This document describes a project to automatically switch off lights when a person falls asleep. It uses an ATmega16 microcontroller, PIR sensor, and relay driver. The PIR sensor senses body movement and temperature and sends a signal to the microcontroller. If no movement is detected within the set time, the light will turn off to save electricity and effort. Otherwise, if movement is detected before the set time, the light will remain on. The goal is to reduce human effort by automating light switching based on presence detection.

1.  aSynopsisof
Automatic switching off of light when fell
asleep
A project
To be submitted by
Kumar Ankit
For the fulfilments of Bachelor of Technology
Department of Electronics and Communication Engineering
Gandhi Institute For Technology, Bhubaneswar

2. 1. Introduction
It is the human effort reducing devices.It makes switching off light when person fell asleep.It
consists of ATmega16 Microcontroller, PIR Sensor, Relay driver to accomplished the project
.It works on the basis of movement of the body as well as be temperature radiated by the body.
It will sense the movement of body and the temp radiated by the body by the PIR Sensor .When
the body is in inactive state until the set time in the microcontroller then it will send the digital
data ‘0’ to the microcontroller and hence the AC appliances (light) turns off. Similarly if some
movement is sensed by the PIR Sensor i.e when body is in active state then the Digital data
‘1’ is sent to the microcontroller and hence light is in glow state.
Here, PIR Sensor sense the human body movement as well as temperature radiated by the body
and send the signal to the ATmega 16 microcontroller, We use ATmega 16 microcontroller
here because this microcontroller equipped with internal oscillator for driving its clock .and
also it contains ADC interface as well as timer/counter and hence ATmega 16 receive the
digital data from the PIR Sensor and it work as there are some time is set to the
microcontroller and if no movement as well as radiated temp from body is sensed by the PIR
Sensor to the set time then light turns off and otherwise if any movement as well as temperature
radiated by the body is sensed my PIR Sensor before the set time then light is in glow state.
And Relay Drive is used as switching device. And hence by this project we save human effort
and also electricity.

3. 2. Feasibility
The main objective of this project is to by using the PIR Sensor the movement as well as
temperature radiated from the body is to be detected as well as when body is in inactive
state then it sensed by the PIR sensor and light goes off. so by which:-
. It saves electricity.
. It saves human effort.
. It relives the human eye.
Hence this will work until the set time in the microcontroller. When no movement of body
occur until the set time then the temperature radiated from the body is sensed by the PIR
sensor and light goes off, otherwise the light is in glow state.So, that we can say that it
varies from person to person.And it reduces the human effort.
By using this ATmega 16 microcontroller and PIR sensor, for upgrading we are using the LDR
which is light dependent resister. It automatically switching off light when sun rays falls on
it.where as at night time i.e at the absence of sun rays it automatically switched on the light.
But in the rainy and sunny season the on and off time will vary. But apart from all this it
reduces the energy consumption because of we are using the automatic switching on or off
light.

4. 3. Methodology/Planning of work

5. 4. Facilities Required
AVR Studios
. Microcontroller
. PIR Sensor
. Vero Band
. Microcontroller base
. LCD
. Variable resistor