Ultrasonic Rangefinder Forward till Near - ROBOTC.net

Sensing
Ultrasonic Rangefinder Forward till Near (cont.)
Ultrasonic Rangefinder values above the threshold of 3 inches made the program continue
looping and moving forward. Values below the threshold caused the robot to stop. The threshold
sets the point at which the robot’s behavior will change, because it marks the point at which the
(condition) in the while loop (or if-statement) will change from true to false, or false to true, and
thus change which lines of code will run.
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SensorValue[rightEncoder] = 0;
while(SensorValue[sonarSensor] > 3)
{
moveStraight();
}
}
The robot is now set and ready to run for any object the Ultrasonic Rangefinder might see…
but what happens when it doesn’t see anything at all? The sound waves have a limited range
before the echo is too soft for the sensor to pick up. In addition, some materials or surfaces can
actually deflect the sound waves away from the sensor, preventing it from hearing the echo.
What happens then?
11. Making sure that your robot is turned on and plugged in, open the ROBOTC
Debugger and Devices windows. Run the program.
© Carnegie Mellon Robotics Academy / For use with VEX ® Robotics Systems
11a. Robot > Debugger
Go to Robot > Debugger to open
the Program Debug window.
11b. Robot > Debug Windows > Devices
Open the Devices window so that you can
monitor the Ultrasonic Rangefinder values.
ROBOTC
Ultrasonic Rangefinder • 12