My laptop power on solution - 56k modem port and telephone cable

**sivart321** · 05-05-2005, 05:03 PM

One way to power on a laptop that was mentioned by a few people who have done similar things was to wire into the laptop power switch and run two wires out to your momentary switch/pulsed relay switch. I heard someone mentioning hooking it up through their 56k modem port (as very few people still use it) so that it is removable. You simply plug in a 2-wire telephone cord that is in your car wired to your turn on relay circuit.

The above method is what I ended up doing. I swear I ended up with the hardest switch to solder to on my DELL Inspiron 4000. I ended up having to completely dissasemble the laptop to get to the back of the power switch PCB. But thankfully I found two small contacts to solder the wires to.

Here is what I did:

Soldered 2 wires to power switch PCB. Used a mulitmeter to test which 2 leads connected when the button was pressed.

Top view of switch PCB.

Here I ran the wires down inside the case to where the 56k modem connector/wire goes into the NIC/modem. Cut off the connector and soldered to the wires. Top view.

Bottom view showing the two 56k modem wires soldered to my two new wires. On the right is the 14pin connector that goes into the NIC.

These two pictures show the trace from the 56k modem port to its wire. Again I used the multimeter to verify that the 56k modem port did in fact go to the two wires which plugged into the NIC/modem.

**Gobby** · 05-05-2005, 05:05 PM

Thats an excellent idea to make the laptop removeable.

**eblend** · 05-05-2005, 05:22 PM

that is a very awsome idea, not like i use my 56k ever anyways , i go do this now thanks

**zPilott** · 05-05-2005, 05:47 PM

I tried to take apart the plug in mine, without any luck. so I just ran the wires out the hole.... Looks nice

**eblend** · 05-08-2005, 11:16 PM

did it on my toshiba, works like magic!

**aoLhaTer** · 05-09-2005, 03:58 AM

Pretty slick

Another option would have been to run wire outside the laptop and then terminate it with quick disconnect connectors so it can be removed if necessary
This is certainly cleaner though

**esmith13** · 05-10-2005, 10:46 PM

now what are you doing for startup and shutdown? Do you have any automation for shutdown when the power goes off in the car at all???

**sivart321** · 05-11-2005, 03:09 AM

I will be using a relay circuit from my key ignition accesory on position that will momentarily connect the two remote wires for a 1/2 second or so when the car gets turned on. That relay will also turn on the car adapter that plugs into the laptop.

I am using an application called 'hibermon' created by a guy on here that puts the computer into shutdown, standby, hubernate etc (whicever you chose) upon losing the power connection(or after a set time) . For a laptop, it will detect when it looses AC power. So for however long you set it to wait, 10 seconds, 30 seconds, etc, it will run off its battery until it sends its standby command to the computer (for example). The time delay allows for any instance where you turn the car off and lose power but would turn the car back on in a few seconds or what not. Using the laptop with this circuitry and software I have created a fairly intelligent startup shutdown controller wannabe (and tank setup using the laptop battery) for little to no cost.

**zPilott** · 05-11-2005, 10:57 AM

that is pretty much my setup too.
http://www.the12volt.com/relays/page5.asp the constant to momentary circuit is the one that I use to turn on the laptop (I had to play aroudn with the resistor, cant remember what I set it to).

Af for the shutdown, you can use the built in windows power settings, but in my experience they are unreliable, as applications can keep your computer from hibernating automatically.

I created a little vbscipt that runs in the background and detects power changes and then does stuff (including hibernating after 30 seconds). One of these days I might turn it into a real application .