Maker
on a milling machine? Injection molding? Duplicates
cast from polyurethane or pourable plastic? Quotes
were submitted, prototypes alluded to.
One writer enthused, “We need to form a corporation and elect a leader and set up a purser.” But in
each case, the vision of creating a workable product
via email collaboration faded. Six years after the
group’s formation, the only way to get your hands on
a Digi-Comp was to buy one on eBay for about $150.
Forget that. I had to find out how this mechanical
computer worked.
Fortunately, the group’s
archives included
detailed photos. Several
knife blades later, with a
somewhat shaky mat-board prototype in front
of me, it was time for a
test drive. At the heart of the mechanism were DrawPlus, from the U.K.-based company Serif, let
three horizontal flip-flops attached to the binary me design the vector shapes on one layer and the
readout. Vertical rods established a link between print wraps on another in registration. Color laser
input and output. “Programming” Digi-Comp meant printing had its own pitfalls: not many low-volume
attaching small tubes to I/O tabs along the flip-flops. print shops handle 12x18 jobs; fewer still can guar-My simple test routine used only four tubes, which antee a flawless cherry red on glossy stock! And
toggled a readout digit between 0 and 1 each time I there was still the matter of gluing the wraps to
actuated a clock cycle by moving a small crank. the boards prior to die-cutting.
And the gizmo worked! Yet, even having built it, One recurring question was whether to outsource
figuring out exactly how it worked was a challenge. a component and produce it myself, or pass it along
Here was an ingenious toy (technically a “mechanical to the end user with detailed instructions. How
programmable logic array”) that had lost none of much time would users want to invest? For example,
its teaching potential. It deserved a new lease on life. could they be expected to bend their own wire rods?
But simply providing a set of plans wasn’t the Maybe, but with what tool and what results? Quality
way to go. Building the prototype convinced me could suffer. How much would a wireforming shop
that no handheld craft knife could shape all these charge for a measly 1,200 rods? Ouch! Fallback:
little tabs, slits, and nubbins precisely enough. It Design a jig and pay my son to crank ’em out.
was also way too flimsy; the board thickness would At every turn, I had lots to learn about materials
need to double. I began to consider a kit-based and processes I’d initially assumed were no-brainers.
approach where I would be the “maker in the middle”: As for steel rule die-cutting, most of my education
fabricating the tricky bits; shipping out a package was over the phone, from guys who occasionally
of subassemblies, loose parts, and instructions; tossed me a technical tidbit while explaining why
and letting the end user finish the job. I resolved to my job was impossible.
produce a kit with precision die-cut pieces supplied In hindsight, there were other questions I probably
as prepunched sheets; users could press the parts should have asked myself. How much of my own
out and then assemble them. time ends up invested in this? Ultimately, is there any
So began a nonstop, seven-month solo voyage payoff? As a fellow DIY-er, though, you’ll understand:
toward “git ’er done.” Each component entailed I must be missing the gene that lets such trivial
Q-and-A loops, vendor sourcing, and time-and-labor questions keep me awake nights.
calculations. First, I tested cardboard stock for
strength, density, grain, and warp. Eventually, I
settled on 80-point binder’s board, the stuff used
for hardcover books. Next, I had to determine what
scale I was going to work at. That would depend on
package constraints, which meant planning from
the outside in. Online, I discovered gusseted stay-flat
mailers: unadorned, practical, 9x12 envelopes. If we
die-cut the pieces on a 12"x18" layout, then sliced
that down the middle, could we cram sheets, parts,
and a 50-page manual into a 9x12 mailer?
Visually, the pieces had to look great, with snap
and gloss, legible labeling, and a retro gestalt.
Here was an ingenious toy that had
lost none of its teaching potential.
It deserved a new lease on life.
Tim Walker’s Digi-Comp I v2.0 kit can be read about and
purchased at
mindsontoys.com/kits.htm.
