by David Geer
Contact the author at geercom@alltel.net
Open Robot Platform
is Student’s Delight!
Roboticist and PhD candidate Abe Howell created the Open Robot platform
so it could provide broad applications across robotics education
from kindergarten through the university level.
Open Robot is, not surprisingly,
completely open source.
Teachers and students may
modify and distribute all the robot’s
documentation, software, printed
circuit board designs, and mechanical
design files as long as credit to the
inventor is maintained.
Howell is eager to see an open
source community grow up around
the Open Robot, adding hardware,
software, sensors, and “mechanical
end-effectors.”
Its Construction
The Open Robot uses multiple
on-board sensors in an array which
gather input from surrounding
environments. Its Sharp GP2D120
infrared sensors enable the robot to
sense the presence, distance, and
relative location of obstacles. “The
distance to an object is calculated in
inches, centimeters, or other standard
units of length,” Howel explains.
These sensors teach students to
calibrate the robots. By taking eight-bit obstacle detection readings at
incremental distances between the
sensor and object, students may plot
the sensor’s response. From this, they
create regression lines and functions
to arrive at detection distances from
Back of Open Robot with battery pack.
objects when future readings are
taken, Howell continues.
The robot senses light, as well as
objects and surfaces. The robot’s two
forward CdS light sensors enable it
to follow or avoid ambient light,
depending on intensity.
The Open Robot also comes with
capability for Radio Frequency
Identification (RFID) tag reader
applications and experiments. A chip
module and antenna are integrated
into the robot to read and write data
to and from passive RFID tags (which
the user must purchase separately).
The tags may be positioned on
the floor in the Open Robot’s environment, and its antenna will read
them when the robot passes
over. The robot also uses
in-range RFID tag discovery to
determine when tags are in
range and when to stop.
These RFID tags are great
for doing maze navigation
experiments. “Simply program
each tag with a special code,
then place them throughout
the maze,” says Howell. By
creating artificial intelligence
for the robot, students enable
it to navigate the maze using
the robot’s built-in RFID reader.
Since RFID tags have no power
source, they receive power
when an antenna comes within
Open Robot controller board center features
a PIC18F4520 microcontroller.
10 SERVO 01.2009
