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

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

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

#define TRIG 9
#define ECHO 10

Servo gate;

long duration;
int distance;

void setup() {
  pinMode(TRIG, OUTPUT);
  pinMode(ECHO, INPUT);

  gate.attach(6);
  gate.write(0);

  Serial.begin(9600);

  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("OLED gagal");
    for(;;);
  }

  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(WHITE);
}

int getDistance() {
  digitalWrite(TRIG, LOW);
  delayMicroseconds(2);
  
  digitalWrite(TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG, LOW);

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

  return distance;
}

void loop() {
  int jarak = getDistance();
  Serial.println(jarak);

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

  if (jarak < 200) {
    gate.write(90);
    display.println("MASUK");
    display.println("Silakan");
  } else {
    gate.write(0);
    display.println("TIDAK ADA");
    display.println("KENDARAAN");
  }

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