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Lesson 71: Measure distance and display on LCD screen | Arduino Step By Step Course

This project demonstrates how to combine an HC-SR04 ultrasonic sensor with an LCD1602 display to measure and display distances on the Arduino. This setup is useful for various applications requiring proximity detection and visual feedback.

Practical Applications:

• Robotics: Measuring distances for obstacle avoidance or navigation.
• Parking Assistance: Creating a simple parking distance sensor.
• Home Automation: Building a proximity-based lighting system.
• Industrial Automation: Monitoring distances in manufacturing processes.

Hardware/Components

To build this project, you will need the following components:

• Arduino Uno (or compatible board)
• HC-SR04 Ultrasonic Sensor
• LCD 1602 Display (I2C version recommended)
• Jumper Wires

Wiring Guide

The wiring is described in the video (in video at 00:31). The key connections are:

• Ultrasonic Sensor: VCC to 5V, GND to GND, TRIG to pin 12, ECHO to pin 11.
• LCD 1602: VCC to 5V, GND to GND, SDA to pin A4, SCL to pin A5.

%%WIRING%%

Code Explanation

The code utilizes the NewPing library for ultrasonic distance measurement and the LiquidCrystal_I2C library for LCD control (in video at 02:15). The key configurable parameters are:

#define TRIGGER_PIN  12  // Arduino pin tied to trigger pin on the ultrasonic sensor.
#define ECHO_PIN     11  // Arduino pin tied to echo pin on the ultrasonic sensor.
#define MAX_DISTANCE 200 // Maximum distance we want to ping for (in centimeters).
// Set the LCD address to 0x3F for a 16 chars and 2 line display
LiquidCrystal_I2C lcd(0x3F, 16, 2);
int VCC2 = 2; //extra VCC for LCD

The TRIGGER_PIN and ECHO_PIN define the Arduino pins connected to the ultrasonic sensor. MAX_DISTANCE sets the maximum measurable distance. The LCD address (0x3F) might need adjustment depending on your specific LCD module. The VCC2 pin provides an additional 5V supply for the LCD.

The sonar.ping_cm() and sonar.ping_in() functions are used to obtain distance measurements in centimeters and inches respectively (in video at 05:27 and 06:01).

Live Project/Demonstration

A demonstration of the project is shown in the video (in video at 06:42). The video shows the sensor measuring distances to various objects and displaying the results in centimeters and inches on the LCD screen. The serial monitor displays the same measurements, providing a means to verify the readings.

Chapters

• [00:04] Introduction and Project Overview
• [00:31] Wiring Diagram and Connections
• [02:15] Code Explanation: Ultrasonic Sensor Setup
• [03:19] Code Explanation: LCD1602 Setup
• [04:21] Code Explanation: Arduino Setup
• [04:46] Code Explanation: Main Loop and Display
• [06:42] Live Demonstration
• [07:26] Conclusion

/*
 * S08-03  
 * 使用LCD1602-I2C和HC-SR04超声波传感器与Arduino  
 * 由Ahmad Shamshiri为Robojax（Robojax.com）撰写/更新  
 * 日期：2019年1月16日，15:51，地点：加拿大安大略省阿贾克斯  
 * 
 * 此代码“按现状”提供，不附带任何担保或责任。只要您保留此说明，便可自由使用。*  
 * 此代码已从Robojax.com下载  
 * 此程序是自由软件：您可以根据自由软件基金会发布的GNU通用公共许可证的条款重新分发和/或修改该程序，许可证版本为3，或（根据您的选择）任何较新版本。  
 * 
 * 此程序的发布寄希望于它将会有用，  
 * 但不附带任何担保；甚至没有关于适销性或适合特定目的的隐含担保。有关更多详细信息，请参见GNU通用公共许可证。  
 * 
 * 您应该已经收到了GNU通用公共许可证的副本  
 * 与此程序一起。如果没有，请访问<https://www.gnu.org/licenses/>。
 */
#include <NewPing.h>

#define TRIGGER_PIN  12 // Arduino pin tied to trigger pin on the ultrasonic sensor.
#define ECHO_PIN     11 // Arduino pin tied to echo pin on the ultrasonic sensor.
#define MAX_DISTANCE 200 // Maximum distance we want to ping for (in centimeters). Maximum sensor distance is rated at 400-500cm.

NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); // NewPing setup of pins and maximum distance.

 // start of settings for LCD1602-I2C
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
 // Set the LCD address to 0x3F for a 16 chars and 2 line display
LiquidCrystal_I2C lcd(0x3F, 16, 2);
int VCC2 = 2;
 // end of settings for LCD1602-I2C

void setup() {
  Serial.begin(9600); // Open serial monitor at 19600 baud to see ping results.

  pinMode(VCC2, OUTPUT); // extra VCC for LCD
  digitalWrite(VCC2, HIGH); // extra VCC is now HIGH (5V)
 // initialize the LCD,
  lcd.begin();
 // Turn on the blacklight and print a message.
  lcd.backlight();
  lcd.clear();
  lcd.setCursor (0,0);
  lcd.print("Robojax LCD1602");

}

void loop() {
  delay(50); // Wait 50ms between pings (about 20 pings/sec). 29ms should be the shortest delay between pings.
   lcd.clear(); // clearn previous values from screen
  lcd.setCursor (0,0); // character zero, line 1
  lcd.print("LCD1602 HC-SR04"); // print text

 // print distance in cm
  lcd.setCursor (0,1); // character 0, line 2
  lcd.print(sonar.ping_cm()); // print distance in cm
  lcd.setCursor (3,1); // character 4, line 2
  lcd.print("cm"); // print "cm" on the display

 // print distance in inch
  lcd.setCursor (7,1); // character 8, line 2
  lcd.print(sonar.ping_in()); // print distance in cm
  lcd.setCursor (9,1); // character 4, line 2
  lcd.print("inches"); // print "cm" on the display

  Serial.print("Ping: ");
  Serial.print(sonar.ping_cm()); // Send ping, get distance in cm and print result (0 = outside set distance range)
  Serial.print("cm");
  Serial.print(", ");
  Serial.print(sonar.ping_in());
  Serial.println("in");
  int distance = sonar.ping_cm();

}