Autonomous Remote Control (RC) Car

const int turnOnMotorPin = 11;
const int controlMotorPin_1 = 12;
const int controlMotorPin_2 = 10;
const int turnMotor_1 = 9;
const int turnMotor_2 = 8;
const int echoSensor = 7;
const int triggerSensor = 6;

int motion = 1; //forward
int direction = 0; // straight


void setup() {
  pinMode(controlMotorPin_1, OUTPUT);
  pinMode(controlMotorPin_2, OUTPUT);
  pinMode(turnOnMotorPin, OUTPUT);
  pinMode(turnMotor_1, OUTPUT);
  pinMode(turnMotor_2, OUTPUT);
  pinMode(echoSensor,INPUT);
  pinMode(triggerSensor,OUTPUT);
  digitalWrite(turnOnMotorPin, HIGH);
  
  delay(5000); // Some initial delay to place the car in the right location

}

void loop() {
  

  long duration, inches;
  digitalWrite(triggerSensor, LOW);
  delayMicroseconds(2);
  digitalWrite(triggerSensor, HIGH);
  delayMicroseconds(10);
  digitalWrite(triggerSensor, LOW);
  pinMode(echoSensor, INPUT);
  duration = pulseIn(echoSensor, HIGH);
  inches = microsecondsToInches(duration);

  int oldMotion = motion;

  if(motion == 1 && inches > 15){
    forward();
    motion = 1;
  }else
  if(motion == 1 && inches <= 15){
    reverse();
    motion = 0;
  }else if(motion == 0 && inches <= 30) {
    reverse();
    motion = 0;
  }else if(motion == 0 && inches > 30){
    forward();
    motion = 1;
  }else {
    forward();
    motion = 1;
  }

  if(oldMotion != motion){
    direction = random(0, 2);
  }

  if(direction == 0){
    goStragith();
  }else if(direction == 1){
    changeDirectionLeft();
  }else {
    changeDirectionRight();
  }
  

  
  delay(100);
}

void changeDirectionLeft(){
  
      digitalWrite(turnMotor_1, HIGH);
      digitalWrite(turnMotor_2, LOW);
}

void changeDirectionRight(){
  
      digitalWrite(turnMotor_1, LOW);
      digitalWrite(turnMotor_2, HIGH);
}
void goStragith(){
  
      digitalWrite(turnMotor_1, LOW);
      digitalWrite(turnMotor_2, LOW);
}

void stop(){
    digitalWrite(controlMotorPin_1, LOW);
    digitalWrite(controlMotorPin_2, LOW);
}

void forward(){
    digitalWrite(controlMotorPin_1, HIGH);
    digitalWrite(controlMotorPin_2, LOW);
}

void reverse(){
    digitalWrite(controlMotorPin_1, LOW);
    digitalWrite(controlMotorPin_2, HIGH);
}

long microsecondsToInches(long microseconds)
{
  return microseconds / 74 / 2;
}