Colony

/**

 * @file lineFollow.c

 * @defgroup lineFollwing Line Following

 *

 * Takes care of following a line. Running this program is done by calling the

 * init() function and then the lineFollow(speed) command.  However, direct use

 * of this class is discouraged as its behavior is used by lineDrive.c, which

 * extends this class to provide behavior functionality.

 *

 * @author Dan Jacobs and the Colony Project

 * @date 11-1-2010

 */

#include "lineFollow.h"

//! The number of bits expected in a barcode

#define CODESIZE 5

#define LINE_COLOR 200

int countHi = 0;

int countLo = 0;

int maxAvg, avg;

int barCode[ CODESIZE ];

int barCodePosition=0;

int duration = 0;

int lastColor = 0;

char isReset = 0;

int turnDistance=0;

//! Counts the number of full line readings before we determine an intersection

int intersectionFilter=0;

int disableBarCode=0;

//! Keeps track of where the encoder of one motor started, for use in turns.

int encoderStart = -1;

int encoderReset = 0;   // 0 if encoderStart has no value set

void lineFollow_init()

{

        analog_init(0);

        lost = 0;

        intersectionFilter=0;

        disableBarCode=0;

}

/**

 * Follows a line at the given speed.

 * @param speed The speed with which to follow the line.

 */

int lineFollow(int speed)

{

        int colors[5];

        int position;

        updateLine(colors);

        position = lineLocate(colors);

        //not on line

        if(position == NOLINE)

        {

                if(lost++ > 20)

                {

                        orb2_set_color(GREEN);

                        motors_off();

                        return LINELOST;

                }

        }

        else if(position == FULL_LINE)

        {

                if(intersectionFilter++ > 4)

                {

                        orb2_set_color(RED);

                        barCodePosition=0;

                        disableBarCode=50;

                }

        }

        //on line

        else

        {

                position*=30;

                orb2_set_color(ORB_OFF);

                motorLeft(min(speed+position, 255));

                motorRight(min(speed-position, 255));

                lost=0;

                intersectionFilter=0;

        }

    // If we're running over a line, stop reading barcodes for a sec

        if(disableBarCode-- > 0)

        {

        // Return intersection once we cross the line

                if(disableBarCode) return NOBARCODE;

                return INTERSECTION;

        }

        updateBarCode();

        return getBarCode();

}

/**

 * Implements the left merge, assuming a line exists to the left.  Works by

 * turning off the line at an increasing angle and waiting to hit another line

 * on the left.

 */

int mergeLeft()

{

        motor_l_set(FORWARD, 200);

        if(turnDistance!=21)motor_r_set(FORWARD, 230);

        else motor_r_set(FORWARD, 210);

        int colors[5];

        updateLine(colors);

        int position = lineLocate(colors);

        if(position>3 || position<-3)turnDistance++;

        if(turnDistance>20)

        {

        turnDistance=21;

                if(position<3 && position>-3)

                {

                        turnDistance = 0;

                        return 0;

                }

        }

        return 1;

}

/**

 * Implements the right merge, assuming a line exists to the right.  Works by

 * turning off the line at an increasing angle and waiting to hit another line

 * on the right.

 */

int mergeRight()

{

        motor_r_set(FORWARD, 200);

        if(turnDistance!=21)motor_l_set(FORWARD, 230);

        else motor_l_set(FORWARD, 210);

        int colors[5];

        updateLine(colors);

        int position = lineLocate(colors);

        if(position>3 || position<-3)turnDistance++;

        if(turnDistance>20)

        {

        turnDistance=21;

                if(position<3 && position>-3)

                {

                        turnDistance = 0;

                        return 0;

                }

        }

        return 1;

}

/**

 * Turns left at a cross of two lines.  Assumes that we are at lines in a cross

 * pattern, and turns until it sets straight on the new line.

 * @return 0 if turn finishes otherwise return 1

 */

int turnLeft()

{

        /*motor_l_set(BACKWARD, 200);

        motor_r_set(FORWARD, 200);

        int colors[5];

        updateLine(colors);

        int position = lineLocate(colors);

        if(position>2 || position<-2)turnDistance++;

        if(turnDistance>1)

        {

                if(position<3 && position>-3)

                {

                        turnDistance = 0;

                         return 0;

                }

        }

        return 1;*/

        motor_l_set(BACKWARD,200);

        motor_r_set(FORWARD,200);

        if(!encoderReset)

        {

            encoderStart = encoder_get_x(RIGHT);

            encoderReset = 1;

        }

        if(encoder_get_x(RIGHT) < encoderStart)

        {

            encoderStart = 0;

            // Temporary: display an "error message" in case of overflow.

            // Using this for debugging, take it out soon!

            motor_l_set(FORWARD,0);

            motor_r_set(FORWARD,0);

            orb_set_color(WHITE);

            delay_ms(2000);

        }

        if(encoder_get_x(RIGHT) - encoderStart > 300)

        {

            encoderReset = 0;

            return 0;

        }

        return 1;

}

/**

 * Turns right at a cross of two lines.  Assumes that we are at lines in a cross

 * pattern, and turns until it sets straight on the new line.

 * @return 0 if the turn finishes otherwise return 1

 */

int turnRight()

{

        motor_r_set(BACKWARD, 200);

        motor_l_set(FORWARD, 200);

        int colors[5];

        updateLine(colors);

        int position = lineLocate(colors);

        if(position>2 || position<-2)turnDistance++;

        if(turnDistance>1)

        {

                if(position<3 && position>-3)

                {

                        turnDistance = 0;

                         return 0;

                }

        }

        return 1;

}

int getBarCode()

{

        if(barCodePosition != CODESIZE)

        return NOBARCODE ;

    else

    {

        int temp = 0;

        for(int i=0; i<CODESIZE; i++)

            temp += (barCode[i] << i);

        barCodePosition = 0;

        return temp;

    }

}

void updateLine(int* values)

{

        for(int i = 0; i<5; i++)

                values[i] = (read_line(4-i) < LINE_COLOR ? LWHITE : LBLACK);

}

int lineLocate(int* colors)

{

        int i;

        int wsum = 0;

        int count=0;

        for(i = 0; i<5; i++)

        {

                count += colors[i]/2;

                wsum += (i)*colors[i];

        }

        if(count==0)

                return NOLINE;

        if(count==5)

                return FULL_LINE;

        return (wsum/count)-4; // Subtract 4 to center the index around the center.

}

// new version by Alex

void updateBarCode()

{

    // USING THESE GLOBAL VARIABLES

    // global int duration = 0;

    // global int lastColor = 0;

    // global int barCodePosition = 0;

    // global char isReset = 0;

    // Average the readings of the last 2 sensors

    if(read_line(6) - read_line(7) > 150 || read_line(6) - read_line(7) < -150)

    {

        return;

    }

    int curReading = (read_line(6) + read_line(7)) / 2;

    int curColor;

    if(curReading > BLACK_THRESHOLD)

        curColor = LBLACK;

    else if(curReading < GREY_THRESHOLD)

        curColor = LWHITE;

    else

        curColor = LGREY;

    // Just an error check

    if(barCodePosition > CODESIZE)

    {

        barCodePosition = 0;

    }

    // We are only interested in consecutive color values

    if(curColor == lastColor)

    {

        duration++;

    }

    else

    {

        duration = 0;

        lastColor = curColor;

    }

    if(duration > MAX_DURATION)

    {

        // Now we assume our reading is significant - a bit, or a white space

        // Only read a value if we have read 0 first (isReset == 1)

        if(isReset && (curColor == LBLACK || curColor == LGREY) )

        {

            isReset = 0;

            usb_puts("Read barcode bit: ");

            usb_puti(barCodePosition);

            usb_puts(" = ");

            usb_puti(curColor);

            usb_puts(", curReading = ");

            usb_puti(curReading);

            usb_puts(".\n");

            barCode[barCodePosition++] = (curColor == LBLACK) ? 1 : 0;

        }

        else if(curColor == LWHITE)

        {

            isReset = 1;

        }

    }

    if(duration > TIMEOUT_DURATION && barCodePosition != 0)

    {

        usb_puts("TIMED OUT. BARCODE READER RESET.\n");

        barCodePosition = 0;

        duration = 0;

    }

}

// Dan's version

/*void updateBarCode()

{

        //! Note: currently only uses one of the barcode sensors.

        //maps the sensors to the analog input ports

        int ports[2] = {8,1};

        int current[2];

//        current[0] = analog_get10(ports[0]);

        //current[1] = analog_get10(ports[1]);

    current[1] = read_line(6);

        if(current[1] > 150)

        {

                if(countHi++ == 0)

                {

                        avg = 500;

                        maxAvg = 500;

                }

                else

                {

                        avg = 3*avg + current[1];

                        avg/=4;

                        maxAvg = max(maxAvg, avg);

                }

        }

        else if(countHi > 5)

        {

                if(countLo++ > 15)

                {

                        countHi = countLo = 0;

                        if(maxAvg > 825)

                orb1_set_color(RED);

                        else orb1_set_color(BLUE);

                        barCode[barCodePosition++] = maxAvg > 825 ? 1:0;

                }

        }

        else countHi/=2;

        if(countHi==0)countLo=0;

}*/

int min(int x, int y){return x>y ? y : x;}

int max(int x, int y){return x<y ? y : x;}

void motorLeft(int speed){

        ((speed-=127)>=0)?motor_l_set(FORWARD, 160+speed*95/128):motor_l_set(BACKWARD, 160-speed*95/127);

}

void motorRight(int speed){

        ((speed-=127)>=0)?motor_r_set(FORWARD, 160+speed*95/128):motor_r_set(BACKWARD, 160-speed*95/127);

}