automatic room temperature control

CONTENTS

• Problem statement

• Introduction

• Methodology

• Circuit Diagram

• Components

• Applications

• Conclusion

• References

Problem statement

• Todays world is affected by a phenomenon of global warming due to which the temperature is rising which makes the human lives uneasy.

• Thus, there is a prevalent use of a Air Conditioners in homes thus there is a huge requirement of power.

• In this project work, we are going to control the temperature of multiple rooms using Air-Conditioners by sharing the temperature among them. This will also save electric power.

Introduction

• In this project work the temperature of the two rooms are controlled using air conditioner .But due to the power shortage low voltage vary often we are not able to start both the air conditioner simultaneously .In such cases our project is aimed at starting one ac among both depending upon the temperature value at a particular room .

• If the temperature on the particular room is above certain range then the AC in that room will start up and during this time the AC in the other room will remain switched off.

• When the temperature goes below 25 degree in the room where AC is already on will be switched off automatically.

• Then if the temperature on the other room during the time is above 30 degree then the AC in that room will start up and vice versa .

• The second feature of our project is aimed at switching of the AC automatically when there is absence of human beings in a particular room .

• The entire scheme is designed using number of ATMEGA16 PU microcontrollers , temperature sensors , digital counter , Relay etc.

Methodology

• 1. When no people are present in both the rooms then both room AC will remain switch off.

• 2. When the people enter in the room1 and if its temperature(T1) > 30 degree then AC1 will be switched on, while AC2 will remain off.AC1 will continue to run till the temperature of the room becomes 25 degree.

• 3. When the people enter in the room2 and if its temperature(T2) > 30 degree then AC2 will be switched on, while AC1 will remain off.AC2 will continue to run till the temperature of the room becomes 25 degree.

T1=TEMPERATURE OF ROOM 1

• T2=TEMPERATURE OF ROOM 2

COMPONENTS

• MICROCONTROLLER (ATMEGA 16)

• POWER SUPPLY UNIT

• RELAY DRIVER CIRCUIT

• FAN

• TEMPERATURE SENSOR

• IR Tx and IR Rx

• LCD

• SOFTWARE REQUIREMENTS

CIRCUIT DIAGRAM

Power Supply Unit

1000uF

50Hz

3

IC7812

GND

12-0-12

+12VDC

LED

+5VDC

LED

230VAC1

2

31

2

- +

IN4007

IC7805

POWER SUPPLY SECTION

POWER SUPPLY SECTION

basically consisting of three sections as follows

• Step down section

• Rectifier Section

• Regulator section

Relay Driver Circuit• A relay is an electrically

operated switch. Electric current through the coil of the relay creates a magnetic field which attracts a lever and changes the switch contacts.

• The coil current can be on or off so relays have two switch positions and they are double-throw (changeover) switches.

Temperature Sensor(LM35)

Working Principle-• It has linear relationship

between output voltage & Celsius temperature scale.

• It gives an output voltage that is Proportional to the Celsius temperature.

• Scale factor is 10mv/ degree C.

IR Transmitter & Receiver

• IR LED is used as a source of infrared rays. It comes in two packages 3mm or 5mm. 3mm is better as it is requires less space.

• IR sensor is nothing but a photodiode, which is sensitive for infrared radiation.

• This infrared transmitter and receiver is called as IR TX-RX pair.

Software Requirements

• AVR STUDIO 4

• LANGUAGES EMBEDDED C

Why Embedded C ?

• It is easier and less time consuming to write in C than Assembly.

• C is easier to modify and update.

• We can use code available in function libraries.

• C code is portable to other micro controller with little of no modification.

• Compilers produce hex files that is downloaded to ROM of microcontroller.

• C programming is less time consuming, but has larger hex file size.

Applications

• Industrial Automation.

•Home Automation.

• Electric power can be saved using this project.

Conclusion

• This project will solve the day-to-day problem where AC’s do not start up due to low voltage , generally in rural areas .

• This will start the AC depending upon the temperature label in a room by sharing the load .

• Also this project can be extended for controlling the temperature in more rooms in an apartment in future..

References

1. “Industrial instrumentation” by S.K Singh.

2. “Measurement and instrumentation and its applications” by E.D doublin .

3. “Measurement and instrumentation” by A.K sahani.

4. http://www.atmel.com

5. http://www.alldatasheet.com

6. C.Sujana,A.P.Ramesh,P.G reddy, “Automatic detection of human and Energy saving based on Zigbee Communication”,International Journal on Computer Science and Engineering (IJCSE) ISSN : 0975-3397, Vol. 3 No. 6 June 2011