Daniel wiring up the speed controller and battery charger.
Oscar disassembling the wheelchair battery charger.
Assembly of frame and test fitting of legs.
54 SERVO 11.2009
San Jose State Unversity in California. As part of our
undergraduate program, we were required to design and
manufacture ... something. The project was quite open-ended and there were numerous faculty-supported projects
to choose from, but I didn’t like any of them. So, I came up
with a crazy idea ... What if one could build a big mechanical
spider like the one in Wild Wild West without using modern
technology? Could it be done? How would you do it?
So with a vague idea in mind, I managed to convince a
few friends that I was not insane and we embarked on a
fantastic journey to the blunt edge of low technology.
We were just five regular guys. We didn’t have a huge
amount of faculty support behind us. While other large
teams had the backing of companies like Intel and BAE
Systems, we set out to build one of the most ambitious
projects in our class with no backing and no funding — so
we had to figure out ways to make it cheap. We also did
not have access to high-tech tools like CNC mills, composite
fibers, or exotic alloys. Heck, we were lucky to have a saw
and a drill, but we reasoned that plenty of amazing stuff
was built with less. The pyramids were built with hammers
and chisels, right? I’m not even sure they had wheels yet.
Using the 3D modeling program Rhinoceros, the
project began to take shape. It would have eight legs: four
on either side of a driver in the middle. It would be about
40 inches tall at the shoulder, about five feet wide, and
about three feet deep. A quick calculation showed that
the weight would be well over 300 pounds. All leg
motion would be smooth and organic, and free of any
computerized feedback or sensors. We wanted to imagine
how someone would have done what we were trying to do
in the 1800s. We even kicked around the idea of steam or
hydraulic power, but simplicity and cost-effectiveness came
into the picture and eventually electric motors seemed like
the smartest choice.
The project spanned two semesters with the first
devoted to design and engineering, and the second for
fabrication, assembly, and testing. In our first presentation,
we were naturally greeted with skepticism and cynicism.
How could five guys build a 350 pound mechanical spider
with no faculty support, no funding, and only two motors?
To be honest, we didn’t have all the answers to those
questions yet, but we had faith in our idea and the
confidence that if we could get this together, it would be
Awesomeness is always
important. Never forget that.
Slowly, the napkin sketches and computer mockups
became more refined. We researched mechanisms from all
over the world, spanning back hundreds of years. Old
Victorian-era automatons and even renaissance designs
were examined in search of a mechanism that could turn
an electric motor’s rotating shaft into a smooth and organic
walking step. The answer came in the form of a European