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

#define widthSize 128
#define heightSize 64

Adafruit_SSD1306 screenUnit(widthSize, heightSize, &Wire, -1);

int greenLamp = 2;
int yellowLamp = 3;
int redLamp = 4;
int soundAlert = 5;
int triggerPin = 6;
int echoPin = 7;

long waveDuration;
int objectDistance;

void setup() {
  pinMode(greenLamp, OUTPUT);
  pinMode(yellowLamp, OUTPUT);
  pinMode(redLamp, OUTPUT);
  pinMode(soundAlert, OUTPUT);
  pinMode(triggerPin, OUTPUT);
  pinMode(echoPin, INPUT);

  screenUnit.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  screenUnit.clearDisplay();
}

void loop() {

  digitalWrite(greenLamp, HIGH);
  digitalWrite(yellowLamp, LOW);
  digitalWrite(redLamp, LOW);
  delay(10000);

  digitalWrite(greenLamp, LOW);
  digitalWrite(yellowLamp, HIGH);
  digitalWrite(redLamp, LOW);
  delay(10000);

  digitalWrite(greenLamp, LOW);
  digitalWrite(yellowLamp, LOW);
  digitalWrite(redLamp, HIGH);

  unsigned long redTimer = millis();
  while (millis() - redTimer < 10000) {

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

    waveDuration = pulseIn(echoPin, HIGH);
    objectDistance = waveDuration * 0.034 / 2;

    if (objectDistance < 10) {
      digitalWrite(soundAlert, HIGH);
      screenUnit.clearDisplay();
      screenUnit.setTextSize(1);
      screenUnit.setTextColor(WHITE);
      screenUnit.setCursor(0, 20);
      screenUnit.println("Red Light Crossed");
      screenUnit.display();
    } else {
      digitalWrite(soundAlert, LOW);
      screenUnit.clearDisplay();
      screenUnit.display();
    }
  }

  digitalWrite(redLamp, LOW);
}