Laser Tripwire (Smart Internal Resistor Mode)

What It Does (Yeh Kya Karta Hai?)

Kya aapne kabhi movies mein dekha hai ke kaise hero laser beams ke beech mein se guzarta hai? Aaj hum wahi system banayenge.

Laser Tripwire ek security system hai. Ismein ek Laser beam seedha LDR (Light Sensor) par girti hai. Jab tak laser light LDR par hai, sab okay hai. Lekin jaise hi koi chor ya intruder us laser line ko cross karta hai (beam toot-ti hai), Buzzer (Alarm) bajna shuru ho jata hai!

• Real World Use: Banks, Museums, aur High-Security areas mein use hota hai.

Components Required

• Microcontroller: Arduino Uno
• Laser Module
• LDR (Light Sensor)
• Buzzer
• Jumper Wires (M/M)

(Note: Koi alag se Resistor nahi chahiye)

Wiring (Taarein Jorna)

Wiring ab bahut simple hai. Hum LDR ko seedha Arduino se jor denge.

A. Laser Module:

• S (Signal/VCC): Arduino 5V
• – (GND): Arduino GND
• (Laser light seedhi LDR par girni chahiye)

B. LDR (Light Sensor) – Direct Connection:

• LDR ki Pehli Taang: Arduino GND
• LDR ki Dusri Taang: Arduino A0
• (Direction ka masla nahi, kisi bhi taang ko kahin bhi laga dein)

C. Buzzer (Alarm):

• Positive (+) lambi taang: Arduino Pin 9
• Negative (-) choti taang: Arduino GND

Code

Is code mein humne INPUT_PULLUP Command use ki hai, jo Arduino ka internal resistor on kar deti hai.

Logic Change:

• Jab Laser LDR par hogi -> Value KAM (Low) hogi.
• Jab Laser tootegi (Andhera hoga) -> Value ZYADA (High) hogi -> Alarm Bajega

/*
 * Project 11: Smart Laser Tripwire (No External Resistor)
 * Platform: PlzPapa Robotic Kit
 */

const int ldrPin = A0;      // LDR sensor pin
const int buzzerPin = 9;    // Buzzer pin

// Sensitivity Setting
// Laser hatne par value barhegi. Agar value 500 se upar gayi to alarm bajega.
const int threshold = 500;  

void setup() {
  pinMode(buzzerPin, OUTPUT);
  
  // Yahan hum Arduino ka Internal Resistor ON kar rahe hain
  pinMode(ldrPin, INPUT_PULLUP); 
  
  Serial.begin(9600); // Value check karne ke liye
  
  // Start up beep
  digitalWrite(buzzerPin, HIGH);
  delay(100);
  digitalWrite(buzzerPin, LOW);
}

void loop() {
  int ldrValue = analogRead(ldrPin); // Sensor ki value parho
  
  // Serial Monitor par value dekhein (Tools > Serial Monitor)
  // Laser LDR par hone par value kam honi chahiye (10-100 ke beech)
  // Laser hatne par value barh jani chahiye (600-1000)
  Serial.print("Sensor Value: ");
  Serial.println(ldrValue);

  // Agar value threshold se ZYADA hai (Matlab laser toot gayi/andhera ho gaya)
  if (ldrValue > threshold) {
    digitalWrite(buzzerPin, HIGH); // Alarm ON
    delay(500); // Aadhe second ke liye
  } else {
    digitalWrite(buzzerPin, LOW);  // Sab safe hai
  }
  
  delay(50);
}