File content as of revision 16:60e70bef7828:

#include "mbed.h"
#include "Camera.h"
#define STRAIGHT 0.00094f
#define FULLRIGHT 0.0013f
#define FULLLEFT 0.0005
#define MIN_TURN_RATIO 0
#define MAX_TURN_RATIO 1
#define MIN_SPEED 0.15
#define MAX_SPEED 0.4
#define TURN_TIME 40
#define STRAIGHT_TIME 15
#define DEFAULT_THRESHOLD 65
#define BLIND_LENGTH 20

PwmOut servo(PTE20);
PwmOut motor_left(PTA5);
PwmOut motor_right(PTC8);
DigitalOut DIR_L(PTD4);
DigitalOut DIR_R(PTA4);
Serial pc(USBTX, USBRX);
Camera cam(PTE23, PTE21, PTB3);
int turnCounter = 0;
int threshold = DEFAULT_THRESHOLD;
float wheelPos = STRAIGHT;
bool idle = false;
int leftBlind = 0;
int rightBlind = 0;

/*
    Function: setAccel
    Description: Sets the speed for the right and left motors individually based
                 on the turning angle. 
*/
void setAccel(float turnAngle){//, float speed){
    turnAngle -= STRAIGHT; //this gets a value from -0.00035 and +0.00035
    float turnRatio = abs(turnAngle)/0.00035f;
    float newSpeed = ((MAX_SPEED - MIN_SPEED)*(1-turnRatio)/3)+MIN_SPEED;
    motor_left.write(newSpeed + 0.5 * newSpeed * (turnAngle / .00035f));
    motor_right.write(newSpeed - 0.5 * newSpeed * (turnAngle / .00035f));
}//end setAccel

/*
    Function: turnWheels
    Description: Turns the wheels in order to stay between two black lines seen
                 by the camera
*/
void turnWheels(int frame[]){
    int positionSum = 0;
    int numDarks = 0;
    for(int i = 0; i < 128; i++){
        if(frame[i] < threshold){
            positionSum += i;
            numDarks++;
        }
    }
    float averagePos = 0;

        if (numDarks == 0) {
             if(turnCounter >= (STRAIGHT_TIME)){
                 wheelPos = STRAIGHT;
                 turnCounter = TURN_TIME;
                 leftBlind = 0;
                 rightBlind = 0;
            }
        }
        
        else {
            averagePos = positionSum / numDarks;
            
            if(((averagePos <= 64 - leftBlind)) && ((wheelPos >= STRAIGHT) || turnCounter >= TURN_TIME)){
                float powerRatio = (averagePos / (64 - leftBlind)) * MAX_TURN_RATIO + MIN_TURN_RATIO;
                powerRatio = sqrt(powerRatio);
                wheelPos = STRAIGHT + (FULLRIGHT - STRAIGHT) * powerRatio;
                turnCounter = 0;
                leftBlind = 0;
                rightBlind = BLIND_LENGTH;
            }
            
            else if((averagePos >= 64 + rightBlind) && (wheelPos <= STRAIGHT || turnCounter >= TURN_TIME)){
                float powerRatio = (1 - (averagePos - 64 - rightBlind) / (64 - rightBlind)) * MAX_TURN_RATIO + MIN_TURN_RATIO;
                powerRatio = sqrt(powerRatio);
                wheelPos = STRAIGHT - (STRAIGHT - FULLLEFT) * powerRatio;
                turnCounter = 0;
                leftBlind = BLIND_LENGTH;
                rightBlind = 0;
            }
        }
        turnCounter++;
    servo.pulsewidth(wheelPos);
}

void display(int frame[]){
    char draw = 'x';
    for(int i = 0; i< 128; i++){
        if (frame[i] <65) draw = '|';
        else draw = '-';
        pc.printf("%c", draw);
        draw = 'x';
    }
    pc.printf("\r");
}

void setThreshold(){
    cam.capture();
    int low = 99;
    int high = 0;
    for(int i = 0; i < 128; i++){
        if(cam.imageData[i] > high) high = cam.imageData[i];
        if(cam.imageData[i] < low) low = cam.imageData[i];
    }
    threshold = (high + 2 * low) / 3;
}

int main() {    
    setThreshold();
    motor_left.period_us(50);
    motor_right.period_us(50);
    DIR_R = 1;
    DIR_L = 0;
    servo.period(0.020f);
    while(1){
        wait_ms(10);
        cam.capture();
        //display(cam.imageData);
        turnWheels(cam.imageData);      
        if(!idle) setAccel(wheelPos);
    }
}