S2E7_ultrasonic_drive_to_wall_upgrade.ino

/*
Challenges:
1) create ultrasonic function that returns distance in cm
2) make sure that function works
3) create moveToWall function
4) when you stop, back up and turn around
5) once you see a wall, stop, back up and turn around.. and keep going looking for walls

*/

int motb_pin1 = 3;
int motb_pin2 = 11;

int mota_pin1 = 9;
int mota_pin2 = 10;

int button_pin = 2;

int trig_pin = 4;
int echo_pin = 5;

void setup() {
  
  //-Control Motor B
  pinMode(motb_pin1,OUTPUT);
  pinMode(motb_pin2,OUTPUT);
  
  //-Control Motor A
  pinMode(mota_pin1,OUTPUT);
  pinMode(mota_pin2,OUTPUT);
  
  //- button
  pinMode(button_pin,INPUT_PULLUP);
  
  //-ultrasonic pin
  pinMode(trig_pin,OUTPUT);
  pinMode(echo_pin,INPUT);
  
  Serial.begin(9600);
  
}

//-sends sound out and receives sound
//-returns the distance in centimeters
int ultrasonic() {
  
  long time;
  float distance;
  
  //-trigger a sound 
  // send out trigger signal
  digitalWrite(trig_pin, LOW);
  delayMicroseconds(2);
  digitalWrite(trig_pin, HIGH);
  delayMicroseconds(20);
  digitalWrite(trig_pin, LOW);
  
  //- a sound has gone out!!
  //- wait for a sound to come back
  
  time = pulseIn(echo_pin, HIGH);
  
  //- calculate the distance in centimeters
  distance = 0.01715 * time;
  
  return distance;

}

//- turn 90 degrees
void turnRight() {
  
  //- motor b is stopped
  analogWrite(motb_pin1,0);
  analogWrite(motb_pin2,0);
  
  //- motor a moves forward
  analogWrite(mota_pin1,255);
  analogWrite(mota_pin2,0);
  
  delay(600);
  
  //- stop motor a
  analogWrite(mota_pin1,0);
  analogWrite(mota_pin2,0);
  
}

void tankTurn(int speeda, int speedb) {
  //- motor a moves ... backwards
  analogWrite(mota_pin1,0);
  analogWrite(mota_pin2,speeda);
  
  //- motor b moves forward
  analogWrite(motb_pin1,0);
  analogWrite(motb_pin2,speedb);
  
  delay(1650);
  
  //- stop both motors
  stop();
  
}

void turnAround(int speeda, int speedb) {
  
  //- motor a is stopped
  analogWrite(mota_pin1,0);
  analogWrite(mota_pin2,0);
  
  //- motor b moves forward
  analogWrite(motb_pin1,0);
  analogWrite(motb_pin2,speedb);
  
  delay(1650);
  
  //- stop motor b
  analogWrite(motb_pin1,0);
  analogWrite(motb_pin2,0);
  
}

void turnLeft() {
  
  //- motor a is stopped
  analogWrite(mota_pin1,0);
  analogWrite(mota_pin2,0);
  
  //- motor b moves forward
  analogWrite(motb_pin1,0);
  analogWrite(motb_pin2,255);
  
  delay(800);
  
  //- stop motor b
  analogWrite(motb_pin1,0);
  analogWrite(motb_pin2,0);
  
}

void stop() {
  //- motor a
  analogWrite(mota_pin1,255);
  analogWrite(mota_pin2,255);
  
  //- motor b
  analogWrite(motb_pin1,255);
  analogWrite(motb_pin2,255);
}


void moveToWall(int speeda, int speedb) {
  
  //- move forward!
  //- motor a
  analogWrite(mota_pin1,speeda);
  analogWrite(mota_pin2,0);
  
  //- motor b
  analogWrite(motb_pin1,0);
  analogWrite(motb_pin2,speedb);
  
  //-stop when you hit a wall!!
  
  int distance = ultrasonic();
  
  while (distance > 5) {
    //-do nothing except check distance
    distance = ultrasonic();
  }
  
  //-stop!!!
  stop();
  
}


void moveForward(int speeda, int speedb, int inches) {
  
  int myDelay;
  
  //- motor a
  analogWrite(mota_pin1,speeda);
  analogWrite(mota_pin2,0);
  
  //- motor b
  analogWrite(motb_pin1,0);
  analogWrite(motb_pin2,speedb);
  
  //- move forward the distance in inches
  
  
  
  myDelay = inches*125;
  delay(myDelay);
  
  //- stop
  stop();
  
}

void moveBackward(int speeda, int speedb) {
  
  //- motor a
  analogWrite(mota_pin1,0);
  analogWrite(mota_pin2,speeda);
  
  //- motor b
  analogWrite(motb_pin1,speedb);
  analogWrite(motb_pin2,0);
  
}



void loop() {
  
  Serial.println(ultrasonic());
  
  delay(100);
  
  
  if (digitalRead(button_pin)==LOW) {
      
      //- move to the wall first
      moveToWall(120,120);
      
      delay(1000);
      
      //- back up a little 
      moveBackward(120,120);
      
      delay(400);
      
      //- stop
      stop();
      
      delay(1000);
      
      //- turn around
      tankTurn(120,120);
      
      
  }
  else {
    stop();
  }

}