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The Atari 800
XE Laptop - 2005 |
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Designing and
building the laptop case...
With the Compact Flash drive working I was ready to
continue. Finally! The
first order of business was finding a screen to use. The first
noobish idea would be using an old laptop screen but that's quite
hard, if not impossible. See, the Atari puts out composite video (like
the yellow jack coming off your PS2) while a computer monitor takes RGB. On top of that most laptop displays are proprietary
digital and
therefore only work with the laptop they come in. Some people try
hooking laptop screens up to their PC's and have a really hard time
- connecting it to an Atari would be even more difficult and very expensive.
That left me
with using NTSC screens, such as the displays in a car DVD player. I
couldn't use the cheap and readily available PS1 screens because at
5" they're way to small. The thing to think about is the laptop case
is going to be the size of the motherboard at least... so you need
the biggest screen possible. Another factor is overscan. Old
computers and game systems assume rounder, smaller TV's and
therefore usually had a good deal of "border" on the edges since
they assume this to be off the edges of the viewable screen for the
most part. However modern TV's, especially LCD's, show pretty much
every bit of a video frame making this "overscan border" even more
obvious. Another strike against a small 5" screen.
A 10" laptop monitor would have been
ideal, but again impossible. Most of the cheap car DVD player
screens were 7" widescreen - also unacceptable. Finally I stumbled
across this at Radio Shack:
It's an 8" TFT
display with a bunch of extra crap built in (TV tuner, ironically
Compact Flash picture display card) The price was right, $150 after
rebate... I had 2 days to decide before the sale ended. Then a sales
associate got the manual out and I discovered this thing had
rechargeable batteries in the base!
The batteries in the base. Don't worry -
I bought the thing before I opened it ;)
$150 for a
screen PLUS (9) 2100mAH Ni-MH AA's and a built-in charger - can't
beat that. SOLD! (I did find a few dead pixels later on - oh well what can a man
do?) I bought the thing, took it home and DIDN'T immediately hack it
apart.
"What?" you
say "You, Ben, hacker of all hacks, didn't immediately open it up?
What's WRONG you with?"
I'll tell you
what's wrong! See the Atari 800 had this thing called "color
artifacting" What happened was in its high-res Graphics 8 mode
(ahem, 320x240 with 1 color) if you made vertical lines with spaces
between them they'd not appear white (or the one color available) but
rather green or magenta depending on whether the line # was even or
odd and what version Atari it was. Thus programmers used this to add color to high-res mode games
(a good example of this is Choplifter)
An emulated, non-artifacting version of
Choplifter. Notice all the vertical lines? On a real machine they
appear as solid color. Time to save some hostages.
Thing is,
emulators have to actually simulate this as it's a feature of TV's.
Therefore my concern was this modern TFT display might not have the
artifacting characteristic. So I had to test out the screen before I
opened it to make sure artifacting would work. It did, thankfully,
so THEN I ripped apart the screen!
The guts of the Axion TV.
How nice of
them to have all the crap inside this screen be modular! The LCD
portion is on the left, circuits on right. Naturally the big PCB is
the main guts, gotta have that. Below it are the TV tuner and
Compact Flash reader. Those can go bye-bye! What rubbish. What I actually ended up
doing was using the +5 volt power supply on the screen that was
intended to power the Compact Flash adapter and use it to power the
Atari instead. Why not?
A glued and taped LED inside the screen
case. Now I don't feel so bad about MY hot glue obsession.
Now that I had
my screen I could design the case of the laptop. (As I usually say,
and will say again, the screen is a huge factor in the design) My Atari
800 motherboard was currently in this condition:
The space I
had cut out for the hard drive originally just happens to also fit
(9) AA batteries. Obviously I subconsciously must have known that
back in 2003 - clearly. At the bottom of the motherboard you can see
the battery charging circuit I took from the TV, and how it goes to
the power switch on the upper left. Alright, let's get down to
construction!
The
keyboard!
As usual I
designed everything in Adobe Illustrator and cut the parts with
laser engravers and a CNC machine. I started with the keyboard,
mostly because I'd never made a keyboard before and I really wanted
to see it complete!
Above is the first step - tact switch
placement on the keyboard grid. I used small 4.5mm switches so they
could be INSIDE the keys rather than under them. This is a trick I
used for all my ultra-compact projects, such as the NES Micro.
Either my keyboard construction or the
workbench of the world's most hardcore Scrabble enthusiast.
I wanted the
keys to be nice so instead of making the text with decals I actually
raster engraved it into the surface of the black textured plastic to
create characters.
This is much slower but gives them a good physically look and feel. In the upper left
you can see the "key mesh". This is a grid I cut and laid packing
tape on the back of. Once a key was attached to its hollow base I
then placed it into the sticky grid, as shown below:
Front and rear of the key grid. Note the
holes that the tact switches fit into. So clever am I.
Next came the hard part, or rather the boring monotonous one. I had
to wire up the tact switch grid to the keyboard controller in the
same way it was in the original keyboard's circuit. See below:
You know, not as hard to wire as it
looks. Really. Or maybe I've just become numb to the process.
Note the
hole in the bottom of the keyboard - this is where I intended my
"Cursor Mushroom Button Knob" to go. In the olden days we
didn't have "mice" to move the cursor around the screen, no sir-ee!
We had to use KEYS, and sometime we'd have to press a couple keys
even! (Then walk to school barefoot uphill through the snow fighting
dinosaurs) With the Atari you had to hold "Control" then press one of the
direction keys (which are normally +, -, etc) This worked but was
clunky.
My idea was to
have a knob that you could push with your finger to "magically" make
the cursor move around the screen. Since the OS was locked the only
way to accomplish this was mechanically, and boy did I have a hard time
getting it work!
The cursor mushroom button. Yes, that IS
tinfoil you see.
The trick was
"Control" had to be pressed and held before you could hit the other
keys. My solution was to mount the knob (really just the top of a
PS2 analog stick) on a spring with 2 tinfoil-covered discs below it.
When you press the knob in any direction the first thing that
happens is the disc connect - this is wired to the "Control" key.
When you press a little harder the tact switches below click the
appropriate arrow key and the cursor moves. While it's hard for me to believe I
actually resorted to using tinfoil for something I can't deny that
it works. Seriously, I probably spent a good 12-15 hours figuring
out the best way to do this before I said "the heck with it!" and
made a trip to the
supermarket!
CHAPTER 4 - The rest of
the assembly!
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