# Building a portable pc...



## gotrootdude (Feb 19, 2003)

OK, I'm making the $100 laptop a reality..

Here's what I've done so far..

I've got one of these micro boards: http://www.matsonic.com/new/productsdata/mscle266-f.htm
For $50

I got a PSone screen I've modded to accept vga with a homemade sync convertor: The screen was $25 off ebay.. A pic of the pcb for the sync convertor is attached.

I got a compactflash to ide adaptor off ebay for $5..

So: 50 + 25 + 5 = $80..

I'm using a spare compactflash card from my camera.. Loading it with windows as I type..

I'm also using a old PS2 keyboard: http://www.cartft.com/catalog/il/478 
pic attached:

and for now, a old power supply out a dumped PC..

I've planned on building a box out of some old scrap backing off a cheap piece of furniture.

Here's the problem I've run into.. I'd like to make the thing run off a battery pack instead of a normal power supply.. The power supply is by far the bulkiest component. How can I wire a pack of rechargeable batteries to power the board and the PSone LCD.. The PSone screen requires 7.5V, and I've no idea of how to wire to the atx pin connector on the board, or what voltages are required.. Anyone?


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## Jedi_Master (Mar 13, 2002)

Howdy gotrootdude...

Interesting project...

For the ATX voltage pinouts go here...

http://xtronics.com/reference/atx_pinout.htm

You will have to make several voltage dividers to get the correct voltage for each of the voltages required for the motherboard and LCD...

You can see in the below link what a voltage divider does, and how to create one...

http://www.play-hookey.com/dc_theory/voltage_divider.html

One thing I would be concerned with this project, is the amount of current available with the batteries...

Good luck with your project...

My electronics formulas are a bit rusty in figuring out the resistors needed, and the ammount of voltage and current required ( it's been about 15 years since VOTECH, and I've never had to use the formulas since  )...


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## gotrootdude (Feb 19, 2003)

I got the portable PC running XPsp2 off a 5gb compactflash card with 8 AAA NiCd batteries wired in series, but I ran into a problem. For some reason, the machine refuses to install certain updates, such as dotnet. Even if I try installing the redistributable, halfware through it says to insert the disk for the dotnet redistributable.

Anyone understand why? I think it has something to do with booting from a compactflash. If so, I'll image the drive to a spare hard disk and install from there, then image back to the compactflash.

Still haven't made the Sync generator for using the PS1 screen, but I've got the carbide drill bits, the double sided copper clad, the etchant, and the electronics, I just need to get off my backside and do it.

I'm using this power supply to convert the 12V from the batteries, if anyone wants to duplicate my efforts.
http://www.mini-box.com/s.nl/sc.8/category.13/it.A/id.417/.f

The Compactflash is a Seagate ST1 5gb, works in true IDE mode. XP installs and boots fine, but you have to disable the paging file on the first boot to avoid problems.


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## Rockn (Jul 29, 2001)

How long can the thing stay running on battery with all the current that the components draw? I was wondering how a microdrive would work, just need a different IDE adapter. Interesting project to be sure.


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## gotrootdude (Feb 19, 2003)

The current used is between 15W idle to 30W, for the motherboard itself, the biggest power drainer is the LCD, but since I haven't gotten around to soldering the sync circuit for the LCD yet, I'm not really sure how long it will last on just batteries. Since it's a project I only get to work on for a few hours at a time, I do know that the motherboard running by itself with the microdrive last at least a few hours. Probably could get it running all day using a portable automotive battery charger thing like the automotive part stores sell for around $30. I'll probably end up building another battery pack for the LCD, since it requires different voltage and it's easier just to wire batteries in series to get the voltage instead of building circuitry for it.


The biggest problem I've found with the microdrive, is that it's quite a bit slower when loading windows, more expensive than a laptop drive (I got this 5gig from compgeeks for $94), and that some updates don't want to install using it (it's definately the microdrive that's preventing the updates, if I clone the drive to another drive, the updates install fine).


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## gotrootdude (Feb 19, 2003)

Since this project gave me so much experience, I now plan on purchasing a few EPIA-M10000 motherboards and building car PC's for my relatives for next year's Xmas. But, I will use laptop drives instead of microdrives, microdrives are to much hassle.


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## NitroNic (Oct 19, 2003)

Just out of curiosity... do you have any instructios on how to make the PS ONe LCD accept VGA signal? I had tried some instructions out that I found several months ago... and I Couldn't every quite make it work; the stuff would show up, but it would either be slowly "scrolling" up and down, or the whole image would be skewed. SOmetimes both.


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## gotrootdude (Feb 19, 2003)

http://www.bit-tech.net/modding/2004/07/07/psone_lcd/1.html

If you want to use a vid card that doesn't have sync on green, then you'll have to either place a resistor in between the sync signal and the green signal on the VGA connector (play with the resistance to obtain the best sync, maybe a rheostat would work better) , or build a sync generator circuit.

The pcb for the sync generator circuit is in the pictures in the top of the thread, just resize, then print just the red for one side of the board, just the green (and reverse the printing) for the other size. Make sure you leave alignment marks.

I use this method for making pcb boards.
http://www.fullnet.com/u/tomg/gooteepc.htm

The electronics came from www.mouser.com

The copper clad boards are from radio shack, and I'm using diluted muriatic acid for etching.


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## gotrootdude (Feb 19, 2003)

Yeah! The drill press accessory for my dremel came today. (found it over at Outdoor Outfitters) I can finally drill the holes in the pcb for the sync generator without too much fear of breaking my pcb drill bits.

Last part, the monitor (PS1 screen) is getting ready for hookup. 

The screen is supposed to run at 7.5 volts DC, but I think it may accept 7 volts, so I'm going to try to run it using this: http://www.cpemma.co.uk/7volt.html

I've also got to rewire my Morex power kit, I left it on the floor at the office and the owner's dog decided to chew on two of the wires.


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## xavier (Oct 2, 2003)

Your project sounds much like one of my oun. Im bulding a portable pc using a old car amp as the case to mount in mt truck as a way around buying an ipod


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## cheese (Jun 22, 2003)

Your a crazy man gotrootdude, cant wait to see how she turns out.


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