additional actuator was adapted to that task.
“Using the Autodesk Inventor CAD that we used to
design our competition robots, we designed hand
assemblies that matched what we learned from our
prototypes, and started to fabricate hand parts. After
much tinkering, we had two hand mechanisms that could
attach to and operate the guitar,” Spatz explained.
Once the vision and control software were completed
on the laptop, and the hand mechanisms were ready to
play the guitar, the team simply needed to create an I/O
link between them. “We were hoping to find an
inexpensive, all-in-one solution to go directly from the
USB port on the laptop to the 12V high current signals
we needed to drive our solenoids (the hand actuators).
After much searching, we found it at a small irrigation
controls company on the web called Bibaja,” Spatz
Bibaja’s I/O solution used a small, cheap controller
board designed for controlling irrigation systems. It
translated the USB data into 16 channels of 12 volt
output, Spatz commented. “We got the board, wired up
the system, and were quickly playing Guitar Hero even
better than we expected. There was still much
experimenting and improving to do, but we knew we
were in the ballpark,” Spatz conveyed.
Using multiple variables in the programming, the
team was able to make many adjustments. They were
able to adjust the screen size, the locations for the
camera and system to watch, the brightness level and
duration of the light required to
indicate a note, the ranges that
occurred between notes, the time
delay allowable between seeing a
note and playing it on the guitar,
the length of the output signal to
the solenoid actuators and the
length of other signals, and the
length of the note required to
activate the whammy bar, listed
Spatz. With hours of practice and
adjustment, they arrived at the
best settings for the robot to play
at the most expert level that it
The robot’s power supply, relay board, and control
panel on the back of the robot.
Body and Soul
Next, the roboticists
constructed Titan’s body on
which they mounted everything.
They made it out of PVC
pipe, with a glossy black
Close-up of the robot as its
actuators play the guitar.
SERVO 09.2010 13