Density-Based Smart Traffic Light System with Emergency Vehicle Priority

Educational Notes

This project is designed to be accessible to students from Class 4 to Masters level, with complexity scalable to match different age groups and skill levels.

Learning Objectives:

• Understand basic electronics and circuitry principles
• Learn sensor applications and data collection techniques
• Develop problem-solving skills through hands-on building and troubleshooting
• Apply programming concepts to control hardware and process data
• Connect projects to real-world Nepalese contexts and challenges

Adaptability:

• For younger students (Class 4-8): Focus on assembling pre-built circuits, observing results, and understanding basic concepts
• For intermediate students (Class 9-12): Modify code, experiment with parameters, and explore underlying principles
• For advanced students (Undergraduate/Masters): Optimize designs, add features, conduct research extensions, and analyze performance

Safety Note: Always supervise younger students when working with electricity, heat, or moving parts.

Create a smart intersection model that dynamically allocates green light timing and grants override to ambulances via RC522 RFID.

Hardware Bill of Materials:

• Microcontroller: UNO R3 ATMEGA328P-PU Development Board with 30cm cable
• Indicators: LED 5mm Red, Green, Yellow Pack
• RFID Reader: HS-S62-L RC522 NFC RFID Reader Writer Module 13.56MHz
• Alarm & Power: Active Buzzer + 9v 1A Power Supply Adapter

Circuit Pinout & Wiring Connections:

Firmware Source Code (Arduino Mega 2560 C++)

#include <Wire.h>
#include <EEPROM.h>
#include <SPI.h>
#include <MFRC522.h>

#define SS_PIN 5
#define RST_PIN 22
MFRC522 rfid(SS_PIN, RST_PIN);

const char* ssid = "GhumtiPasal_WiFi";
const char* pass = "NepalMakers2026";

void setup() {
  Serial.begin(9600);
  SPI.begin();
  rfid.PCD_Init();
  Serial.println("RFID Contactless Reader Ready. Tap Card...");
  
}

void loop() {
  if (!rfid.PICC_IsNewCardPresent() || !rfid.PICC_ReadCardSerial()) {
    delay(50);
    return;
  }

  String cardUID = "";
  for (byte i = 0; i < rfid.uid.size; i++) {
    cardUID += String(rfid.uid.uidByte[i] < 0x10 ? "0" : "");
    cardUID += String(rfid.uid.uidByte[i], HEX);
  }
  cardUID.toUpperCase();

  Serial.println("Scanned Card UID: " + cardUID);
  Serial.println("Access Granted! Syncing record with database...");
  rfid.PICC_HaltA();
  rfid.PCD_StopCrypto1();
  delay(2000);
}