Page 157 - The Unofficial Guide to Lego Mindstorms Robots

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3. Hav e a robot competition. In Chapter 9, RoboTag, a Game for Two Robots, I'll talk about one possible robot competition.
T here are many other types of competitions. You and a friend could build robots to accomplish a specific task. Then you could
see whose robot performs better. The "Online Resources" section at the end of this c hapter lists some existing competitions.

You might think that having three or more RCXs would be even better, but it actually complicates things considerably.
Although IR communication between two RCXs is fairly straightforward, it ge ts m essy with three or more RCXs. How do you
know if an IR me ssage is destined for a specific RCX? A simple solution is to assign a specific range of message values to
v arious message pathways. For example, with three RCXs, named RCX1, RCX2, and RCX3, you might assign the message
numbers as shown in Table 7-1.

Table 7-1. Sample Message Assignments for Three-way RCX
Communication

Message Numbers Message Pathway (Two-way)

0 to 9 RCX1 to RCX2

10 to 19 RCX1 to RCX3

20 to 29 RCX2 to RCX3

A more general solution may someday be supplied by the LEGO Network Protocol, a work in progress in the online
MINDSTORMS community (see the "Online Resources" for more information).

The Allure of Telerobotics

Replacing the function of your robot's brain with that of a human brain is appealing in many situations. It's easy to program a
robot to do the same task over and over again. However, if the task changes or if the environm ent changes, the robot may have
a hard time adjusting. Humans are much better at adapting to new conditions.

On the other hand, telerobotics is a kind of ch eating. Part of the point of autonomous mobile robots is that you can set them
running and forget about them until they're done with whatever they're doing. If you build a robotic vacuum cleaner, you want
to set it running and forget about it until it's done cleaning your floors. If you used a teleoperated robotic vacuum cleaner, you'd
spend just as much time cleaning as with a conventional vacuum cleaner.

In the simplest form of telerobotics, the human can see the robot and can control it much as you might play with a radio control
car. This is basically how the remote control for Minerva works: you can see Minerva and control it by sending IR messages
from the remote control.