DigiComp (was Re: how many computers?)

From: Ethan Dicks <erd_at_infinet.com>
Date: Wed Jul 15 06:58:11 1998

Re: DigiComp

People who's names are lost to time wrote:
> >>Way cool. I had access to one in high school, to play with, but I never
> >>owned one. I've written to Edmund Scientific. They get the occasional
> >>letter inquiring about the DigiComp 1, but so far, not enough interest
> >>to resurrect the product.

> >I have a set of documentation for it (sent to me by someone a few years
> >ago) and I would LOVE to get one for my collection...

Docs are available at http://galena.tjs.org/digicomp/

> Sounds like you had fun!
> The picture in the Edmund catalog looked like it was made from various
> colored shapes of flat plastic. I know it wouldn't be quite the same, but if
> you have the documentation and once had your hands on one, could you
> recreate it from mat board and an exacto knife? Or some plastic as required.
> That's the kind of thing
> I might do...
> -Dave

It's molded plastic, but not quite as simple as cut sheet. Also, the
clocking is propagated by bent metal rods. I remember having to fashion
a replacement rod that resembled a squared-off question mark (lower right
side of rear view on page 3 (http://galena.tjs.org/digicomp/p4.gif))

I suppose that if you had one example of all the parts, you could
manufacture replacements, but having used one myself, the tolerances
would have to be in the vicinity of one or two 18 gauge wire diameters
or else the logic would be too sloppy. If I were going to build one
for myself from scratch, I'd probably try to make one out of aluminum
and grease it with graphite. I don't know if anybody out there has
every worked with die-cut cardboard, but it might be possible to set
up a jig to stamp them out of thick (~1 mm) fine-grained shirt cardboard.

To make a die-cut jig, you stick strategically placed razor blades in
a block of hardwood, and at the corners, you glue down small (~1 cm2)
foam pads to help clear the product out when you release the pressure.
It would be easy to check for tolerance - the real plastic part should
fit neatly into the outline, but not fall down between the blades (resting
just inside the cutting edge) I don't guarantee weeks and weeks of
use with a cardboard DigiComp unless you soak at least the clock end
in some sort of epoxy or adhesive to plasticise it.

I, however, do not have a DigiComp to replicate. Anybody else?

Disclaimer: I'm not a mechanical engineer, just an amateur woodworker. Take
these hints and observation as the free advice they are.

-ethan
Received on Wed Jul 15 1998 - 06:58:11 BST

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