Linetracer.ino

int IR_output1 = 2;             //connected to analog 0
int IR_output2 = 1;             //connected to analog 1
int IR_output3 = 0;             //connected to analog 2
int threshold = 100;
int delaytime = 200;

int COUNT = 0;                  // DEBUG PURPOSE TIME-ELAPSE CACHE
int COUNT_THRESHOLD = 3;

void setup() 
{
  Serial.begin(9600);
  pinMode(IR_output1, INPUT);   //IR sensor1 output 
  pinMode(IR_output2, INPUT);   //IR sensor2 output 
  pinMode(IR_output3, INPUT);   //IR sensor3 output
  pinMode(7, OUTPUT);     //모터 A 방향설정1
  pinMode(8, OUTPUT);     //모터 A 방향설정2
  pinMode(4, OUTPUT);     //모터 B 방향설정1  
  pinMode(5, OUTPUT);     //모터 B 방향설정2
}

void stop_march ()
{
  //모터 A설정
  digitalWrite(7, HIGH);    //모터 A방향설정1
  digitalWrite(8, LOW);     //모터 A방향설정2
  analogWrite(9,0);       //모터 A속도조절(0~255)
  //모터 B설정
  digitalWrite(4,HIGH);
  digitalWrite(5,LOW);
  analogWrite(3,0);
  delay(delaytime);
}

void column_left_march (int speed)
{
  //모터 A설정
  digitalWrite(7, HIGH);    //모터 A방향설정1
  digitalWrite(8, LOW);     //모터 A방향설정2
  analogWrite(9,0);       //모터 A속도조절(0~255)
  //모터 B설정
  digitalWrite(4,HIGH);
  digitalWrite(5,LOW);
  analogWrite(3,speed);
  delay(delaytime);
}

void column_right_march (int speed)
{
  //모터 A설정
  digitalWrite(7, HIGH);    //모터 A방향설정1
  digitalWrite(8, LOW);     //모터 A방향설정2
  analogWrite(9,speed);       //모터 A속도조절(0~255)
  //모터 B설정
  digitalWrite(4,HIGH);
  digitalWrite(5,LOW);
  analogWrite(3,0);
  delay(delaytime);
}

void forward_march (int speed)
{
  //모터 A설정
  digitalWrite(7, HIGH);    //모터 A방향설정1
  digitalWrite(8, LOW);     //모터 A방향설정2
  analogWrite(9,speed);       //모터 A속도조절(0~255)
  //모터 B설정
  digitalWrite(4,HIGH);
  digitalWrite(5,LOW);
  analogWrite(3,speed);
  // 가장 중요한 DELAY를 놓쳤어 이걸 안쓰니까 안돌아간듯?
  delay(delaytime);
}

void loop()
{
  // lower IR_value means that the sensor meets white color.
  // IR_output1 is left sensor value
  // IR_output2 is middle sensor value
  // IR_output3 is right sensor value.
  
  int IR_value1 = analogRead(IR_output1);
  int IR_value2 = analogRead(IR_output2);
  int IR_value3 = analogRead(IR_output3); 

  unsigned int IR1_over = IR_value1 > threshold ? 0 : 1 << 0;
  unsigned int IR2_over = IR_value2 > threshold ? 0 : 1 << 1;
  unsigned int IR3_over = IR_value3 > threshold ? 0 : 1 << 2;  

  unsigned int sensor_status = (IR1_over ^ IR2_over) ^ IR3_over;
  
  // swap lower 3 bits because black tape is too bright than white paper.
  // if the line is darker than background, please comment below line.
  //sensor_status = sensor_status ^ 7;

  // DEBUG POINT
  if(COUNT > COUNT_THRESHOLD)
  {
    Serial.println(sensor_status);
    Serial.println(IR_value1);
    Serial.println(IR_value2);
    Serial.println(IR_value3);
    Serial.println(1111111111);
    COUNT = 0;
  } 
  else 
  {
    ++COUNT;
  }
  
  
  switch (sensor_status)
  {
    case 0:
      // STOP
      stop_march();
      break;
      
    case 1:
      // TURN RIGHT 
      column_right_march(100);
      break;
      
    case 2:
      // FORWARD
      forward_march(200);
      break;

    case 3:
      // TURN RIGHT
      column_right_march(120);
      break;

    case 4:
      // TURN LEFT
      column_left_march(100);
      break;

    case 5:
      // STOP
      stop_march();
      break;

    case 6:
      // TURN LEFT
      column_left_march(120);
      break;

    case 7:
      stop_march();
      break;

    default:
      stop_march();
  }
}