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

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

#define OLED_RESET    -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

#define TRIG_PIN 2
#define ECHO_PIN 3

void setup() {
  Serial.begin(115200);

  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("No se encontró pantalla OLED"));
    while (true);
  }

  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.println("Sensor Ultrasonico");
  display.display();
  delay(1000);
}

void loop() {
  long duration;
  float distance;

  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  duration = pulseIn(ECHO_PIN, HIGH, 30000);
  distance = duration * 0.034 / 2;

  display.clearDisplay();
  display.setCursor(0, 0);

  if (duration == 0) {
    display.println("No hay respuesta");
    Serial.println("No response from sensor");
  } else {
    display.print("Distancia: ");
    display.print(distance);
    display.println(" cm");

    Serial.print("Distance: ");
    Serial.print(distance);
    Serial.println(" cm");
  }

  display.display();
  delay(500);
}