Build Your Own Combat Robot

178 Build Your Own Combat Robot
of 60 pounds and larger, but is generally too big for smaller robots. The Isaac system
also requires that robot builders have more skills in electronics and software programming
than those who use off-the-shelf R/C systems.
The reliability, amazing flexibility, and competition-friendliness of this radio
system has made the Isaac system a hit among many top BattleBots teams. Because
the Isaac system has proven to be reliable and resistant to radio interference from
other radios, BattleBots is heavily encouraging the use of this controller in its events.
note The BattleBots organization has reserved the 902- to 905-MHz and the 925- to
928-MHz frequencies for the IFI Robotics Isaac robot controllers. For most people, this doesn’t
mean much; but to those robot teams that want to build their own R/C systems using
900-MHz radios, this means that they will be prohibited from using these frequencies at a
BattleBots tournament.
Radio Modems
The actual RF transmission for the Isaac robot controllers uses a pair of RS-422
radio modems made by Ewave, Inc. (www.electrowave.com). RS-422 is a serial
communication protocol that is more reliable than the standard RS-232 serial
communication with which most of us are familiar. These radio modems have
built-in error-checking software to help ensure that the data being transmitted is
reliable and correct. These modems are bi-directional so that data can be transmitted
both ways with the same set of hardware.
Some robot builders prefer to build their own R/C equipment. There is nothing
wrong with that, and some people can build systems much better than what can be
purchased off the shelf. The subject of developing reliable R/C equipment is beyond
the scope of this book. Suffice it to say that you do not need to be an electrical
engineer to build yourself a simple remote control system. Products are available
to help you assemble one of these systems.
To build your own R/C system, you will need three major subsystems:
■ The operator interface Used to convert operator control commands—
such as velocity, direction, and weapons—into electronic information
to be transmitted.
■ The RF communication system Used to transmit data from the operator
interface to the robot.
■ The robot controller Converts the radio data into command signals that
can be used to control the robot.
One of the easiest ways to establish RF communication with your robot is to
use a radio modem. A radio modem sends serial data from a host device to a remote
device—from an operator interface to the robot. All computers and virtually