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

Q: In this project the implementation of code for “Measuring distance of an object using ultrasonic distance sensor (28015 Ping) and also smoothen the sensor data using moving average filter”.

A:

COMPONENTS:

<!-- [if !supportLists]-->1.       <!--[endif]-->ARDUINO UNO

<!-- [if !supportLists]-->2.       <!--[endif]-->ULTRASONIC DISTANCE SENSOR 28015 PING

<!-- [if !supportLists]-->3.       <!--[endif]-->JUMPER WIRES

CONNECTIONS:

<!-- [if !supportLists]-->1.       <!--[endif]-->SENSOR 5V PIN IS CONNECTED TO THE 5V OF ARDUINO

<!-- [if !supportLists]-->2.       <!--[endif]-->SENSOR GND PIN IS CONNECTED TO THE GND OF ARDUINO

<!-- [if !supportLists]-->3.       <!--[endif]-->SENSOR SIG PIN IS CONNECTED TO THE DIGITAL PIN 9

CODE:

#define WINDOW_SIZE 7

int inches = 0;

int cm = 0;

int INDEX = 0;

int VALUE = 0;

int SUM = 0;

int READINGS[WINDOW_SIZE] = {0}; // Initialize READINGS array

int AVERAGED = 0;

long readUltrasonicDistance(int triggerPin, int echoPin) {

  pinMode(triggerPin, OUTPUT);

  digitalWrite(triggerPin, LOW);

  delayMicroseconds(2);

  digitalWrite(triggerPin, HIGH);

  delayMicroseconds(10);

  digitalWrite(triggerPin, LOW);

  pinMode(echoPin, INPUT);

  return pulseIn(echoPin, HIGH);

}

void setup() {

  Serial.begin(9600);

}

void loop() {

  cm = 0.01723 * readUltrasonicDistance(9, 9);

  inches = cm / 2.54;

  SUM = SUM - READINGS[INDEX];

  VALUE = inches;

  READINGS[INDEX] = VALUE;

  SUM = SUM + VALUE;

  INDEX = (INDEX + 1) % WINDOW_SIZE;

  AVERAGED = SUM / WINDOW_SIZE;

  Serial.print("The distance is: ");

  Serial.println(inches);

  Serial.print("Filtered data is: ");

  Serial.println(AVERAGED * 100);

  delay(100);

}

EXPLANATION:

1. Global Variables:
• WINDOW_SIZE: This constant defines the number of readings to be averaged.
• inches and cm: Variables to store the distance measurement in inches and centimeters.
• INDEX: An index to keep track of the current position in the READINGS array.
• VALUE: Stores the most recent distance value.
• SUM: Keeps a running sum of the values in the READINGS array.
• READINGS: An array used to store the last WINDOW_SIZE distance measurements for averaging.
• AVERAGED: Stores the averaged distance value.
2. readUltrasonicDistance Function:
• This function is used to trigger the ultrasonic sensor, measure the echo time, and calculate the distance in centimeters based on the measured time. It takes two arguments: triggerPin and echoPin, which are used to connect the trigger and echo pins of the sensor.
3. setup Function:
• This function is called once at the start of the program. It initializes the serial communication with a baud rate of 9600, which is used for debugging and printing output to the serial monitor.
4. loop Function:
• The loop function is where the main functionality of the program occurs, and it runs continuously.
• It first triggers the ultrasonic sensor to measure the distance in centimeters (cm) using the readUltrasonicDistance function.
• It then converts the distance to inches and stores it in the inches variable.
• It updates the running sum SUM by subtracting the oldest reading from the READINGS array and adding the new VALUE.
• It updates the READINGS array at the current INDEX with the most recent VALUE.
• It calculates the averaged distance value (AVERAGED) by dividing the SUM by WINDOW_SIZE.
• It prints the current distance in inches and the averaged distance (multiplied by 100) to the serial monitor.
• It then adds a delay of 100 milliseconds to control the rate at which readings are taken.