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Home automation Final year project

Final year project

11/21/2011

ASIT DEVA

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Acknowledgment

Thanking you

Asit Krishna Deva

Dept of Applied Electronics & Instrumentation

Netaji Subhash Engineering College

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Contents

Objective

Project Details

Choosing the micro-controller and developing the ISP circuit/programming circuit for the same.Developing the logic.Developing the interfacing circuit for the sensors & the relays to control the final elements.Development of remote control unit.

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Objective

The project is aimed to design a home automation system for domestic purpose. The finished product will have the following features: -

The finished product will have 2 modes of operation – Automatic & Manual.Automatic mode of operation will make use of inputs from sensors to switch on/off electrical devices.Manual mode will allow the user to control the features at own will by using a remote control device.

The product will produce a smart home that will maximize the efficiency in use of resources and save the resource from being wasted.

The product is an attempt to introduce the advantages and comfort of an automated system at domestic level.

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Project details

The product will have these following basic features:-

Automatic modeThe systems will be able to sense the following parameters –

1. Presence of light;2. Temperature; &3. Presence of people.

Depending on the values of these sensors the system will control a light and a fan in a room.

Manual modeAll the sensors will be turned to just monitoring devices to monitor the parameters and the control will be left entirely on the user.The user will have a remote device which will give him/her the details of the parameter and buttons to control the light and fan.

The system will have a master switch will give the user an option to switch back to the traditional mode of controlling the lights and fans and bypass the whole automation system.

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Choosing the micro-controller and developing the ISP circuit/programming circuit for the same.

Micro-controller chosen: AVRReasons:

1)Easily available;2)ISP circuit easy to develop;3)In-built ADC which might be required to accept

inputs from the sensors;4)Popular all over the world, forums and groups

readily available for help; &5)IC has a very high tolerance; it doesn’t get

burned out to easily.

ISP Circuit Diagram.

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Developing the logic 1)Logic to sense the presence of light

An analog light sensor can be used through the ADC to produce the digital values corresponding to the amount of light it receives. This value can be used in simple if-else statement to control the light.

2)Logic to sense the temperature

An analog temperature sensor can be used through the ADC to produce the digital values corresponding to temperature it measures. This value can be used in simple if-else statement to control the fan.

3)Logic to sense the presence of people

2 IR sensors can be installed at the door way to keep a tab of people coming in or moving out of the room.

The figure shows the arrangement of 2 IR sensors. When a body obstructs the blue IR first and then the red IR then it will be considered that the person is moving into the room. While if the

obstructions happen the other way round the person shall be considered to move out of the room.A counter can be set to add 1 if a person moves into the room and subtract 1 if the person moves out of the room.

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All the controls of the light and fan matter only if the number of person in the room is 1 or more.

Developing the interfacing circuit for the sensors & the relays to control the final elements.

The interfacing circuits are one of the most important parts of the project.

1)Light sensors

Circuit diagram

2)Temperature sensors

Circuit diagram

3)IR sensors

Circuit diagram

The interfacing of the relays are important and should be done carefully to avoid hazards as the source will be an live AC source and the any simple mistake may lead to bigger accidents.A SPDT (Single Pole Double Throw) Relay is to be used.But to integrate it to the domestic circuits we must understand the arrangement of the domestic circuits being used today.

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Below is give the 2 circuit diagrams:1: The present domestic circuits.2: The planed circuit with relay.

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Development of remote control unit

Both the Controlling unit and the RC will have separate AVR controllers for processing.The controller in the RC will act as the slave and that in the Main controlling unit will be the master.A wireless protocol will be defining the mode of communication between the 2.The RC will have the following feature:

1. On/Off switch for light and fan.2. LCD display showing the parameters like

temperature, number of people.

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Interfacing the communication system with the AVR.

The mode of communication being RF, CC2500 is chosen as the device to be integrated in the system to provide it with the wireless communication protocol.

The chip is available in a certain module and that module

still need a break-out board to interface with the AVR. The complexity of the circuits is far beyond our reach so a readily available module will be purchased.

The final purchased board may look like this.