Project 2 - Measuring the distance of an object using ultrasonic sensor and also smoothen the sensor data using moving average filter

const int numReadings = 10;

int readings[numReadings]={0}; // the readings from the analog input
int readIndex = 0; // the index of the current reading
int total = 0; // the running total
int average = 0; // the average
int cm = 0;

long readUltrasonicDistance(int triggerPin, int echoPin)
{
pinMode(triggerPin, OUTPUT); // Clear the trigger
digitalWrite(triggerPin, LOW);
delayMicroseconds(2);

// Sets the trigger pin to HIGH state for 10 microseconds
digitalWrite(triggerPin, HIGH);
delayMicroseconds(10);
digitalWrite(triggerPin, LOW);
pinMode(echoPin, INPUT);

// Reads the echo pin, and returns the sound wave travel time in microseconds
return pulseIn(echoPin, HIGH);
}

void setup()
{
Serial.begin(9600);

}

void loop()
{
// subtract the last reading:
total = total - readings[readIndex];

// measure the ping time in cm
readings[readIndex] = 0.01723 * readUltrasonicDistance(7, 7);

// add the reading to the total:
total = total + readings[readIndex];

// advance to the next position in the array:
readIndex = readIndex + 1;

// if we're at the end of the array...
if (readIndex >= numReadings) {
// ...wrap around to the beginning:
readIndex = 0;
}

// calculate the Moving Average filter:
average = total / numReadings;

Serial.print(average );
Serial.println("cm");
delay(100); // Wait for 100 millisecond(s)
}