CIPAD Leçon 20: Radar de recul ultrasonic avec alarme de proximité

Introduction

In this tutorial, we will learn how to create an ultrasonic reverse radar system with a proximity alarm using Arduino. This project builds on concepts introduced in previous lessons and combines a few lines of code with a piezo buzzer to detect distance and provide warnings. This guide is perfect for beginners looking to expand their Arduino programming skills and create practical applications.

Step 1: Gather Your Materials

Before starting, ensure you have the following components:

• Arduino board (e.g., Arduino Uno)
• Ultrasonic distance sensor (HC-SR04)
• Piezo buzzer
• Breadboard and jumper wires
• Power source (USB or battery)

Practical Tips

• A breadboard will help you easily connect components without soldering.
• Make sure your ultrasonic sensor and piezo buzzer are compatible with your Arduino model.

Step 2: Connect the Components

Follow these connections to set up your circuit:

1. Connect the ultrasonic sensor to the Arduino:
   • VCC to 5V
   • GND to GND
   • Trigger pin to digital pin 9
   • Echo pin to digital pin 10
2. Connect the piezo buzzer:
   • One terminal to digital pin 8
   • Other terminal to GND

Common Pitfalls to Avoid

• Double-check your pin connections to avoid incorrect readings.
• Ensure the ultrasonic sensor is oriented correctly for distance measurement.

Step 3: Write the Arduino Code

Use the following code to program your Arduino for distance measurement and alarm functionality:

#include <NewPing.h>

#define TRIGGER_PIN 9
#define ECHO_PIN 10
#define MAX_DISTANCE 200
#define BUZZER_PIN 8

NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);

void setup() {
    pinMode(BUZZER_PIN, OUTPUT);
    Serial.begin(9600);
}

void loop() {
    delay(50);
    unsigned int distance = sonar.ping_cm();
    Serial.print("Distance: ");
    Serial.print(distance);
    Serial.println(" cm");

    if (distance > 0 && distance < 30) {
        digitalWrite(BUZZER_PIN, HIGH); // Activate buzzer
    } else {
        digitalWrite(BUZZER_PIN, LOW); // Deactivate buzzer
    }
}

Explanation of Code

• The code uses the NewPing library to handle the ultrasonic sensor.
• It defines pins for the trigger, echo, and buzzer.
• The loop checks the distance and activates the buzzer if the distance is below 30 cm.

Step 4: Upload the Code and Test

1. Connect your Arduino to your computer using a USB cable.
2. Open the Arduino IDE and copy the code above into a new sketch.
3. Select your Arduino board and port under the Tools menu.
4. Click the upload button to transfer the code to your Arduino.
5. After uploading, disconnect the USB and power the Arduino using a battery or external power.

Testing Your Setup

• Place an object in front of the ultrasonic sensor at varying distances.
• Ensure the buzzer activates when the object is within 30 cm.

Conclusion

You have successfully created an ultrasonic reverse radar with a proximity alarm using Arduino! This project enhances your understanding of sensor integration and coding in Arduino. As a next step, consider experimenting with different distance thresholds or adding additional features, such as LED indicators or a display for distance readouts. Happy coding!