Dear SERVO:
I read Pete Miles’ reply in the July
SERVO about the problems of using
infrared beacons in the house and wanting
to offer another approach.
I use RobotBASIC to develop a
complete house navigation simulation
using “infrared beacons.” It works
perfectly, mainly because I used a very
different approach. (Note: If you are not
familiar with RobotBASIC, please see my
article in the June issue).
The assumption in the simulation was
that I had 10 or so beacons (each with a
unique ID code) that could be turned on by
remote control (Blue Tooth, for example).
The program used a computer
science data structure called a graph that
essentially provided a “map” of the house.
When the robot was requested from any
given room, the program checked the map
and turned on the beacons one at a time,
in the proper order, allowing the robot to
move (using the shortest path) from
where it was to where it wanted to go.
The simulation involved a complex
floor plan and demonstrated how simple
navigation can be if only some
manufacturer would provide a beacon
detector, and several beacons (that perhaps
look like smoke detectors) each with their
own ID code that could be set with DIP
switches. Since beacons could be placed
throughout the house (probably primarily
over doorways) they do not need to be
extremely powerful ... typically, they would
only need to be detectable from 15-20
feet. In the rare cases where that was not
enough, two beacons could be used to get
through a room or a hallway.
The point is, I believe infrared
beacons can provide an extremely
easy-to-use, economical way for hobbyists
to navagate a complex environment. My
simulation would even go around objects
found to be blocking the path and then
resume movement toward the beacon.
Of course, most microcontroller-based
robots would not have the memory or math
ability to deal with the graph data but the
new version of RobotBASIC ( 2.0) provides a
built-in protocol that allows all the standard
simulation commands to control a real robot
over a wireless link. This means even small
robots now have the ability to be controlled
by a complete, powerful language giving new
life to the goal of AI in small machines.
Hmmm ... looks like I rambled some,
but I am very proud of the capablities of
RobotBASIC and I think it opens many
doors to more intelligent control that
have been overlooked because of previous
limitations imposed by the required use of
simple microcontrollers.
John Blankenship
benefit from aspects of both
commercial and academic approaches.
Before beginning your next robotics
project, consider how you’d approach
design and development from a
commercial and then academic
perspective. Certainly, you want to
learn something from everything you
do, but if you’re looking at making
your innovation applicable to a larger
audience, then you have to consider
the business issues in component
selection, design, potential sales
volume, and follow-on products.
When considering component
selection, it helps to imagine that
you’re building, say, 5,000 robots.
Suddenly, a few cents for a component
or the cost of an added square
centimeter of pc board or aluminum
chassis makes a big difference in overall
cost. Sensors and other components
that are just good enough for your
application may not be pushing the
technology envelope, but customers
won’t care if the robots work as
advertised. Conversely, a new
microprocessor might be more
expensive to install initially, but
incorporating it in your design will give
you a chance to learn about the device,
and may provide a growth path for
add-ons. The bottom line is that, with a
combined approach, your robotics
innovations can be both technologically
and financially sound. SV
Dear SERVO:
This correction refers to Tom Carroll’s
article on robotic arms. The following
statements are incorrect: “the advantage
of using R/C servos is the positional
feedback;” “potentiometric feedback, as in
R/C servos allow the controlling computer
to know where each joint is positioned.”
There are no feedback mechanisms
built into any standard servo today, with
the exception of the AX- 12+ and a few
specialized servos used in Biped type-robots.
Alex Dirks, CrustCrawler
SERVO 09.2007 7