On 2010-01-27, Frnak McKenney wrote:
On 26 Jan 2010 06:31:04 GMT, DoN. Nichols wrote:
[ ... ]
O.K. My parents did have any test equipment at all -- and only
a couple of tiny claw hammers with one claw broken off each. :-)
(I'll assume that was a "didn't".)
You are correct. My fingers were apparently lazy. (And, of
course, the spelling checker could not detect that as an error. :-)
So you had to carry all your projects to the local TV repair shop,
six miles through the snow and uphill both ways? grin!
Yep! Or assemble my own stuff from kits.
[ ... ]
[...]
All wiyht. Rho sritched mg kegtops awound?
Hmm ... a reminder of another useful habit of the geek/scrounger
type. When dealing with rebooting everything, I had to lift the
keyboard for the firewall down from the top of the rack, and it disloged
a Cenco "Lab Jack" which fell corner first on the Sun keyboard which
switches between the Mac Mini and the Sun Fire 280R (Rack mount server
version of the Sun Blade 1000/2000).
Ouch!
I know the feeling. I think I need to build a robot that is smart
enough to move my cup of tea a second or two _before_ my forearm
knocks it over onto my desk. (Did you notice the 10-minute gap in
my typing? grin!)
:-)
... It totally destroyed the keycap
for "Page Down" -- so I went to the peanut can full of keycaps from
another keyboard of the same construction, and a bit of digging through
found the proper replacement key cap. Just a bit lighter in color. :-)
Luckily, the keyswitch below it survived, and it was just the key cap.
I've had to disassemble some of these keyboards and take the flexible
printed circuits and other parts down to the shop and use compressed air
to remove the accumulation of cat hair which had worked between the
layers.
So you were able to finally justify the twenty-odd keyboards in
various states of disrepair that had been cluttering up your
basement for the past ten years? (Sorry -- thinking about my own
basement, not yours. grin!)
Well ... I probably have that many keyboards (mostly Sun)
scattered around -- dating back to the one for the Sun 2/120 Two changes
of interface connector back. :-)
But when one keyboard got damaged by an Exabyte EZ-17 tape
jukebox falling on my head and then to one of the mail server's
keyboards (sticking out a bit from the bottom of the server rack), it
broke the frame among other things, so I popped off and saved all the
surviving keycaps, since I sometimes find keyboards at hamfests with a
keycap or two missing. They all (except for the spacebar) fit in a
single Peanuts can. I've had to use these a few times since. (The
keyboard was a fairly recent style -- available both in Sun's DIN
connector interface and in USB, so being able to keep these going is
nice.
But seriously... if you're interested in an overpriced and
generally impractical solution to your Damaged Keytop Problem, a
solution that would suck up _hours_ of your time, check out the
latest issue of "Make" magazine (v21, January 2010); its theme is
"Your Desktop Factory: 3D Manufacturing at Home".
Here's what you would do:
1) Build the SplineScan "DIY 3D Scanner" from p.54
2) Find an indentically-shaped keytop. If it's a specially-shaped
Enter key, glue and sand the broken one; if you can't find all
the pieces, patch it with wax or plaster.
3) Scan the keytop.
4) Use the scanned model to create a 3D model.
5) Create a replacement keytop using a 3D plotter like the
mis-named "CupCake CNC" device from MakerBot described on p.46,
or one of a number of similar gadgets described on assorted 'web
sites.
6) Sand, drill, letter, and paint the result.
I agree that it is what we *should* do -- but there is one thing
left out of that approach which I consider important. The Sun keyboards
have two-shot molded keycaps -- in which a different color of plastic
lines the underside of the keycap, and protrudes through to make the
visible marking. Painted (or silkscreened) lettering wears off rather
quickly, as I have seen on some cheap PC keyboards. (One reason why I
am using a Sun keyboard on my Mac Mini as well.)
But here's the "leverage" part: if you post your 3D model on a
publicly accessible site, the next person with a broken Sun keyboard
can skip steps 1-4, since he only has to download your model.
If you think about it, this is a marvelous way for manufacturers to
save on parts inventory, the ultimate JIT method for keeping a huge
number of plastic parts readily available for decades (or even
centuries -- "You, Too Can Build Your Own 2059 Edsel!"). The only
ongoing expenses are the 3D printer, "toner", a stack of read-only
32Gb SD chips, and someone to do the lookup and kick off the machine
as required.
Hmm ... make a jukebox for the SD chips so it can select the
proper one automatically? And make them micro-SD chips to make the
storage density even higher. Since each chip could have an identifier
in a standard file -- you could even just ship a handful of chips, dump
them in, and let the computer sort them and store them in the proper
place. :-)
Oh, and someone to collect the money. grin!
:-)
Seriously, I realise that you can't cost-justify such a setup to
replace one broken keytop, any more than you can justify building
even a 78RPM phonograph disc cutter and a playback unit simply to
make a permanent copy of your child's first word, even if it's
something as world-shattering as "photosynthesis". But... record a
thousand songs and make it possible for others to listen to music
whenever they want, and you've created an entire industry.
Actually -- I am planing to make a Edison Cylinder playback
machine using a low-speed servo motor.
You should be able to pick up a copy of Make v21 at Borders or
Barnes&Noble, or check their 'web site at www.makezine.com.
I'll keep an eye open for that.
* * *
Jumping back to long-snipped digression in this thread, a discussion
which might even have been with you -- pencil-drawn resistors -- the
other day I stumbled on a DIY project called "DrawDIO!" that
actually _uses_ this effect as a part of yet another re-invention of
the Theremin:
http://www.ladyada.net/make/drawdio/
The circuit is, like most really good ideas, simple enough once you
know the secret: a 555 multivibrator controlled by pencil-drawn
lines. What I found most impressive was the number of different ways
people had found to _use_ the device. I think someone earlier in
this thread felt that creativity required manual dexterity; see if
you agree after viewing the video clips showing the DrawDIO off.
Interesting. I remember building an array of oscillators using
CMOS gates as driving elements, and a high valued resistor and a trimmer
capacitor as tuning elements. The major problem was that it was not
stable with temperature. I wonder whether using low TC mica capacitors
and hand-drawn resistors would produce something more stable. (I didn't
use trimmer resistors because I had a lot of the trimmer capacitors from
a surplus deal, but not enough trimmer resistors -- and that many would
have been *expensive*. :-)
Enjoy,
DoN.
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