TABLE TALK: (counterclockwise from top left) LEDs’
positive leads soldered in rows, fiber-optic cables
aligned in foamcore, the two tables on display at the
ITP Winter Show at N YU, testing the interface.
To pour the concrete, we built a wooden form using
1× 8 lumber screwed into plywood. We used caulk to
form a seal and sprayed the inside of the form with
cooking spray so the concrete wouldn’t stick. We
used Buddy Rhodes Concrete Counter Mix because
of its small aggregate (we didn’t want large pieces of
stone pushing the components off the grid).
We mixed the concrete to oatmeal consistency in
a plastic bucket and spooned it into the mold. We
were very careful to avoid disturbing the wires and
the fibers. Once we had a good amount of concrete
in the form, we whacked it with a rubber mallet from
below for about 15 minutes to get the air bubbles
out. We covered it in plastic and let it cure for 24
hours, then loosened the form and let the sides dry
for another 24 hours before removing the form. Now
we had a concrete block attached to a foam block.
The fun part is getting the foam off the concrete.
It involves a lot of pulling and a bit of a mess. The
basic idea is to get as much foam off in chunks as
large as possible without breaking the wires.
After the foam was off, we plugged each of the
fiber optic cables into the holes of the plexiglass. We
used a flashlight to shine a light from the front of the
concrete into one fiber at a time, allowing us to see
where in the plexiglass grid it went. Fortunately, we
had bunched the fibers into groups earlier, making
the process go much faster. If we’d had to find individual fibers from a huge bundle we would have driven
ourselves crazy. The fiber ends that poked through
were trimmed flush to the surface of the plexiglass,
so they’d be able to mate to the LED plate.
We made a stand for the block out of medium-density fiberboard, then we covered the MDF with
kraft paper and shoved everything into the cabinet.
After writing and debugging the code to control the
LEDs, we were done.
Imagine one of these blocks on the beach in
L.A. and the other on a sidewalk in Times Square.
People could communicate between the two cities.
It could also be installed in a kitchen, or anywhere at
home. Pushing further, you could make these tables
act as drawing tablets — tracing your finger on one
would light up the other, following the drawing on
the first one.
More images and info: setinstone.wordpress.com
Ithai Benjamin and Vikram Tank are completing their graduate
studies at N YU’s Interactive Telecommunications Program.
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