But when the laptop is on hibernate it will take two tries for it to come up. I have connected the controller to a cigarette lighter in the car, which receives power when the car is on-key fob is in the ON position. Does anyone know if I would need a different capacitor/resistor combination? I noticed that in the W3BMA5T3R instructions linked from the first page a similar schematics plan includes a diode that is not included on the initial plan found on the first page. Would that make a difference?

I appreciate any help and Happy New Year!

i'd suggest giving a turn-on signal to the controller from somewhere other than the lighter. the reason for this is that while you turn the key from OFF to START, it gets a momentary blip of power as you pass ACC and ON, but then turns off while in START then comes back again when you release the key and it rests in ON. this could be "freaking out" the laptop. i would recommend hooking into the car's keyswitch itself - find the wire that's hot while in ON and in START so that the controller won't get that little blip and potentially provide 2 button presses.