A security alarm based on infrared radiations. 555 Timer used in this process. Comparator, Photodiode, Resistors, Capacitors, and Buzzer are used. Complete working Of circuit.

1. IR Based Security Alarm
Syed Hammad Ali Gillani
Department Of Physics
MAY
11,
2021
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2. Introduction Components
Working Conclusion
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3. INTRODUCTION
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4. IR Based Security Alarm
• The IR security alarm consists of:
IR sensors has to be placed opposite to each other.
This detect any human entry, obstacle, theft etc.
 Infrared IR Transmitter
 IR receiver
 Photodiode
 555 Timer
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5. A typical premises security alarm employs the following components:
a) Sensors:
Devices which detect interruptions.
b) Alerting devices:
Bells, sirens, and/or flashing lights.
c) Keypads:
Function as the human-machine interface to the system.
Feature indicator lights, a small multi-character display, or both.
Security Alarm
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IR Based Security Alarm

6. The portion of electromagnetic spectrum having wavelengths longer than visible
light wavelengths, but smaller than microwaves.
The region roughly from 700nm to 1 mm.
Emitted by objects with temperature above 0 kelvin.
Sensors that detect/measure infrared radiation or change in the radiation from
outer source or inbuilt source.
IR Sensors
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IR Based Security Alarm

7. • Which compares the two inputs that are applied to it
• And produces an output.
The output value indicates which of the inputs is greater or lesser.
EXAMPLE: Operational Amplifier
Comparator
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IR Based Security Alarm

8. Operational Amplifier
Inverting Comparator Non-Inverting Comparator
Comparator
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IR Based Security Alarm

9. Operational Amplifier
Inverting Comparator
Comparator
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IR Based Security Alarm

10. Operational Amplifier
Non-Inverting Comparator
Comparator
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IR Based Security Alarm

11. 555 TIMER
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IR Based Security Alarm

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IR Based Security Alarm
555 TIMER

13. 555 TIMER
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IR Based Security Alarm

14. Mono-Stable
555 TIMER
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IR Based Security Alarm

15. COMPONENTS
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16. Circuit Diagram
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IR Based Security Alarm

17. Apparatus
 IR pair (IR Land Photodiode)
 555 timer IC
 ED IC LM358
 Resistor 100, 10k, 100k, 330, 220 ohms
 Capacitor 10uF
 Variable resistor – 10k
 Buzzer
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IR Based Security Alarm

18. WORKING
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19. Explanation
IR LED emits IR radiation and photodiode detects the radiation.
Someone moves through this beam, IR rays stops falling on photodiode and Buzzer
start beeping.
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IR Based Security Alarm

20. Explanation
Op-amp LM358:
Two voltage comparators inside it, and we have used
one comparator here.
- end (PIN3) of voltage comparator is connected to the Photodiode and + end
(PIN 2) of voltage comparator is connected to a variable resistor of 10k.
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IR Based Security Alarm

21. Explanation
Voltage at + end of voltage comparator is higher than - end and the output of
the comparator is HIGH.
Comparator output is connected to the trigger PIN of the 555 timers, so when
the Trigger pin 2 is high, the 555 output is low.
During the period when the IR rays falls on Photodiode, the 555-timer output
remains LOW.
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IR Based Security Alarm

22. Explanation
When there is some movement, falling of IR rays on Photodiode gets interrupted.
Voltage at + end of voltage comparator becomes higher than – end.
Output of comparator LOW and makes the Trigger PIN 2 of 555 timer LOW. This
trigger the 555 timer, and 555 timer’s OUTPUT goes HIGH and Buzzer beeps.
Beep can be increased by changing the value of R1 or C1.
555 IC gets triggered when Trigger PIN 2 gets LOW.
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IR Based Security Alarm

23. Direction To Use
 Check the infrared led is glowing or not by using a camera.
 Alarm turns off after about 5-10 seconds of getting the contact with IR
again.
 Range of the circuit is about 5m.
 Vary the variable resistor to increase or decrease the intensity of the IR
LED for better performance in lighting conditions.
 Heat sinks should be used with the 7806 ICs or the IC may get damaged if
the circuit is powered on for a long time.
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IR Based Security Alarm

24. CONCLUSION
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25. Precautions
 The connection should be neat clean and tight.
 While completing the circuit we should remember of cathode and anode
terminal of IR LED, photodiode and Buzzer.
 All the components must be checked weather they are working or not.
 Distance between IR LED and photodiode must not be greater than the
range of IR rays.
 Power supply must be 9V D.C.
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IR Based Security Alarm

26. Applications
Night Vision Device IR Tracking
If not enough visible light available to see
unaided.
Convert ambient photons of light into
electrons and amplify them using a
chemical and electrical process before
finally converting them back into visible
light.
Infrared tracking, also known as infrared homing.
It is a missile guidance system which operates using
the IR E.M radiation emitted from a target to track
it.
These missile systems are often known as 'heat-
seekers' as infrared is radiated strongly by hot
bodies such as people, vehicles and aircraft.
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IR Based Security Alarm

27. THANKS
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