workshop car

workshop_car.ino

// connect the distance sensor
#define trigPin 13
#define echoPin 12

// connect motor controller pins to Arduino digital pins
// motor one
int enA = 3;
int in1 = 4;
int in2 = 5;
// motor two
int in3 = 6;
int in4 = 7;
int enB = 9;

void setup() {
  Serial.begin(9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);  

  // set all the motor control pins to outputs
  pinMode(enA, OUTPUT);
  pinMode(enB, OUTPUT);
  pinMode(in1, OUTPUT);
  pinMode(in2, OUTPUT);
  pinMode(in3, OUTPUT);
  pinMode(in4, OUTPUT);
}

void loop() {      
  if (getDistance() > 30) {
    moveForward();
  } else {
    turnUntilSafeDistanceAhead();
  }
}

long getDistance() {
  long duration, distance;
  digitalWrite(trigPin, LOW);  // Added this line
  delayMicroseconds(2); // Added this line
  digitalWrite(trigPin, HIGH);
  
  delayMicroseconds(10); // Added this line
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration/2) / 29.1;

  Serial.println(distance);

  return distance;
}

void turnUntilSafeDistanceAhead() {
  // move a bit forward and ask distance.
  digitalWrite(in1, HIGH);
  digitalWrite(in2, LOW);
  // set speed to 200 out of possible range 0~255
  analogWrite(enA, 255);
  // turn on motor B
  digitalWrite(in3, HIGH);
  digitalWrite(in4, LOW);
  // set speed to 200 out of possible range 0~255
  analogWrite(enB, 255);
}

void moveForward() {
  // move a bit forward and ask distance.
  digitalWrite(in1, HIGH);
  digitalWrite(in2, LOW);
  // set speed to 200 out of possible range 0~255
  analogWrite(enA, 255);
  // turn on motor B
  digitalWrite(in3, LOW);
  digitalWrite(in4, HIGH);
  // set speed to 200 out of possible range 0~255
  analogWrite(enB, 255);
}