Measure distance with HC-SR04 and display on OLED using ESP32

esp32_distance_measurement_with_OLED.ino

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define ledPin 2
#define trigPin 5
#define echoPin 18
#define buzzerPin 19

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

Adafruit_SSD1306 oled(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

const float soundSpeed = 0.034; //

void setup() {
  Serial.begin(115200); // ใช้ความเร็วสูงขึ้น
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(buzzerPin, OUTPUT);

  if( !oled.begin(SSD1306_SWITCHCAPVCC, 0x3C) ) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  oled.clearDisplay();
  oled.setTextSize(2);
  oled.setTextColor(SSD1306_WHITE);
  oled.setCursor(0, 10);
  oled.println("Ready");
  oled.display();
  delay(1000);
}

void loop() {
  float duration_us, distance_cm;

  // ส่งสัญญาณ Trigger
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration_us = pulseIn(echoPin, HIGH);

  // คำนวณระยะทาง
  distance_cm = duration_us * soundSpeed /2;
  if (distance_cm < 10) {
    //turn buzzer on
    digitalWrite(buzzerPin, HIGH);
    digitalWrite(ledPin, HIGH);
  }else{
    //turn buzzer off
    digitalWrite(buzzerPin, LOW);
    digitalWrite(ledPin, LOW);
  }
  Serial.print("Distance:");
  Serial.print(distance_cm);
  //Serial.println(" cm");
  Serial.println(",");
  Serial.println(200);

  // แสดงบนจอ OLED
  oled.clearDisplay();
  oled.setTextSize(2);
  oled.setTextColor(SSD1306_WHITE);
  oled.setCursor(5,10);
  oled.print(distance_cm);
  oled.println(" cm");
  oled.display();
  delay(100);
}