Automatic Door Sensor Light

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In this tutorial, we are making a project on an Automatic door sensor light circuit. The purpose of this circuit is to automatically activate the light of the room it is present in. it gets activated when someone enters the room and deactivates when they go outside. This circuit is using two ICs, one is a 555 timer IC that is used to provide oscillations in the circuit. The other IC is a CMOS decade counter IC, CD4017. It is used to provide low-range counting applications in a circuit.

Hardware Components

The following components are required to make Automatic Door Light Circuit

S.no	Component	Value	Qty
1.	Input supply DC	5-15V	1
2.	Reed switch	NC	1
3.	IC	NE555 Timer	1
4.	Decade Counter IC	CD4017	1
5.	Relay	–	1
6.	Diode	1N4001	1
7.	LED	–	2
8.	Transistor	2N4401	1
9.	Resistor	270KΩ, 220KΩ, 560KΩ, 10KΩ, 120RΩ, 390Ω, 100Ω	1
10.	Ceramic Capacitor	0.1µF, 10nF	1, 1
11.	Electrolytic Capacitor	100µF	1

NE555 IC Pinout

For a detailed description of pinout, dimension features, and specifications download the datasheet of 555 Timer

CD4017 Pinout

For a detailed description of pinout, dimension features, and specifications download the datasheet of CD4017

Automatic Door Light Circuit

Working Explanation

The operating voltage of this circuit is 5 to 15 volts DC. The circuit is working on the basis of an NC (normally closed) reed switch. A small permanent magnet is supposed to be fitted on the corner of the door in front of the reed switch which will be placed at the border of the door. So when the door opens the reed switch will go from normally close to normally open and sends an input signal to the circuit. The circuit will activate and both the ICs will start performing and turns on the relay switch attached to the output of the circuit. You can connect an AC lamp that you want to operate with this circuit. Make sure to use a relay having the same voltage as the operating voltage.