Security & Saftey

Electronic Eye Controlled Security System

We’ll see a simple Home Security application named Electronic Eye Controlled Security System in this project, which uses LDR as the main sensor and a few other components.


Security System with Electronic Eye Control Principle of a Circuit
Electronic Eye Controlled Security System Circuit Diagram

Components of a Circuit

Circuit Simulation Video for an Electronic Eye Controlled Security System

Circuit Design for an Electronic Eye Controlled Security System

Power Supply Circuit Design

Logic Circuit Design

What is the Electronic Eye Controlled Security System Circuit and How Does It Work?

Applications for Electronic Eye Controlled Security Systems


Magic eye is another name for electronic eye. Consider a doorbell that automatically rings when someone comes to your house, as automation is still a relatively new technology. This also adds protection to your home if someone tries to enter without your permission. An electronic eye is a simple electronic device that continuously monitors your home for visitors.

Electronic Eye Controlled Security System

The electronic eye circuit is presented in this project. Before diving into the intricacies of this circuit, familiarise yourself with the Light Activated Switch Circuit with LDR.

Electronic Eye Controlled Security System Circuit Principle

The circuit’s fundamental premise is to ring the doorbell whenever someone approaches the entrance. An LDR is utilised as the sensor in order to detect a human. The presence or absence of a person is determined by the light on the LDR. When there is an object at the door, the LDR goes dark, the buzzer goes off, and the LED begins to shine.

Circuit Diagram of Electronic Eye Controlled Security System

NOTE: Resistor R4 is 220Ω.

Circuit Components

  • 7805 Regulator
  • Resistors – 220Ω x 2, 1KΩ x 2, 100KΩ
  • 1N4007 PN Diode
  • Capacitors – 1µF, 10µF
  • Transistors – BC 547 x 2
  • Light Dependent Resistor (LDR)
  • Buzzer
  • LED
  • Bread board
  • Connecting wires
  • 9V battery

Electronic Eye Controlled Security System Circuit Simulation Video

Electronic Eye Controlled Security System Circuit Design

This circuit can be broken down into two halves. The power source is one, while the logic circuit is the other. A 9V supply from a battery is converted to 5V in the power supply circuit. When a shadow falls on the LDR, the logic circuit activates the buzzer and an LED.

Design of Power Supply Circuit

The battery, diode, regulator, and capacitors make up the power supply circuit. The diode is first powered by a 9V battery. The diode utilised here is a 1N4007 series P-N junction diode. The 1N4007 is linked in the forward bias condition in this circuit.

The diode’s primary function in this circuit is to safeguard the circuit against reverse polarity, or to protect the circuit if the battery is accidentally connected in the wrong polarity. As a result, the P-N junction diode coupled in forward bias allows current to flow only in one direction, protecting the circuit. Across the diode, there is a voltage drop. A 0.7V voltage is applied across the diode.

The output voltage of the circuit is regulated by a regulator. The 7805 is the regulator IC utilised here. The series is represented by 78, while the output voltage is represented by 05. As a result, the regulator’s output voltage is 5 volts. Before and after the regulator, two capacitors are utilised. The waves are eliminated by these two capacitors. As a result, a constant voltage is produced at the regulator’s output, which is then applied to the logic circuit.

Design of Logic Circuit

A Light Dependent Resistor, transistors, a buzzer, an LED, and a few passive components make up the logic circuit. In a voltage divider configuration, a 100K resistor is connected in series with the LDR. When a light-dependent resistor is placed in the dark, its resistance will be measured in mega ohms. When exposed to light, this resistance value will steadily drop. As a result, the resistances in the series vary.

When the LDR is turned off, it has a high resistance and outputs a logic high value. When the LDR is turned on, the resistance of the LDR lowers, resulting in a logic low voltage at the output.

The voltage divider’s output is sent to a transistor, which inverts the LDR’s input. The buzzer is driven by the second transistor. The diode is there as a safety precaution.

A 5V magnetic buzzer was used in this project. At the output, there are two pins. The supply is attached to one pin, and the Collector of the second Transistor is connected to the other pin. The LED is only used as a signal. The buzzer begins to ring when the output of the first transistor is high. The led is also switched on.

How to Operate the Electronic Eye Controlled Security System Circuit?

  • On a bread board, connect the circuit as shown in the circuit diagram.
  • Now, using a battery, connect the 9V supply voltage.
  • In the light, place the Light Dependent Resistor. The buzzer does not emit any sound, as you can see.
  • When the LDR is placed in the dark, the buzzer begins to sound. In addition, the buzzer’s LED will be switched on.
  • As the intensity of the light landing on the LDR grows, so does the sound made by the buzzer.

Electronic Eye Controlled Security System Applications

  • This is a component that can be utilised in doorbell circuits.
  • Garage door opener circuits can benefit from this.
  • Security applications can benefit from the usage of an electronic eye.


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