#include <Servo.h>
Servo myservo;
const int numOfReadings = 10;                   // number of readings to take/ items in the array
int readings[numOfReadings];                    // stores the distance readings in an array
int arrayIndex = 0;                             // arrayIndex of the current item in the array
int total = 0;                                  // stores the cumlative total
int averageDistance = 0;                        // stores the average value
int led = 13;
// setup pins and variables for SRF05 sonar device

int echoPin = 8;                               // SRF05 echo pin (digital 2)
int initPin = 7;                               // SRF05 trigger pin (digital 3)
unsigned long pulseTime = 0;                    // stores the pulse in Micro Seconds
unsigned long distance = 0;                     // variable for storing the distance (cm)

int motor1Pin1 = 3;                             // pin 2 on L293D
int motor1Pin2 = 4;                             // pin 7 on L293D                            // pin 1 on L293D
int motor2Pin1 = 5;                             // pin 10 on L293D
int motor2Pin2 = 6;                             // pin  15 on L293D                            // pin 9 on L293D
int speaker = 10;


void setup() {
  // set the motor pins as outputs:
  pinMode(motor1Pin1, OUTPUT);
  pinMode(motor1Pin2, OUTPUT);
 
  pinMode(motor2Pin1, OUTPUT);
  pinMode(motor2Pin2, OUTPUT);
  pinMode(10,OUTPUT);
  pinMode(0,INPUT);
  pinMode(1,INPUT);
  
  // set enablePins high so that motor can turn on:
  

  myservo.attach(9);
  myservo.write(90);
  delay(100);

  pinMode(initPin, OUTPUT);                     // set init pin 3 as output
  pinMode(echoPin, INPUT);                      // set echo pin 2 as input

  // create array loop to iterate over every item in the array

  for (int thisReading = 0; thisReading < numOfReadings; thisReading++) {
    readings[thisReading] = 0;
  }
}

void loop() {
  digitalWrite(initPin, HIGH);                  // send 10 microsecond pulse
  delayMicroseconds(10);                                // wait 10 microseconds before turning off
  digitalWrite(initPin, LOW);                   // stop sending the pulse
  pulseTime = pulseIn(echoPin, HIGH);           // Look for a return pulse, it should be high as the pulse goes low-high-low
  distance = pulseTime/58;                      // Distance = pulse time / 58 to convert to cm.
  total= total - readings[arrayIndex];          // subtract the last distance
  readings[arrayIndex] = distance;              // add distance reading to array
  total= total + readings[arrayIndex];          // add the reading to the total
  arrayIndex = arrayIndex + 1;                  // go to the next item in the array                                 

  // At the end of the array (10 items) then start again
  if (arrayIndex >= numOfReadings)  {
    arrayIndex = 0;
  }

  averageDistance = total / numOfReadings;      // calculate the average distance
  delay(10);

  // check the average distance and move accordingly

  if (averageDistance <= 10){
    // go backwards
    digitalWrite(motor1Pin1, HIGH);
    digitalWrite(motor1Pin2, LOW);
    digitalWrite(motor2Pin1, HIGH);
    digitalWrite(motor2Pin2, LOW);
    digitalWrite(10,LOW);
    myservo.write(10);
    delay(100);    

  } 

  if (averageDistance <= 25 && averageDistance > 10) {
    // turn
    digitalWrite(motor1Pin1, HIGH);
    digitalWrite(motor1Pin2, LOW);
    digitalWrite(motor2Pin1, LOW);
    digitalWrite(motor2Pin2, HIGH);
    myservo.write(150);
    delay(100);   
  }

   
   if (averageDistance > 25)   {
    // go forward
    digitalWrite(motor1Pin1, LOW);
    digitalWrite(motor1Pin2, HIGH);
    digitalWrite(motor2Pin1, LOW);
    digitalWrite(motor2Pin2, HIGH); 
    digitalWrite(10,LOW); 
    myservo.write(90);
    delay(100);   

  }
 
}