Do you often forget to turn off the lights when you leave your room?

If yes, then this device is just the thing for you to create and start saving energy.

Here is the youtube link of the device in action:

https://youtu.be/bIMr5IV9O_Y

Step 1: GATHER THE MATERIALS

This device makes use of :

1) 2 X Infrared Sensor

2) Arduino UNO Board

3) Breadboard

4) a Relay Module

5) 3 LEDs

6) a DC motor and a propeller (to represent a fan)

7) 3 X 1k resistors

8) Breadboard Power Supply (to provide power for motor)

Step 2: HOW THE DEVICE WORKS??

Urjaa( URJAA is the Hindi word for energy) is a device which makes use of two infrared sensors to detect whether a person is entering inside the room or exiting from the room. One infrared sensor is placed before the other in the entrance and are placed at different heights. The order in which the sensors are triggered helps the Arduino to recognize whether a person has entered or left the room. If the first infrared is triggered and then the second infrared sensor is triggered simultaneously, then it will mean that a person has entered inside the room and if the second infrared is triggered first and then the first infrared is triggered then it will mean that a person has left the room.

Whenever the sensors are triggered, a variable in the arduino code named person is increased or decreased by one depending on the order in which the sensors are triggered. The arduino does not switch off the appliances until the value of the variable becomes 0.

Step 3: WIRE UP THE ELECTRONICS!!

Both the infrared sensors are powered from the 5v pin of the arduino.

5v of Arduino---->Vcc of both sensors

GND of Arduino-----> GND of both sensors

pin 8 of Arduino----> OUT of infrared 1

pin 7 of Arduino----> OUT of infrared 2

The positive terminal of LEDs are connected to pins 2, 3, 4 of arduino with a 1k resistor and the negative terminal is connected to ground.

Vcc of Relay module-----> 5v pin of Arduino

GND of Relay module-----> GND of Arduino

IN2 pin of Rekay Module-----> pin 12 of Arduino

5v pin of the Breadboard Power Supply is connected to COM on relay and the GND pin is connected to the motor and the other terminal of motor is connected to NO(Normally Open) on the Relay.

NOTE: The Breadboard Power Supply is used to provide power to the motor and relay is used for switching a purpose. A NPN transistor can be used in place of the relay as switch. But the relay module will be required to implement the device at the home.

NOTE: Carefully set the range of the infrared sensors using the potentionometer and place sensors at different heights to prevent them from interfering in each other's path and to allow the creation of a time gap between the triggering of each sensor.