PCp project under construction: ongoing summary + images

teraflop122 · Post by **teraflop122** » Fri Jun 10, 2005 10:40 am

I have finally acquired all the parts I need to at least begin to build my PCp.

The parts I have:

1. 3.9" x 5.7" motherboard w/ 300Mhz Geode fanless CPU
2. 128MB PC133 SO-DIMM
3. 9.0 GB 2.5" hard drive
4. 8 D battery clips
5. 12v AC adapter
6. a cardboard box
7. Two 7805 5v voltage regulators
8. Two sliding switches
9. Logitech dual analog gamepad
10. 2.5"-->3.5" IDE cable
11. 3.5"-->2.5" IDE adapter

The parts I need:

1. PSone LCD (soon to arrive)
2. Another 7805

Planned software loadout:

1. Windows 98SE
2. SNES, Genesis, NES, SMS emulators
3. JoyToKey
4. Alpha Centauri
5. SimCity 3000
6. SimCity 2000
7. Sonic CD
8. Master of Orion 2
9. Civilization (various versions)

Construction status:

My first attempt to start the tiny motherboard failed. Turns out that, while I had a molex power source connected and routed into my Desktop, that wire was not actually plugged into the power supply. Stupid me. After that, I got it working.

Then came the next problem: the motherboard would not recognize it's hard drive. I spent most of an hour changed the arrangement of the IDE cable: the motherboard connector had 44pins, four of which were for power, but the IDE connector had only 40- it excluded the power pins- and the documentation was shoddy at best. After fiddling with it, the chances of me messing it up severely increased, and low and behold, I set the 3.5"-->2.5" adapter on fire!

The damage done:

Only then did I realize why the hard drive wasn't working: the molex connector wasn't plugged in!!! That was the second time something was either unplugged, or plugged into the wrong port, but it wouldn't be the last.

Despite the burnt adapter, it still worked! I booted Windows 98SE into the drive without trouble. Somehow the hard drive avoided death during the small fire...

Here is the setup as seen next to my monstrous desktop, which was supplying the power. The ruler is there for reference:

I went on to load the first few emulators into the computer, but I haven't any screens of those running. Basically, this is how the PCp is performing at the moment:

Genesis: (Kgen98) full speed
SNES: (Zsnes) MarioKart: practically unplayable/ scrollers: laggy/ RPG's: acceptable performance
NES: (Nesticle) Giving me a heck of a lot of trouble; the games barely run

Sonic CD: acceptable performance

Needless to say, do NOT use Geode CPU's, they simply don't have the oomph of a P3 or P2 counterpart. If you want to save power, go for a 667Mhz Eden CPU, or the more power-hungry Via C3's.

Here's just some other random pic:

I'm currently working on the power circuit that will allow the PCp to run off either batteries or an AC adapter. Both of those are 12v sources. Some of the current is dropped to 5v as well for the motherboard and hard drive via an array of parallel 7805's (to allow for greater AMP ratings). I will post a crude but effective image of the planned curcuit momentarily.

EDIT:

The power circuit:

Turbo Tax 1.0 · Post by **Turbo Tax 1.0** » Fri Jun 10, 2005 10:52 am

i hope it comes out frikin awesome and nothing goes wrong

i may have to steal it

Unidentified Assilant · Fri Jun 10, 2005 10:54 am

good luck dude! Nice work already, I'm getting jealous

:)

daguuy · Post by **daguuy** » Fri Jun 10, 2005 11:16 am

good luck, you'll need it:PCPs are more complex and difficult than portable videogames

teraflop122 · Post by **teraflop122** » Fri Jun 10, 2005 11:42 am

I here that

I just realized that I do NOT need a 12 volt line. The reason I was confused was that I had OBLY the 12 and the GND connector for a preliminary test, not the 5v and the GND. Why? Well, like many men, I seem to have a problem with colors ~_~ Meh. The 12v molex is yellow, I think, and the 5v should be red. I had the two mixed up

What does that mean for my project? It means that I only need 5 D batteries instead of eight!

Five D's yeild 7.5volts, the minimum inputs for the 7805's. 4 would yeild 6 volts, which I couldn't convert to 5 as easily, and would damage components overtime.

My power diagram will not change- accept that the hard 12v line will actually be 7.5 volts, and it will only lead to the LCD screen and the 7805's. When plugged into a wall adapter, 12v will go directly to the LCD and the 7805's as well: the LCD uses a 7805 internally, and shoulded have trouble with the 12 volts.

The PCp will not be decreased in size, however, as I have a strict time limit, and bigger is inherently easier.

EDIT:

Loading Software:

I have the Laptop drive plugged into my desktop at the moment, so I can transfer my music and some hefty ISO files (which refused to burn onto a CD-R for some reason). Strange thing is that, for every Gigabyte of data I transfer, the computer crashes

As far as I can tell, the computer is trying to send the data at 66MB/s or 133MB/s, while the laptop drive can only operate at 33MB/s, so to much data gets backed up to far...

daguuy · Post by **daguuy** » Fri Jun 10, 2005 11:50 am

psone screens have some components before the 7805s so 12v will blow it up. i heard they can't go more than 9v. a 7808 would fix that

teraflop122 · Post by **teraflop122** » Fri Jun 10, 2005 3:16 pm

Ah, yes. In that case, it would be fine running on the batteries at least, but not on the 12v wall current. In that case, I will simply have two AC jacks instead of one: a 12v 4 amp jack for the main components, and the standard screen jack for...the screen.

I have scrounged together a few tens of dollars, all of which I have used to massively upgrade the original power supply designs. The supply will now feature four(4) individually heat sinked 7805 regulators mounted to a quality prefab PCB. I may need a few more parts if I am to use the LCD's standard AC jack in conjunction with the 12v.

I plan to complete the power circuit today, and the LCD VGA mod tomorrow, depending on time limitations.

soundwave · Post by **soundwave** » Fri Jun 10, 2005 3:25 pm

Lookin' good, hope it comes out good.

teraflop122 · Post by **teraflop122** » Fri Jun 10, 2005 3:52 pm

Like I said, Input IS appreciated. If it wasn't for Daguuy, I would have become a very sad Teraflop over the next few days. I have reworked the power circuit. Luckily, I do not need to purchase any further components: I managed to isolate the ground and leads of the mobo and the LCD with just three switches. There's probably a better way of doing it, but I don't have the resources for it.

Here is the reworked power circuit:

NOTE: 12v AC and 7.5v AC actually denote the output from an AC *adapter*, not wall current.

daguuy · Post by **daguuy** » Fri Jun 10, 2005 3:58 pm

you'll need DC, not AC. to change AC to DC, you need a bridge rectifier, i'll be back in a minute to show how to make one.

teraflop122 · Post by **teraflop122** » Fri Jun 10, 2005 4:15 pm

As stated, that "12v AC" and "7.5v AC" was just my short-hand for 12vDC outputed from an AC adapter, and 7.5vDC outputed from an AC adapter.

daguuy · Post by **daguuy** » Fri Jun 10, 2005 4:34 pm

ok sorry i misread

shmagoogin77 · Post by **shmagoogin77** » Fri Jun 10, 2005 5:15 pm

frigin awesome

tom61 · Post by **tom61** » Fri Jun 10, 2005 5:34 pm

The supply will now feature four(4) individually heat sinked 7805 regulators mounted to a quality prefab PCB.

I've heard that using multiple 7805s in parallel is a bad idea. This is one of the reasons I've not made progress on mine, I have a thread in an electronics forum trying to figure out the best option for power.

http://www.hardforum.com/showthread.php?t=911379

"putting regulators in parallel will work to get more amps, but, it can cause oscillations and some other weird stuff to happen."

daguuy · Post by **daguuy** » Fri Jun 10, 2005 7:14 pm

when you put them in parrallel, one gets all the electricity until it can't handle any more and then the next one takes what's left over, etc... if you use heat sinks then i don't see ehy it wouldn't work