dc_motor_control.ino

int potin = 1;
int mot1 = 7;
int mot2 = 6;
int sensorValue = 0;
//int pid = 0;
//int pwmcontrol=4;
int init_angle= 0;
int final_angle= 0;
int final_sensor_value= 0;
int first_time= 1;
float error= 0;
float last_error =0;
float integral= 0;
float differential= 0;
int time_period =5;//in ms
float p = 2.5;
float i =5;
float d = .017;


// the setup routine runs once when you press reset:

void setup()

{
  
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
  //setting of pin:
  pinMode(potin,INPUT);
  pinMode(mot1,OUTPUT);
  pinMode(mot2,OUTPUT);
  //pinMode(pwmcontrol,OUTPUT);
}
void turn(int a, int b)
{
    analogWrite(mot1,a);
    analogWrite(mot2,b);
    Serial.println("\n mot1: ");
    Serial.println(a);
    Serial.println("\n mot2: ");
    Serial.println(b);
} 

// the loop routine runs over and over again forever:
void loop() 
{ // read the input on analog pin 0:
  int sensorValue = analogRead(potin);

  if(first_time==1){
  Serial.println("\n Initial Angle: ");  
  init_angle = (sensorValue*360.0)/1024.0;
  Serial.println(init_angle);
  //Calculating the final angle 
  Serial.println("\n Final Angle: ");
  final_angle = (init_angle + 180)%360;
  Serial.println(final_angle);
  final_sensor_value = (final_angle*1024.0)/360.0;
  //final_sensor_value = (sensorValue + 512)%1024;
  first_time=0;
  }

  
  // Convert the analog reading (which goes from 0 - 1023) to a voltage (0 - 5V):
  float voltage = sensorValue * (4.84 / 1023.0);
  // print out the value you read:
  Serial.println("\n voltage: ");
  Serial.println(voltage);
  Serial.println("\n sensorValue: ");
  Serial.println(sensorValue);
  
 
  //error=(final_sensor_value - sensorValue) * (5.0 / 1023.0);
  error=(final_sensor_value - sensorValue);
  integral+= (error*time_period)/1000;
  differential= ((error-last_error)/time_period)*1000;
  //pwm calculation:
  int pwm = p*error + i*integral + d*differential;
  last_error = error;
  if(pwm > 255){pwm = 255;}
  if(pwm < -255){pwm = -255;}
  if(pwm > 0){turn(pwm,0);}
  if(pwm < 0){turn(0,-pwm);}  
 
  delay(time_period);
    
  }