SR04 Ultrasonic Distance Alarm

Introduction

1. When the circuit is activated, SR04 continuously measures the distance and displays the detected value in real time on LCD1602.

2. When the ultrasonic distance measurement is less than 50cm, the LED flashes; when it is greater than 50cm, the LED does not flash.

3. When the ultrasonic distance measurement exceeds 200cm, the LCD will not display anything.

3D Online Simulation

Description

#include <LiquidCrystal.h>

// Initialize LCD1602

LiquidCrystal lcd(7, 6, 5, 4, 3, 2);

// Define pins

const int trigPin = 9;

const int echoPin = 10;

const int ledPin = 8;

void setup() {

// Initialize serial communication

Serial.begin(9600);

// Initialize LCD1602

lcd.begin(16, 2);

// Set TRIG and ECHO pins as output and input

pinMode(trigPin, OUTPUT);

pinMode(echoPin, INPUT);

pinMode(ledPin, OUTPUT);

}

void loop() {

// Clear LCD display

lcd.clear();

// Send a 10us pulse to the TRIG pin

digitalWrite(trigPin, LOW);

delayMicroseconds(2);

digitalWrite(trigPin, HIGH);

delayMicroseconds(10);

digitalWrite(trigPin, LOW);

// Read the pulse time from the ECHO pin

long duration = pulseIn(echoPin, HIGH);

// Calculate the distance

float distance = (duration / 2) * 0.0343;

// Display the distance

lcd.print("Dist:");

lcd.print(distance);

lcd.print(" cm");

// Control the LED

if (distance < 50) {

digitalWrite(ledPin, HIGH);

} else {

digitalWrite(ledPin, LOW);

}

// If the distance is greater than 200cm, do not display

if (distance > 200) {

lcd.clear();

}

// Delay

delay(500);

}

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