Autonomous Photosensor Programming

[MisterL]

This is all helpful, I only wish I had more expertise in Java. This is still kind of a new thing for me to learn so I am completely out of my league. Thank you for your help! If you are able to help a little more on the
if(middle.get())
concept that would help. I can't help but feel I am missing something here.

[ArchVince]

Originally Posted by MisterL

This is all helpful, I only wish I had more expertise in Java. This is still kind of a new thing for me to learn so I am completely out of my league. Thank you for your help! If you are able to help a little more on the
if(middle.get())
concept that would help. I can't help but feel I am missing something here.

The line sensors send true if a line is underneath and false if there is not a line underneath. The get method return that value. Basically, middle is the digital input plugged in to slot 1. if(middle.get()) checks to see if there is a line underneath that sensor. That's my impression of it, anyway. We only used line sensors temporarily, since we aren't sure if we'll even have a functioning arm to use with them.

[MisterL]

Well heres a new development, we only own one photosensor, so should I only have the middle part of the code? Or should I use a whole new code?

[Bot190]

You should have gotten three of the photoelectic sensors in the Kit of Parts.
As others have said, you want to put the three line sensors in a row, spaced apart a little. Then you have to adjust them such that the LED's on the sensors change colors as you move the robot past the tape.

Then, depending on how you wired them, you will get a value from the sensor with a digitalinput. The Get method returns a value, 1 or 0 when the sensor sees the line, or doesn't, depending on how you wired them.

From there, you basically go forward while the center one is on the line, then if either side sees the tape, turn a bit until only the center sees the line.

[Hadyn Fitzgeral]

Here's my teams code that I wrote for this. We can do the Y + the straight profiles of the line. Since this is fairly outdated I am not to worried about leeching.

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package org.freelance.logic;

import edu.wpi.first.wpilibj.Timer;
import org.freelance.sensors.Photoswitch;
import org.freelance.sys.MecanumDrive;
import org.freelance.util.Constants;

/**
 *
 * @author Freelance Robotics (Hadyn Fitzgerald)
 */
public class Linetracking {

    private boolean done = false;
    private boolean left = false;
    private int profile = 1; //1 == Y, 0 == Straight

    private Photoswitch leftSwitch;
    private Photoswitch centerSwitch;
    private Photoswitch rightSwitch;

    private final byte NONE_OPCODE = 0, LEFT_OPCODE = 1, CENTER_OPCODE = 2,
                       RIGHT_OPCODE = 4, ALL_OPCODE = 7;

    private double FORWARD = -.5, BACKWARD = .5, LEFT =  -.425, RIGHT = .425;

    private int stage = 0;

    public Linetracking() {
        initLineTracking();
    }

    private void initLineTracking() {
        /**
         * Construct Photoswitches
         */
        leftSwitch = new Photoswitch(Constants.LEFT_SLOT);
        centerSwitch = new Photoswitch(Constants.CENTER_SLOT);
        rightSwitch = new Photoswitch(Constants.RIGHT_SLOT);
    }

    public byte getType() {
        byte type = 0;

        if(leftSwitch.get())
            type += 1;

        if(centerSwitch.get())
            type += 2;

        if(rightSwitch.get())
            type += 4;

        System.out.println(type);

        return type;
    }

    public boolean process(MecanumDrive drive) {
        byte type = getType();
        switch(type) {

            case NONE_OPCODE:
                if(profile == 0) {
                    drive.controllerDrive(0, 0, 0);
                } else
                    if(stage == 0) {
                        for(int a = 0; a < 50; a++) {
                            if(left)
                                drive.controllerDrive(0, 0, -.3);
                            else
                                drive.controllerDrive(0, 0, .3);
                        }
                        while(getType() != CENTER_OPCODE) {
                            if(getType() == ALL_OPCODE)
                                break;
                            if(left)
                                drive.controllerDrive(0, LEFT, 0);
                            else
                                drive.controllerDrive(0, LEFT, 0);
                        }
                        stage++;
                    } else if(stage == 1) {
                        for(int a = 0; a < 35; a++) {
                            if(left)
                                drive.controllerDrive(0, 0, .3);
                            else
                                drive.controllerDrive(0, 0, -.3);
                        }
                        done = true;
                    } else {
                        drive.controllerDrive(0, 0, 0);
                    }
                break;

            case LEFT_OPCODE:
                while(getType() != CENTER_OPCODE) {
                    if(getType() == NONE_OPCODE || getType() == ALL_OPCODE)
                        break;
                    drive.controllerDrive(0, RIGHT, 0);
                }
                break;

            case CENTER_OPCODE:
                drive.controllerDrive(FORWARD, 0, 0);
                break;

            case RIGHT_OPCODE:
                while(getType() != CENTER_OPCODE) {
                    if(getType() == NONE_OPCODE || getType() == ALL_OPCODE)
                        break;
                    drive.controllerDrive(0, LEFT, 0);
                }
                break;

            case ALL_OPCODE:
                drive.controllerDrive(0, 0, 0);
                if(profile == 0) {
                    done = true;
                }
                break;
        }
        return done;
    }

    public void reset() {
        stage = 0;
    }
}

[Robby Unruh]

How are you guys programming your Y's? I'm having some trouble with mine. Any tips would be really appreciated.

[Patrickwhite]

Originally Posted by Robby Unruh

How are you guys programming your Y's? I'm having some trouble with mine. Any tips would be really appreciated.

Our robot drives straight on the line, so it notices when the middle sensor is no longer over the tape, but the left and right both are. At that point, we begin turning in the direction we want to go. Using the code you've already posted as a template:

if(left.get() && !middle.get() && right.get()) {
        // turn left or right, depending on what you want
    }

It wouldn't go on as another else, it would be a separate if, or it would never be triggered.