5 IR sensors not working code

Using Arduino Programming Questions
1

So im building a line follower robot 2 with 5 IR sensor. in my PID code error algorithm, it seems like there is a problem in giving the exact error even it shows detection in all sensors.

here is the code

float Kp=1,Ki=.5,Kd=1;
float error=0, P=0, I=0, D=0, PID_value=0;
float previous_error=0, previous_I=0;
int sensor[5]={0, 0, 0, 0, 0};
int initial_motor_speed=100;

void read_sensor_values(void);
void calculate_pid(void);
void motor_control(void);
void readings(void);

void setup()
{
pinMode(5,OUTPUT); //E1
pinMode(6,OUTPUT); //E2
pinMode(4,OUTPUT); //Left Motor Pin 1
pinMode(7,OUTPUT); //right Motor Pin 2

Serial.begin(9600); //Enable Serial Communications
}

void loop()
{
read_sensor_values();
readings();

}

void read_sensor_values()
{
sensor[0]=digitalRead(A0);
sensor[1]=digitalRead(A1);
sensor[2]=digitalRead(A2);
sensor[3]=digitalRead(A3);
sensor[4]=digitalRead(A4);

if((sensor[0]==0)&&(sensor[1]==0)&&(sensor[2]==0)&&(sensor[4]==0)&&(sensor[4]==0))
error=8; // 0 0 0 0 0

else if((sensor[0]==1)&&(sensor[1]==1)&&(sensor[2]==1)&&(sensor[4]==1)&&(sensor[4]==1))
error=9; // 1 1 1 1 1

else if((sensor[0]==0)&&(sensor[1]==0)&&(sensor[2]==0)&&(sensor[4]==0)&&(sensor[4]==1))
error=-4; // 0 0 0 0 1
else if((sensor[0]==0)&&(sensor[1]==0)&&(sensor[2]==0)&&(sensor[4]==1)&&(sensor[4]==1))
error=-3; // 0 0 0 1 1
else if((sensor[0]==0)&&(sensor[1]==0)&&(sensor[2]==0)&&(sensor[4]==1)&&(sensor[4]==0))
error=-2; //0 0 0 1 0
else if((sensor[0]==0)&&(sensor[1]==0)&&(sensor[2]==1)&&(sensor[4]==1)&&(sensor[4]==0))
error=-1; //0 0 1 1 0

else if((sensor[0]==0)&&(sensor[1]==0)&&(sensor[2]==1)&&(sensor[4]==0)&&(sensor[4]==0))
error=0; //0 0 1 0 0

else if((sensor[0]==0)&&(sensor[1]==1)&&(sensor[2]==1)&&(sensor[4]==0)&&(sensor[4]==0))
error=5;
else if((sensor[0]==0)&&(sensor[1]==1)&&(sensor[2]==0)&&(sensor[4]==0)&&(sensor[4]==0))
error=6;
else if((sensor[0]==1)&&(sensor[1]==1)&&(sensor[2]==0)&&(sensor[4]==0)&&(sensor[4]==0))
error=7;
else if((sensor[0]==1)&&(sensor[1]==0)&&(sensor[2]==0)&&(sensor[4]==0)&&(sensor[4]==0))
error=11;

}

void readings()
{
Serial.print(digitalRead(A0)),Serial.print(digitalRead(A1)),Serial.print(digitalRead(A2)),Serial.print(digitalRead(A3)),Serial.println(digitalRead(A4));
Serial.println(error);
Serial.println("-----");
delay(300);

}

2

Mysu:
So im building a line follower robot 2 with 5 IR sensor. in my PID code error algorithm, it seems like there is a problem in giving the exact error even it shows detection in all sensors.

I can think of a couple of things looking at your code but before I jump to conclusions, could you give a bit more detail regarding "it seems like there is a problem in giving the exact error".

wat you tested, wat was the expected output and what you actually got/

3

One mistake is checking sensor[4] twice and never checking sensor[3].

Rather then making a special case of all 32 patterns (you only cover 11 of them) I would assign each sensor a weight and add them together.:

void read_sensor_values()
{
  sensor[0] = digitalRead(A0);
  sensor[1] = digitalRead(A1);
  sensor[2] = digitalRead(A2);
  sensor[3] = digitalRead(A3);
  sensor[4] = digitalRead(A4);

  error = 0;

  if (sensor[0])
    error -= 4;

  if (sensor[1])
    error -= 2;

  if (sensor[3])
    error += 2;

  if (sensor[4])
    error += 4;

  // If the middle sensor is not sensing, double the error
  if (!sensor[2])
    error *= 2;

  // 00100 = 0  (Thin line centered)
  // 01110 = 0  (Thick line centered)
  // 01100 = -2
  // 00110 = +2
  // 11100 = -6
  // 00111 = +6
  // 11000 = -12
  // 00011 = +12
}