EchoGuard: Your Personal Parking Assistant


Our assigment idea was sparked by a common scenario we all encounter – parking a car in reverse. In discussing the challenges of accurately judging the distance, my partner and I realized the potential hazards and the lack of a reliable solution. Considering how much we rely on the beeping sensor in our own cars for safe parking, we envisioned a solution to bring this convenience to everyone. Imagine a situation where you can’t live without that reassuring beep when you’re reversing. That’s precisely the inspiration behind our assigment – a beeping sensor and a light that mimics the safety we’ve come to depend on, implemented with a car toy to illustrate its practical application.

Required Hardware

– Arduino
– Breadboard
– Ultrasonic distance sensor
– Red LED
– 10k resistor
– Piezo speaker
– Jumper wires

Schematic Diagram

Circuit Diagram

Setting Up the Components

Ultrasonic Distance Sensor Connections:
VCC to 5V
TRIG to digital pin 9
ECHO to digital pin 10
GND to GND on the Arduino

Speaker Connections:
Positive side to digital pin 11
Negative side to GND

LED Connections:
Cathode to GND
Anode to digital pin 13 via a 10k resistor

Coding the Logic

// defines pins numbers
const int trigPin = 9;
const int echoPin = 10;
const int buzzerPin = 11;
const int ledPin = 13;

// defines variables
long duration;
int distance;
int safetyDistance;

// Define pitches for the musical notes
int melody[] = {262, 294, 330, 349, 392, 440, 494, 523}; 

void setup() {
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT);  // Sets the echoPin as an Input
  pinMode(buzzerPin, OUTPUT);
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600); // Starts the serial communication

void loop() {
  // Clears the trigPin
  digitalWrite(trigPin, LOW);

  // Sets the trigPin on HIGH state for 10 microseconds
  digitalWrite(trigPin, HIGH);
  digitalWrite(trigPin, LOW);

  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);

  // Calculating the distance
  distance = duration * 0.034 / 2;

  safetyDistance = distance;
  if (safetyDistance <= 5) {
    // Play a musical note based on distance
    int index = map(safetyDistance, 0, 5, 0, 7); // Map distance to array index
    tone(buzzerPin, melody[index]); // Play the note
    digitalWrite(ledPin, HIGH);
  } else {
    noTone(buzzerPin); // Stop the tone when not close
    digitalWrite(ledPin, LOW);

  // Prints the distance on the Serial Monitor
  Serial.print("Distance: ");


Hardware Implementation

Video Illustration (Initial idea with beeping sound)

Video Illustration 2 (using melody)

Working Explanation and Conclusion
The ultrasonic distance sensor measures the gap between the car and the sensor on the breadboard. When the distance diminishes below a predefined threshold (5 units in our design), the buzzer emits a warning sound, and the red LED illuminates, acting as a clear visual cue for the driver to halt. This Arduino-based system seamlessly combines hardware and software, offering an elegant solution to a common problem. In creating this assignment, we’ve not only simplified the process of reverse parking but also contributed to enhancing overall safety, turning our initial conversation into a tangible, practical innovation.

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