Three level Ultra security system using Arduino

ldr laser security

Today we are in a world where robbery has increased to a great extent. Hence there is a need to protect everything using a security system. Here is a small project on security system called ULTRA SECURITY SYSTEM which will be very useful.

This system is three way protected and consists of three sensors which will alert the user in case if any attempt to breach occurs. For simplification i have explained the three parts of this Ultra security system individually. Let’s see what is that three level security.


This is the first level of detecting the robbery in BANK. LDR sensor is placed inside the locker the laser is focused on the door of the locker, When the robber tries to open the BANK cell the LDR in locker is light deviates and then the Arduino commands the GSM module then this sends a text message “ROBBERY” to the registered mobile number or the nearest police station.


  • LDR
  • GSM Module
  • NPN Transistors BC 547
  • Diodes (1N 4007)
  • Red LED
  • Capacitors (1 uF)
  • Voltage Regulator(7805)
  • Resistors
  • Batteries (9V)

 SCHEMATIC CIRCUIT:ldr arduino circuit


  1. #include <SoftwareSerial.h>
  2. SoftwareSerial mySerial(9,10); //(tx,rx) aurdino
  3. float a=A2;
  4. int b,c;
  5. void setup()
  6. {
  7. mySerial.begin(9600)// Setting the baud rate of GSM Module
  8. Serial.begin(9600)// Setting the baud rate of Serial Monitor
  9. delay(100);
  10. }
  11. void loop()
  12. {
  13. b=analogRead(a);
  14. c=map(b,0,1023,0,10);
  15. Serial.print(c);
  16. Serial.print(“/”);
  17. delay(1000);
  18. if(c<3)
  19. {
  20. mySerial.println(“AT+CMGF=1”)//Sets the GSM Module in Text Mode
  21. delay(1000)// Delay of 1000 milli seconds or 1 second
  22. mySerial.println(“AT+CMGS=\”+918500911427\”\r”);
  23. delay(1000);
  24. Serial.print(“ROBERRY”);
  25. mySerial.println(“ROBERRY”);
  26. delay(100);
  27. mySerial.println((char)26);// ASCII code of CTRL+Z
  28. delay(1000);
  29. }
  30. }

2)  LM35 LEVEL:

In this method if the robber tries to open the door by using any heating device like flame thrower. This LM35 heat sensor detects the heat and sends the message with the help of Arduino. It sends the command to the gsm module which will further send a text message as “ROBBERY” on the registered mobile number or if it can be contact to nearest police station.


  • Arduino Uno
  • GSM Module
  • LM35 Sensor

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