FIGURE 5.
software in last month’s article can be
reused since the arrangement of the
gripper sensors (when the fingers of
the gripper are open) is the same as
the trap. This makes the programming
much easier because we only have to
add the details of the arm’s
movements.
Once it has been determined that
an object is properly positioned in the
gripper, the fingers can be closed until
the snap action switch indicates that
contact has been made. The amount
of closure required of the servomotor
serves as an indication to the size of
the object being obtained.
Since objects can be distinguished
by their size, the robot could be
programmed, for example, to place
large objects in one basket and small
objects in another.
Since the shoulder joint is also a
servomotor, the electronics for the
arm can be any servomotor controller.
Like last month, we are using the
RobotBASIC RROS to control the
robot, so we will also use it to control
the arm. The RROS chip actually has
an alternate identity. When a second
RROS chip is connected to the main
RROS, it can be instructed to become
a servomotor controller. There are
several advantages of using two RROS
chips in this manner over using a
conventional servo controller.
Use Any
Microcontroller
Remember, you do not have to
use the RROS system (or even
RobotBASIC, for that matter) to
experiment with the concepts
discussed. The RobotBASIC code is
easy to read and well commented, so
porting it to other platforms and
processors should not be difficult. If
you are considering using the RROS
though, know that complete details
of its operation are available in the
downloadable RROS manual.
