Nathan Pigott
autonomous toy car

Basically my project  is a car with a distance finder attached to the front. it is rotated side to side and finds the distance of the closest object. When said crossest object comes within 8 inches of the car it will reverse and turn away from the object.

My car works with a distance sensor which is attached to a servo motor which rotates to allow maximum field of view for the sensor. The code for the motors is basic, it says if object< 8 inches then reverse and turn if not continue to go forwards. I also added an if  statement to if object< 8 which reads what direction the object detected is and then reverses and turns away from that side.
The servo motor which rotates the distance senor is set to only rotate between 130 degrees and 40 degrees. I also have the serial monitor set up to give the exact distance of the closest object to the distance sensor.

This is a video of my car in action
https://www.youtube.com/watch?v=6dU_tAIY9S4

This is a video of my code
https://www.youtube.com/watch?v=pjddUQKHJnw



Problems I faced
There were many problems I faced. The motors did not run at the same speed when not on a full battery. My first 3D printed holder for my distance finder didn't work. I used a different motor shield at first and had to switch over to this new one so i could use my encoders. Then i didn't end up using the encoders. Many more problems happened but i always got past them.

What I would have done with more time.
I would have setup and got my encoders working so even on a low battery my car would drive in a strait line.

This is my code

//MOTORS

int RF = 8;

int RB = 7;

int LF = 6;

int LB = 5;

int speedr = 9;

int speedl = 10;

//DISTANCE FINDER

const int pwPin = 13;

long pulse, inches, cm;

//SERVO 

int servo = 2;

int heading = 90;

int dir = -5;

void setup() {

  //DISTANCE 

  Serial.begin(9600);

  //SERVO

  pinMode(2, OUTPUT);

   //MOTOR

  pinMode(RF,OUTPUT);

  pinMode(RB,OUTPUT);

  pinMode(LF,OUTPUT);

  pinMode(LB,OUTPUT);

  pinMode(speedr,OUTPUT);

  pinMode(speedl,OUTPUT);

  digitalWrite(speedr,HIGH);

  digitalWrite(speedl,HIGH);

  analogWrite (speedl, 255);

  analogWrite (speedr, 255);

}

void loop() {

  //DISTANCE

  pinMode(pwPin, INPUT); //uses distance finder as imput

  pulse = pulseIn(pwPin, HIGH);

  

  inches = pulse / 147; //147uS per inch

  cm = inches * 2.54;  //change inches to centimetres

  

  Serial.print(inches);// prints data from distance sensor 

  Serial.print("in, ");

  Serial.print(cm);

  Serial.print("cm");

  Serial.println();

  delay(1);

  

  servoPulse(heading);

  delay(5);

  // read sensor

  heading+=dir;

  if (heading > 130 || heading <40)// the angle the servo monator is restricted to

  {

    dir=dir*-1; 

  }

   if(inches <= 8){ //runs if distase is less than 8 inches

    if(heading <= 90){ //if servo is pointing right then run this

      backwardsR (700);

    }

   else{ //if servo is pointing left then run this

    backwardsL (700);

   }

  }

  else{

    forwards(); //what runs if distance is more than 8 inches

    }

}

void servoPulse (int angle) // controls servo

{

 int pwm = (angle*11) + 500;      // Convert angle to microseconds

 digitalWrite(2, HIGH);

 delayMicroseconds(pwm);

 digitalWrite(2, LOW);

 delay(50);                   // Refresh cycle of servo

}

void backwardsR (int sec){// runs if less than 8 inches on left side 

  digitalWrite(RF,LOW);

  digitalWrite(LF, LOW);

  digitalWrite(RB,HIGH);

  digitalWrite(LB,HIGH);

  delay(sec);

  digitalWrite(RB,LOW);

  delay(sec);

  digitalWrite(LB,LOW);

  }

  void forwards(){

    digitalWrite(RF,HIGH);

    digitalWrite(LF,HIGH);

  }

  void backwardsL(int sec){ // rus if less than 8 inches on right side

    digitalWrite(RF,LOW);

  digitalWrite(LF, LOW);

  digitalWrite(LB,HIGH);

  digitalWrite(RB,HIGH);

  delay(sec);

  digitalWrite(LB,LOW);

  delay(sec);

  digitalWrite(RB,LOW);

    

  }