For the enthusiast who loves to build simple robot.This code is executable in arduino IDE

#define inA 2 #define inB 3 #define inC 4 #define inD 7 #define enA 5 #define enB 6

int leftBaseSpeed = 130; int rightBaseSpeed = 130; int maxSpeed = 255;

// SENSOR PARAMETERS

#define NUM_SENSORS 5

int thresholds[NUM_SENSORS] = {450, 450, 450, 450, 450}; int ledPins[5] = {8, 9, 10, 11, 12}; int sensorValues[NUM_SENSORS], sValues[NUM_SENSORS], lastSensor, psValues[NUM_SENSORS], mode,distR = 0, distF = 0;// durationF = 0, durationR = 0; unsigned long durationF=0,durationR=0; // PID PARAMETERS

float kp = 48.0; float kd = 4.7; float ki = 0.75; int prevError = 0, error = 0; float p, i = 0, d;

void setup() { // put your setup code here, to run once:

//Initialize Motor Pins motorInit(); //Initialize Other Variables and Pins otherInit(); }

void loop() { //if(distF<value&&disR<value) wallFollow(); lineFollow(); }

void motorInit() { pinMode(inA, OUTPUT); pinMode(inB, OUTPUT); pinMode(inC, OUTPUT); pinMode(inD, OUTPUT); pinMode(enA, OUTPUT); pinMode(enB, OUTPUT);

//Setting The Motor to zero speed digitalWrite(inA, HIGH); digitalWrite(inB, HIGH); digitalWrite(inC, HIGH); digitalWrite(inD, HIGH); }

void otherInit() { //for (int i = 0; i < 5; i++) pinMode(ledPins[i], OUTPUT);

lastSensor = 0; prevError = 0; Serial.begin(9600); } int readSensor() { for (int i = 0; i < NUM_SENSORS; i++) { //Read the raw sensor values sensorValues[i] = analogRead(i); //Serial.print(i+1); Serial.print(" : "); Serial.println(sensorValues[i]); delay(700); //Covert them into digital readings //And turning the corresponding LED on or off if (sensorValues[i] > thresholds[i]) { sValues[i] = 0; //digitalWrite(ledPins[i], LOW); } else { sValues[i] = 1; //digitalWrite(ledPins[i], HIGH); } //detectPos(); /if (sensorValues[i] > thresholds[i]) { sValues[i] = psValues[i] + mode; } else { sValues[i] = psValues[i] - mode; }/ } if (sValues[0] == 0 && sValues[1] == 0 && sValues[2] == 1 && sValues[3] == 0 && sValues[4] == 0) { error = 0; } else if (sValues[0] == 0 && sValues[1] == 0 && sValues[2] == 0 && sValues[3] == 1 && sValues[4] == 0) { error = 1; } else if (sValues[0] == 0 && sValues[1] == 1 && sValues[2] == 0 && sValues[3] == 0 && sValues[4] == 0) { error = -1; } else if (sValues[0] == 0 && sValues[1] == 0 && sValues[2] == 0 && sValues[3] == 0 && sValues[4] == 1) { error = 3; lastSensor = 2; } else if (sValues[0] == 1 && sValues[1] == 0 && sValues[2] == 0 && sValues[3] == 0 && sValues[4] == 0) { error = -3; lastSensor = 1; } else if (sValues[0] == 0 && sValues[1] == 0 && sValues[2] == 1 && sValues[3] == 1 && sValues[4] == 0) { error = 2; } else if (sValues[0] == 0 && sValues[1] == 1 && sValues[2] == 1 && sValues[3] == 0 && sValues[4] == 0) { error = -2; } else if (sValues[0] == 0 && sValues[1] == 0 && sValues[2] == 1 && sValues[3] == 1 && sValues[4] == 1) { error = 4; lastSensor = 2; } else if (sValues[0] == 1 && sValues[1] == 1 && sValues[2] == 1 && sValues[3] == 0 && sValues[4] == 0) { error = -4; lastSensor = 1; } else if (sValues[0] == 0 && sValues[1] == 1 && sValues[2] == 1 && sValues[3] == 1 && sValues[4] == 1) { error = 5; lastSensor = 2; } else if (sValues[0] == 1 && sValues[1] == 1 && sValues[2] == 1 && sValues[3] == 1 && sValues[4] == 0) { error = -5; lastSensor = 1; } else if (sValues[0] == 0 && sValues[1] == 0 && sValues[2] == 0 && sValues[3] == 0 && sValues[4] == 0) { if (lastSensor == 1) { error = -6; } else if (lastSensor == 2) { error = 6; } }

return error; }

void lineFollow() { int pid;

//Read the sensor values and calculate error error = readSensor();

p = error * kp; i = (i + error) * ki; //i=i+ilast; d = (error - prevError) * kd; pid = int(p + i + d);

//lasti=i; //motor_control(); wheel(leftBaseSpeed - pid, rightBaseSpeed + pid); prevError = error; if (error - prevError == 0) delay(10); }

void wheel(int leftSpeed, int rightSpeed) { if ( leftSpeed == 0) { digitalWrite(inC, 1); digitalWrite(inD, HIGH); } if ( leftSpeed > 0) { digitalWrite(inC, 1); digitalWrite(inD, 0); //delay(5); } else if ( leftSpeed < 0) { digitalWrite(inC, 0); digitalWrite(inD, 1); //delay(5); }

if (rightSpeed == 0) { digitalWrite(inA, HIGH); digitalWrite(inB, HIGH); } if ( rightSpeed > 0) { digitalWrite(inA, 1); digitalWrite(inB, 0); //delay(10); } else if ( rightSpeed < 0) { digitalWrite(inA, 0); digitalWrite(inB, 1); //delay(10); } if (abs(leftSpeed) > maxSpeed) leftSpeed = maxSpeed; if (abs(rightSpeed) > maxSpeed) rightSpeed = maxSpeed;

analogWrite(enA, abs(rightSpeed)); analogWrite(enB, abs(leftSpeed)); }