Page 112 - The Definitive Guide to Building Java Robots

Preston_5564C03.fm Page 93 Wednesday, October 5, 2005 7:21 AM

CHAPTER 3 ■ MOTION 93

elbowPos = pos;
move(ELBOW_PIN, pos);
}

public void rest() throws Exception {
shoulder(SHOULDER_REST);
elbow(ELBOW_REST);
}

public static void main(String[] args) {
try {
// get single serial port instance
JSerialPort sPort = (JSerialPort) SingleSerialPort.getInstance(1);
// create new BasicArm
BasicArm arm = new BasicArm(sPort);
// move to rest position
arm.rest();
// move elbow to 150
arm.elbow(150);
// move shoulder to 200
arm.shoulder(200);
// close serial port
sPort.close();
} catch (Exception e) {
// print stack trace and exit
e.printStackTrace();
System.exit(1);
}
}
}

The next class will formalize positions a little more than just byte 150 for the elbow and
byte 200 for the shoulder.

Code Objectives
The objective here is to make the positions easier to invoke, and to also simplify arm usage.

Code Discussion

The only field I will use in this class will be arm, of type BasicArm.
The constructor takes the JSerialPort and moves the arm to its rest position.
Of the two position methods, toA() and toB() encapsulate the positions of A and B in a
method so that you don’t have to remember them from within an invoking class. I pause between
the methods so that motion can stop since the movement is still jerky. (See Example 3-16.)