Downside to using a laptop as a carpc ?

elmerfud · 10-23-2009, 11:28 AM

I am wondering what the downside of using a laptop as a car PC is.

What if I bought a 12 inch laptop and separated the LCD from the rest of the laptop, added a touch sensor and embedded it in my dash. I could then mount the rest of the laptop wherever I wanted.

How many wires would it take to connect a laptop display to the rest of it ?

Advantages:

- very small form factor. About 8x12x1 inch thick.
- inexpensive. Some netbooks with nice 12 inch displays sell for less than $400 and have everything one needs for a car pc. Full on laptops aren't much more.

Very hard to buy a board + power supply + case + RAM + harddrive+ display for that and still have to deal with the packaging headaches.

- low power consumption. Some will run directly on 12VDC. Could use an AC Inverter too.
- built in power supply, wifi, bluetooth, sound card, keyboard, display, hard drive, etc. Its all there.
- lots of expansion via the USB bus.
- built in cooling, good on most laptops
- decent built in screen, especially with a touch sensor and glare screen added
- laptop display is nicely framed, almost ready for mounting
- easily removed to take into the house for doing routine maintenance. Run with an external monitor.
- built in ability to drive a second monitor for backseat video

Disadvantages:

- changes laptops requires embedding a different display in your dash. If one is careful, one should be able to put the laptop back to being a laptop when you are done.
- ?

Thanks

malcom2073 · 10-23-2009, 12:00 PM

My Dell laptop (for instance) has about 20 wires connecting the screen to the rest of the computer, and usually you can't extend them more than a couple inches without it failing from interference. You will also need a DC to DC power supply to run it, since even the ones that run on 12vdc run on regulated 12v, and plugging in regular car power to it will likely ruin it. There are a good number of people here on the forums that use laptops with an external monitor though, so it is possible. Personally I prefer the PC route. An all-in-one atom like the mocoso 4th gen would cost you about the same since you'd still have to get a monitor, and with the PC you'd already have a DC-DC psu with a built in smart controller.

elmerfud · 10-23-2009, 12:21 PM

They feed 20 wires through the hinges ? That changes everything. What signals are they sending ? I thought the video controller would be mounted on the laptop motherboard and the wires going to the LCD would be similar to a VGA connector.

One problem I am having with trying to use a stand alone PC is finding a good suitable monitor to use. Suitable = 12 inches or less, preferably widescreen. They aren't made in volume anymore and one is generally getting an inferior display if you buy a stand alone of that size.

One could always power the laptop via an AC inverter powering the laptop brick. Its not the most efficient way, but it would work. I was going to install an inverter in my truck anyway.

elmerfud · 10-23-2009, 12:43 PM

Here is the disassembly routine for the Dell Mini 10:

http://support.dell.com/support/edoc....htm#wp1109848

Here is another one:
http://support.dell.com/support/edoc...ay.htm#1084976

Doesn't look too bad for these models.

coreyspeed · 10-23-2009, 12:53 PM

laptop screens consit of around 20 wires for the signal and around 5 wires for the backlight, the interface they use is know as LVDS

Bugbyte · 10-23-2009, 01:37 PM

Startup and shutdown will be your issues. You'll need to hack the laptop to take car on/off signals from some source. Usually that source is a DC-DC intelligent power supply like a Carnetix 2140 that can supply the laptop with the power it needs (is it more than 12 volts? Many are.)

The laptop screen isn't touchscreen but that's not necessarily a showstopper.

Also, the brightness of the screen may or may not be a problem.

There's a thread in the FAQ emporium where someone extended an LVDS screen successfully several years ago and explained how they did it. It's possible.

boelle · 10-23-2009, 01:55 PM

i was close to getting my medion pc in the car.... then the fan started to die (solid bronze bearing)... and i wondered that it could replace the complete fan/cooling unit but the one i have now only lasted 1 year...

i surely did not want to do that so i got an mini itx board along with a case and ram plus hardrive... the whole thing not taking more space than 10 packs of smokes

for the laptop i did manage to find an LVDS to vga converter... so in the end the screen would be made and flat screen for my girlfriends pc using a VGA to LVDS converter...

but in the end i think a laptop i to sensetive for a car...

elmerfud · 10-23-2009, 02:19 PM

LVDS is designed for distances of up to 10m in noisy environments.

http://www.interfacebus.com/Design_Connector_LVDS.html

That doesn't seem like a show stopper to me.

elmerfud · 10-23-2009, 02:23 PM

One can add a touchscreen interface to a laptop display.

The reason I like laptops is that their displays are the right size and they are generally brighter than desktop displays.

Turning a laptop off is not a problem. Software will do that. I wonder if laptops can be set to start up via their Ethernet interface ? One could always just do a "Suspend to Hard Drive" and keep it powered up even when the vehicle is off. It wouldn't draw that much current. Will USB wake up a sleeping laptop ?

sargeants · 10-23-2009, 02:30 PM

12inch laptop installs are fun....ask me how I know.
for my install I had to extend 48 wires, though that was also including the active digitizer from the tablet.

It is possible, and can work out nicely if you've got the space for the 12"er in your car

Bugbyte · 10-23-2009, 03:48 PM

Quote: Originally Posted by elmerfud

Turning a laptop off is not a problem. Software will do that. I wonder if laptops can be set to start up via their Ethernet interface ? One could always just do a "Suspend to Hard Drive" and keep it powered up even when the vehicle is off. It wouldn't draw that much current. Will USB wake up a sleeping laptop ?

Search on 'magic packet' for startup info. You can wake a sleeping laptop by simply connecting a router to it and having the router power up when the car starts.

There is also something called wake on link that some machines have but I'm not real clear ont the difference.

Check the specs on the screen for the laptop. Standard car PC screens are in the 400 nit range. If the laptop is similar, you'll have similar performance.

elmerfud · 10-23-2009, 07:40 PM

Quote: Originally Posted by sargeants

12inch laptop installs are fun....ask me how I know.
for my install I had to extend 48 wires, though that was also including the active digitizer from the tablet.

It is possible, and can work out nicely if you've got the space for the 12"er in your car

How many of those wires were for the display and backlight alone ?

hexxamillion · 10-23-2009, 10:30 PM

I used an EEEPC for my CarPC. The only issue was the startup which I performed an internal mod for an external switch. I used an external VGA monitor. Other than that I can't say there is a downside because using a laptop also provides some ultimate mobility.

For example, this past summer I took a road trip listening to music with my EEEPC CarPC then when we got the hotel, the EEEPC was easily removed from the car to play movies (.avi) in the hotel. I connected it to the Hotel TV with a VGA to TV converter.

That's what's great about our CarPC projects because although they have similar goals, they are accomplished in many diverse and unique ways that fit each person's situation or environment. I can't really say laptops are no good for CarPC because you may have a different goal or situation than others.

GizmoQ · 10-24-2009, 12:57 AM

Quote: Originally Posted by hexxamillion

That's what's great about our CarPC projects because although they have similar goals, they are accomplished in many diverse and unique ways that fit each person's situation or environment. I can't really say laptops are no good for CarPC because you may have a different goal or situation than others.

Well said!

sargeants · 10-24-2009, 10:23 AM

I'll agree with that Hex. Everyone has different ideas and goals.

Elmerfud - my mistake, it was 15 wires for the screen, 7 for the inverter and another 8(or so) for the digitizer(didn't have this info in my spreadsheet, and some of those were doubled up as grounds)
I guess what I was remembering is 48 ends to connect together. Seemed like it took forever.

I like having the base of my laptop tucked behind the glovebox out of the way.

The trickiest part I found was the power, cause if you're going with a Dell or HP with those 'smart' adapters, you've got to use an auto adapter. At least with the HP if you don't the machine runs like a 286. It needs that smart pin signal to work properly. I'm using a CNX1900 to shoot 18v to the auto adapter (accepts 7-24vdc) which then gives me the 18.5 with the smart signal.

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