Build Your Own Combat Robot

256 Build Your Own Combat Robot
FIGURE 11-9
Simple infrared
receiver circuit.
(courtesy of
Bob Gross)
GP1U52X
3
2
1
5V
Output
8
C1
U1
C2 C3 C4 C5
7
6
R1 until the voltage drops to zero, and then remember the turn position. Continue
turning the potentiometer in the same direction until the voltage jumps back up to
5 volts. At this point, you have found the sensitivity band with of this detector.
Now back off the potentiometer position to someplace between the two positions
you have observed. The voltage should be back to zero. Here you should be at the
center frequency at which the test infrared beacon is transmitting.
The last feature that must be included in an autonomous robot is an actual R/C
receiver. For safety purposes, you will want to be able to remotely shut down the
robot. Even remotely turning on the robot is a good idea. The R/C receiver can be
hooked up to a switch that turns power on and off to the main microcontroller in
this robot.
R1
1 2 3 4
5
R2
U1 567 tone decoder
R1 50KΩ -10 turn pot
R2 5.6KΩ
C1 .1µF
C2 .01µF
C3, C4 4.7µ F
C5 .047µF
5V
Bob Gross and Thumper
Bob Gross implemented manyof the features discussed in this chapter while building his
champion robot Thumper (which won the autonomous class competition at Robot Wars
1997). To give you an idea of how effective a good autonomous robot can be, Thumper
took on Jim Smentowski’s R/C robot, Hercules, who weighed in 70 pounds heavier than
Thumper. Through most of the match, Thumper was in the lead, chasing Hercules around
the ring repeatedlyand even pinning him against the wall twice. In the end, however,
Thumper’s drive motors burned out because of the extended pins. At that point, the
heavier—and bythen, stronger—Hercules was able to knock Thumper over and pin him
against the wall as time ran out. Although Thumper didn’t win that match, the crowd went
wild seeing a fullyautonomous bot give a remote-controlled machine a run for its money.