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Preston_5564C03.fm Page 92 Wednesday, October 5, 2005 7:21 AM

92 CHAPTER 3 ■ MOTION

Example 3-15. BasicArm.java
package com.scottpreston.javarobot.chapter3;

import com.scottpreston.javarobot.chapter2.JSerialPort;
import com.scottpreston.javarobot.chapter2.SingleSerialPort;

public class BasicArm {

private MiniSsc ssc;
// set shoulder and elbow parameters
public static final int SHOULDER_PIN = 0;
public static final int SHOULDER_MAX = SSCProtocol.MAX;
public static final int SHOULDER_MIN = SSCProtocol.MIN;
public static final int SHOULDER_REST = 55;
public static final int ELBOW_PIN = 1;
public static final int ELBOW_MAX = SSCProtocol.MAX;
public static final int ELBOW_MIN = SSCProtocol.MIN;
public static final int ELBOW_REST = 65;
// instance variables of current position
private int shoulderPos = SSCProtocol.NEUTRAL;
private int elbowPos = SSCProtocol.NEUTRAL;

//constructor taking JSerialPort as parameter
public BasicArm(JSerialPort sPort) throws Exception {
ssc = new MiniSsc(sPort);
}

// passthrough to ssc
private void move(int pin, int pos) throws Exception {
ssc.move(pin, pos);
}

// move the shoulder
public void shoulder(int pos) throws Exception {
if (pos < SHOULDER_MIN || pos > SHOULDER_MAX) {
throw new Exception("Out of shoulder range.");
}
shoulderPos = pos;
move(SHOULDER_PIN, pos);
}

// move the elbow
public void elbow(int pos) throws Exception {
if (pos < ELBOW_MIN || pos > ELBOW_MAX) {
throw new Exception("Out of elbow range.");
}