■ RoboSpinArt website
■ The Robot Group
■ First Night Austin
■ Dorkbot Austin
■ FIGURE 17. The Robot Group
with the RoboSpinArt machine at
Austin City Hall.
■ Jonathan Coulton on RoboSpinArt
■ FIGURE 19. The author
interviewed by KUT radio.
■ “RoboSpinArt — Concept to
■ “Ink jet gantry — proof of concept”
■ FIGURE 18. The press had fun
shooting the spinning colors.
could as quickly as we could trying to
make a complete second RoboSpinArt
machine from scratch. Rick made a
second set of peristaltic pumps (again
all by hand) and another spinner for
the bucket in record time. Paul
photo-etched more custom printed
circuit boards. Many other roboteers
stepped in to help with woodworking,
decorations, painting, circuit board
■ FIGURE 20. The
ink jet gantry.
■ FIGURE 21. A test logo
from the ink jet gantry.
preparation, and all the other bits
needed to finish the machine.
In the end, we only ended up
with two unrealized features: the
strobe light sync circuit and the
ink jet painting gantry. Though we
did get the ink jet gantry mounted
(Figure 20) and in preliminary
tests we could get it to print the
circular logo (Figure 21), we found we
would need a more precise motor
speed controller to make sure that
the ink jet wouldn’t underwrite or
overwrite the text due to variations in
speed of the motor that spun the
paper. The solution (a feedback
enabled motor controller) would
require us to rework the shaft
sensor to provide the feedback.
Unfortunately, it would also require a
reworking of the strobe light timing
circuit to process this new signal.
There just wasn’t time to get it done,
so the strobe effect and the ink jet
would have to wait.
For all intents and purposes, when
the day arrived, we had two fully
operational RoboSpinArt machines
(Figure 22) ready for First Night. We
set up on the day of New Year’s Eve in
front of City Hall at 10: 30 a.m. By
11:00 a.m. we had a line of people
waiting, so we fired up the machines
and started painting. We had a steady
line of folks till 11: 30 that night (Figure
23)! The machines ran non-stop (only
changing out the operators) for a full
12+ hours, going through well over
1,600 cards without a single system
failure. It was an amazing success!
Little children, older folks, parents —
everyone loved making spin art!
■ FIGURE 22. The author with two
working RoboSpinArt machines.