smart switches by arduino

1. 1
Chapter 1
Introduction
1.1 Aim of the Project:
This project is an implementation to the idea of touch based technology in the home
appliances.
The touch based technology is used in all over the world in now days so in the home appliances,
this technology is used for make our home to a smart home. Smart home consist the home
appliances like switch board and panel are with smart technology.
The general home appliances switch is made with direct connection of AC supply to the
switch so the danger of short circuit and shock of electricity. With the help of touch switch AC
supply is not directly given to the switch but the DC supply is given to the switch/ touch screen.
In touch switch the TFT touch shield is connected to the Arduino mega and the
programming is saved in the Arduino. The Arduino is works on the 5V DC supply so no chance
of shock in screen. The AC supply is given through the relay module and relay is operated
through Arduino.
1.2 Organization of Report
The chapter 2 gives detailed literature explanation regarding to Arduino mega 2560 and various
concepts of Arduino mega.
The chapter 3 deals with the TFT shield and give the idea about it.
The chapter 4 gives the idea about the relay module.
The chapter 5 gives the idea of advantages of this project.

2. 2
Chapter 2
Arduino Mega 2560
2.1 Introduction
The Arduino Mega 2560 is a microcontroller board based on the ATmega2560. It has 54
digital input/output pins (of which 14 can be used as PWM outputs), 16 analog inputs, 4 UARTs
(hardware serial ports), a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP
header, and a reset button. It contains everything needed to support the microcontroller; simply
connect it to a computer with a USB cable or power it with a AC to DC adapter or battery to get
started. The Mega is compatible with most shields designed for the Arduino Duemilanove or
Diecimila.
Arduino board designs use a variety of microprocessors and controllers. The boards are equipped
with sets of digital and analog input/output (I/O) pins that may be interfaced to various
expansion boards and other circuits. The boards feature serial communications interfaces,
including Universal Serial Bus (USB) on some models, which are also used for loading programs
from personal computers. The microcontrollers are typically programmed using a dialect of
features from the programming languages C and C++. In addition to using traditional compiler
tool chains, the Arduino project provides an integrated development environment (IDE) based on
the Processing language project.
The Arduino project started in 2003 as a program for students at the Interaction Design Institute
Ivrea in Ivrea, Italy, aiming to provide a low-cost and easy way for novices and professionals to
create devices that interact with their environment using sensors and actuators. Common
examples of such devices intended for beginner hobbyists include simple robots, thermostats,
and motion detectors.
The name Arduino comes from a bar in Ivrea, Italy, where some of the founders of the project
used to meet. The bar was named after Arduino of Ivrea, who was the margrave of the March of
Ivrea and King of Italy from 1002 to 1014

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Summary
Microcontroller ATmega2560
Operating Voltage 5V
Input Voltage (recommended) 7-12V
Input Voltage (limits) 6-20V
Digital I/O Pins 54 (of which 14 provide PWM output)
Analog Input Pins 16
DC Current per I/O Pin 40 mA
DC Current for 3.3V Pin 50 mA
Flash Memory 256 KB of which 8 KB used by boot loader
SRAM 8 KB
EEPROM 4 KB
Clock Speed 16 MHz
Power
The Arduino Mega can be powered via the USB connection or with an external power
supply. The power source is selected automatically. External (non-USB) power can come either
from an AC-to-DC adapter (wall-wart) or battery. The adapter can be connected by plugging a
2.1mm center-positive plug into the board's power jack. Leads from a battery can be inserted in
the Gnd and Vin pin headers of the POWER connector. The board can operate on an external
supply of 6 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than
five volts and the board may be unstable. If using more than 12V, the voltage regulator may

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overheat and damage the board. The recommended range is 7 to 12 volts. The Mega2560 differs
from all preceding boards in that it does not use the FTDI USB-to serial driver chip. Instead, it
features the Atmega8U2 programmed as a USB-to-serial converter. The power pins are as
follows:
 VIN
The input voltage to the Arduino board when it's using an external power source(as
opposed to 5 volts from the USB connection or other regulated power source). We can supply
voltage through this pin, or, if supplying voltage via the power jack, access it through this pin.
 5V
The regulated power supply used to power the microcontroller and other components on
the board. This can come either from VIN via an on-board regulator, or be supplied by USB or
another regulated 5V supply.
 3V3
A 3.3 volt supply generated by the on-board regulator. Maximum current draw is 50 mA.
 GND
Ground pins.
Memory
The ATmega2560 has 256 KB of flash memory for storing code (of which 8 KB is used
for the boot loader), 8 KB of SRAM and 4 KB of EEPROM (which can be read and written with
the EEPROM library).
Input and Output
Each of the 54 digital pins on the Mega can be used as an input or output, using
pinMode(), digitalWrite(), and digitalRead() functions. They operate at 5 volts. Each pin can
provide or receive a maximum of 40 mA and has an internal pull-up resistor (disconnected by
default) of 20-50 kꭥ.
In addition, some pins have specialized functions:
Serial: 0 (RX) and 1 (TX); Serial 1: 19 (RX) and 18 (TX); Serial 2: 17 (RX) and 16 (TX);
Serial 3: 15 (RX) and 14 (TX). Used to receive (RX) and transmit (TX) TTL serial data. Pins 0
and 1 are also connected to the corresponding pins of the ATmega8U2 USB-to-TTL Serial chip.
External Interrupts: 2 (interrupt 0), 3 (interrupt 1), 18 (interrupt 5), 19 (interrupt 4), 20
(interrupt 3), and 21 (interrupt 2). These pins can be configured to trigger an interrupt on a
low value, a rising or falling edge, or a change in value. See the attach Interrupt() function for
details.
PWM: 0 to 13. Provide 8-bit PWM output with the analogWrite() function.
SPI: 50 (MISO), 51 (MOSI), 52 (SCK), 53 (SS). These pins support SPI communication using
the SPI library. The SPI pins are also broken out on the ICSP header, which is physically
compatible with the Uno, Duemilanove and Diecimila.
LED: 13. There is a built-in LED connected to digital pin 13. When the pin is HIGH value, the
LED is on, when the pin is LOW, it's off.

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I2C: 20 (SDA) and 21 (SCL). Support I2C (TWI) communication using the Wire library
(documentation on the Wiring website). Note that these pins are not in the same location as the
I2C pins on the Duemilanove or Diecimila.
The Mega2560 has 16 analog inputs, each of which provide 10 bits of resolution (i.e. 1024
different values). By default they measure from ground to 5 volts, though is it possible to change
the upper end of their range using the AREF pin and analogReference() function.
There are a couple of other pins on the board:
AREF. Reference voltage for the analog inputs. Used with analogReference().
Reset. Bring this line LOW to reset the microcontroller. Typically used to add a reset button to
shields which block the one on the board.
Communication
The Arduino Mega2560 has a number of facilities for communicating with a computer,
another Arduino, or other microcontrollers. The ATmega2560 provides four hardware UARTs
for TTL (5V) serial communication. An ATmega8U2 on the board channels one of these over
USB and provides a virtual com port to software on the computer (Windows machines will need
a .inf file, but OSX and Linux machines will recognize the board as a COM port automatically.
The Arduino software includes a serial monitor which allows simple textual data to be sent to
and from the board. The RX and TX LEDs on the board will flash when data is being transmitted
via the ATmega8U2 chip and USB connection to the computer (but not for serial communication
on pins 0 and 1).
A Software Serial library allows for serial communication on any of the Mega2560's digital pins.
The ATmega2560 also supports I2C (TWI) and SPI communication. The Arduino software
includes a Wire library to simplify use of the I2C bus; see the documentation on the Wiring
website for details. For SPI communication, use the SPI library.
Programming
The Arduino Mega can be programmed with the Arduino software (download). For details, see
the reference and tutorials. The ATmega2560 on the Arduino Mega come pre burned with a boot
loader that allows us to upload new code to it without the use of an external hardware
programmer. It communicates using the original STK500 protocol (reference, C header files).
We can also bypass the boot loader and program the microcontroller through the ICSP (In
Circuit Serial Programming) header; see these instructions for details.
Automatic (Software) Reset
Rather then requiring a physical press of the reset button before an upload, the Arduino
Mega2560 is designed in a way that allows it to be reset by software running on a connected
computer. One of the hardware flow control lines (DTR) of the ATmega8U2 is connected to the
reset line of the ATmega2560 via a 100 nano farad capacitor. When this line is asserted (taken

6. 6
low), the reset line drops long enough to reset the chip. The Arduino software uses this capability
to allow you to upload code by simply pressing the upload button in the Arduino environment.
This means that the boot loader can have a shorter timeout, as the lowering of DTR can be well-
coordinated with the start of the upload.
This setup has other implications. When the Mega2560 is connected to either a computer running
Mac OS X or Linux, it resets each time a connection is made to it from software (via USB). For
the following half-second or so, the bootloader is running on the Mega2560. While it is
programmed to ignore malformed data (i.e. anything besides an upload of new code), it will
intercept the first few bytes of data sent to the board after a connection is opened. If a sketch
running on the board receives one-time configuration or other data when it first starts, make sure
that the software with which it communicates waits a second after opening the connection and
before sending this data.
The Mega2560 contains a trace that can be cut to disable the auto-reset. The pads on
either side of the trace can be soldered together to re-enable it. It's labeled "RESET-EN". You
may also be able to disable the auto-reset by connecting a 110 ohm resistor from 5V to the reset
line; see this forum thread for details.
USB Over current Protection
The Arduino Mega2560 has a resettable poly fuse that protects your computer's USB ports from
shorts and over current. Although most computers provide their own internal protection, the fuse
provides an extra layer of protection. If more than 500 mA is applied to the USB port, the fuse
will automatically break the connection until the short or overload is removed.
Physical Characteristics and Shield Compatibility
The maximum length and width of the Mega2560 PCB are 4 and 2.1 inches respectively,
with the USB connector and power jack extending beyond the former dimension. Three screw
holes allow the board to be attached to a surface or case. Note that the distance between digital
pins 7 and 8 is 160 mil (0.16"), not an even multiple of the 100 mil spacing of the other pins. The
Mega2560 is designed to be compatible with most shields designed for the Uno, Diecimila or
Duemilanove. Digital pins 0 to 13 (and the adjacent AREF and GND pins), analog inputs 0 to 5,
the power header, and ICSP header are all in equivalent locations.
Further the main UART (serial port) is located on the same pins (0 and 1), as are external
interrupts 0 and 1 (pins 2 and 3 respectively). SPI is available through the ICSP header on both
the Mega2560 and Duemilanove / Diecimila. Please note that I2C is not located on the same pins
on the Mega (20 and 21) as the Duemilanove / Diecimila (analog inputs 4 and 5).

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8. 8
2.2 Arduino Software (IDE)
The Arduino Integrated Development Environment - or Arduino Software (IDE) - contains a text
editor for writing code, a message area, a text console, a toolbar with buttons for common
functions and a series of menus. It connects to the Arduino and Genuino hardware to upload
programs and communicate with them.
Writing Sketches
Programs written using Arduino Software (IDE) are called sketches. These sketches are written
in the text editor and are saved with the file extension .ino. The editor has features for
cutting/pasting and for searching/replacing text. The message area gives feedback while saving
and exporting and also displays errors. The console displays text output by the Arduino Software
(IDE), including complete error messages and other information. The bottom right hand corner
of the window displays the configured board and serial port. The toolbar buttons allow you to
verify and upload programs, create, open, and save sketches, and open the serial monitor.
NB: Versions of the Arduino Software (IDE) prior to 1.0 saved sketches with the extension .pde.
It is possible to open these files with version 1.0, you will be prompted to save the sketch with
the .ino extension on save.
Verify
Checks your code for errors compiling it.
Upload
Compiles your code and uploads it to the configured board. See uploading below for
details.
Note: If you are using an external programmer with your board, you can hold down
the "shift" key on your computer when using this icon. The text will change to
"Upload using Programmer"
New
Creates a new sketch.
Open
Presents a menu of all the sketches in your sketchbook. Clicking one will open it
within the current window overwriting its content.
Note: due to a bug in Java, this menu doesn't scroll; if you need to open a sketch late in
the list, use the File | Sketchbook menu instead.

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Save
Saves your sketch.
Serial Monitor
Opens the serial monitor.
Additional commands are found within the five menus: File, Edit, Sketch, Tools, Help. The
menus are context sensitive, which means only those items relevant to the work currently being
carried out are available.
File
 New
Creates a new instance of the editor, with the bare minimum structure of a sketch already in
place.
 Open
Allows to load a sketch file browsing through the computer drives and folders.
 Open Recent
Provides a short list of the most recent sketches, ready to be opened.
 Sketchbook
Shows the current sketches within the sketchbook folder structure; clicking on any name opens
the corresponding sketch in a new editor instance.
 Examples
Any example provided by the Arduino Software (IDE) or library shows up in this menu item. All
the examples are structured in a tree that allows easy access by topic or library.
 Close
Closes the instance of the Arduino Software from which it is clicked.
 Save
Saves the sketch with the current name. If the file hasn't been named before, a name will be
provided in a "Save as.." window.
 Save as...
Allows to save the current sketch with a different name.
 Page Setup
It shows the Page Setup window for printing.
 Print
Sends the current sketch to the printer according to the settings defined in Page Setup.
 Preferences
Opens the Preferences window where some settings of the IDE may be customized, as the
language of the IDE interface.
 Quit
Closes all IDE windows. The same sketches open when Quit was chosen will be automatically
reopened the next time you start the IDE.

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Edit
 Undo/Redo
Goes back of one or more steps you did while editing; when you go back, you may go forward
with Redo.
 Cut
Removes the selected text from the editor and places it into the clipboard.
 Copy
Duplicates the selected text in the editor and places it into the clipboard.
 Copy for Forum
Copies the code of your sketch to the clipboard in a form suitable for posting to the forum,
complete with syntax coloring.
 Copy as HTML
Copies the code of your sketch to the clipboard as HTML, suitable for embedding in web pages.
 Paste
Puts the contents of the clipboard at the cursor position, in the editor.
 Select All
Selects and highlights the whole content of the editor.
 Comment/Uncomment
Puts or removes the // comment marker at the beginning of each selected line.
 Increase/Decrease Indent
Adds or subtracts a space at the beginning of each selected line, moving the text one space on the
right or eliminating a space at the beginning.
 Find
Opens the Find and Replace window where you can specify text to search inside the current
sketch according to several options.
 Find Next
Highlights the next occurrence - if any - of the string specified as the search item in the Find
window, relative to the cursor position.
 Find Previous
Highlights the previous occurrence - if any - of the string specified as the search item in the Find
window relative to the cursor position.
Sketch
 Verify/Compile
Checks your sketch for errors compiling it; it will report memory usage for code and variables in
the console area.
 Upload
Compiles and loads the binary file onto the configured board through the configured Port.
 Upload Using Programmer
This will overwrite the bootloader on the board; you will need to use Tools > Burn Bootloader to
restore it and be able to Upload to USB serial port again. However, it allows you to use the full
capacity of the Flash memory for your sketch. Please note that this command will NOT burn the
fuses. To do so a Tools -> Burn Bootloader command must be executed.

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 Export Compiled Binary
Saves a .hex file that may be kept as archive or sent to the board using other tools.
 Show Sketch Folder
Opens the current sketch folder.
 Include Library
Adds a library to your sketch by inserting #include statements at the start of your code. For more
details, see libraries below. Additionally, from this menu item you can access the Library
Manager and import new libraries from .zip files.
 Add File...
Adds a source file to the sketch (it will be copied from its current location). The new file appears
in a new tab in the sketch window. Files can be removed from the sketch using the tab menu
accessible clicking on the small triangle icon below the serial monitor one on the right side o the
toolbar.
Tools
 Auto Format
This formats your code nicely: i.e. indents it so that opening and closing curly braces line up, and
that the statements inside curly braces are indented more.
 Archive Sketch
Archives a copy of the current sketch in .zip format. The archive is placed in the same directory
as the sketch.
 Fix Encoding & Reload
Fixes possible discrepancies between the editor char map encoding and other operating systems
char maps.
 Serial Monitor
Opens the serial monitor window and initiates the exchange of data with any connected board on
the currently selected Port. This usually resets the board, if the board supports Reset over serial
port opening.
 Board
Select the board that you're using. See below for descriptions of the various boards.
 Port
This menu contains all the serial devices (real or virtual) on your machine. It should
automatically refresh every time you open the top-level tools menu.
 Programmer
For selecting a harware programmer when programming a board or chip and not using the
onboard USB-serial connection. Normally you won't need this, but if you're burning a boot
loader to a new microcontroller, you will use this.
 Burn Boot loader
The items in this menu allow you to burn a bootloader onto the microcontroller on an Arduino
board. This is not required for normal use of an Arduino or Genuino board but is useful if you
purchase a new ATmega microcontroller (which normally come without a bootloader). Ensure
that you've selected the correct board from the Boards menu before burning the bootloader on the
target board. This command also set the right fuses.

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Chapter 3
TFT Touch LCD shield
3.1 Introduction
A thin-film-transistor liquid-crystal display (TFT LCD) is a variant of a liquid-crystal
display (LCD) that uses thin-film transistor (TFT) technology to improve image qualities such as
addressability and contrast. A TFT LCD is an active-matrix LCD, in contrast to passive-
matrix LCDs or simple, direct-driven LCDs with a few segments.
TFT LCDs are used in appliances including television sets, computer monitors, mobile phones,
handheld video game systems, personal digital assistants, navigation systems and projectors.
TFT LCDs are also used in car instrument clusters because they allow the driver to customize the
cluster, as well as being able to provide a skeuomorphic, analog-like display
with digital elements.
A thin-film transistor (TFT) is a special kind of field-effect transistor made by depositing thin
films of an active semiconductor layer as well as the dielectric layer and metallic contacts over a
supporting (but non-conducting) substrate. A common substrate is glass, because the primary
application of TFTs is in liquid-crystal displays. This differs from the conventional transistor,
where the semiconductor material typically is the substrate, such as a silicon wafer.

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Arduino 2.4” Colored TFT Touch LCD Shield Description
Arduino 2.4" TFT LCD Touch shield is an Arduino UNO/ Mega compatible multicolored
TFT display with touch-screen and SD card socket. It is available in an Arduino shield
compatible pin out for attachment. The TFT driver is based on S6D112 with 8bit data and 4bit
control interface.
Features
• Compatible with 3.3/5V operation voltage level
• Compatible with UTFT library
• With SD Card Socket
Future Electronics Egypt Ltd. (Arduino Egypt).
Future Electronics Egypt Ltd. (Arduino Egypt).
The Arduino 2.4“E TFT Touch shield uses the S6D1121 controller, it support 8bit data interface.
The touch IC is TSC2046.

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3.2 Pin diagram of TFT shield

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Operation voltage level setting switch
When using the Arduino 2.4”E TFT Touch shield with 5V operation level development board –
like the Arduino UNO, Arduino MEGA and so on, set the operation voltage level switch to 5V
side. When using the Arduino 2.4“E TFT Touch shield with 3.3V operation level development
board – like the Iteaduino BT, leaf maple, chipKit UNO and so on, set the operation voltage level
switch to 3.3V side.
3.3 Construction
diagram of the pixel layout

16. 16
The liquid crystal displays used in calculators and other devices with similarly simple
displays have direct-driven image elements, and therefore a voltage can be easily applied across
just one segment of these types of displays without interfering with the other segments. This
would be impractical for a large display, because it would have a large number of (color) picture
elements (pixels), and thus it would require millions of connections, both top and bottom for
each one of the three colors (red, green and blue) of every pixel. To avoid this issue, the pixels
are addressed in rows and columns, reducing the connection count from millions down to
thousands. The column and row wires attach to transistor switches, one for each pixel. The one-
way current passing characteristic of the transistor prevents the charge that is being applied to
each pixel from being drained between refreshes to a display's image. Each pixel is a
small capacitor with a layer of insulating liquid crystal sandwiched between transparent
conductive ITO layers.
The circuit layout process of a TFT-LCD is very similar to that of semiconductor products.
However, rather than fabricating the transistors from silicon, that is formed into a crystalline
silicon wafer, they are made from a thin film of amorphous silicon that is deposited on a glass
panel. The silicon layer for TFT-LCDs is typically deposited using
the PECVD process. Transistors take up only a small fraction of the area of each pixel and the
rest of the silicon film is etched away to allow light to easily pass through it.
Polycrystalline silicon is sometimes used in displays requiring higher TFT performance.
Examples include small high-resolution displays such as those found in projectors or
viewfinders. Amorphous silicon-based TFTs are by far the most common, due to their lower
production cost, whereas polycrystalline silicon TFTs are more costly and much more difficult to
produce.
TFTs can be made using a wide variety of semiconductor materials. A common material
is silicon. The characteristics of a silicon-based TFT depend on the silicon's crystalline state; that
is, the semiconductor layer can be either amorphous silicon,[1] microcrystalline silicon, or it can
be annealed into poly silicon.
Other materials which have been used as semiconductors in TFTs include compound
semiconductors such as cadmium selenide, or metal oxides such as zinc oxideor hafnium
oxide. An application for hafnium oxide is as a high-κ dielectric. TFTs have also been made
using organic materials, referred to as organic field-effect transistors OTFTs.
By using transparent semiconductors and transparent electrodes, such as indium tin oxide (ITO),
some TFT devices can be made completely transparent. Such transparent TFTs (TTFTs) can be
used for construction of video display panels. Because conventional substrates cannot withstand
high annealing temperatures, the deposition process must be completed under relatively low
temperatures. Chemical vapor deposition and physical vapor deposition (usually sputtering) are
applied. The first solution-processed TTFTs, based on zinc oxide, were reported in 2003 by
researchers at Oregon State University.[4] The Portuguese laboratory CENIMAT at

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the Universidade Nova de Lisboa has produced the world’s first completely transparent TFT at
room temperature. CENIMAT also developed the first paper transistor, which may lead to
applications such as magazines and journal pages with moving images.
3.4 Applications
The best known application of thin-film transistors is in TFT LCDs, an implementation
of LCD technology. Transistors are embedded within the panel itself, reducing cross talk
between pixels and improving image stability.
As of 2008, many color LCD TVs and monitors use this technology. TFT panels are frequently
used in digital radiography applications in general radiography. A TFT is used in both direct and
indirect capture as a base for the image receptor in medical radiography.
AMOLED (active-matrix organic light-emitting diode) screens also contain a TFT layer.
The most beneficial aspect of TFT technology is its use of a separate transistor for each pixel on
the display. Because each transistor is small, the amount of charge needed to control it is also
small. This allows for very fast re-drawing of the display.

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Chapter 4
Relay Module
4.1 Introduction
Arduino Relay Shield employs high quality relay with eight channels input and eight channels output.
It can be connected to 250V/10A AC element or 24V/10A DC element to the maximum, therefore, it can be
used to control lights, motors and etc.
The modularized design makes it easy to connect to Arduino expansion board. The output state of the relay is
shown by a luminous diode for the convenience of actual application.
Specification
Control signal: TTL voltage
Rated load:
10A 250VAC
10A 125VAC
10A 30DC
10A 28VDC
Rated Through-current: 10A(NO) 5A(NC)
Max Switching Voltage: 250VAC 30VDC
Contact actuation time: ﹤10ms
Definition of module pins:
Pin 1 -Pin 8----Controlling end
Overview
This is a 5V 8-Channels Relay module, It can be controlled directly by a wide range of
microcontrollers such as Arduino, AVR, PIC, ARM and MSP430. 8 relays are included in this
module, with “NC” ports means “Normally connected to COM” and “NO” ports means
“Normally open to COM”. This module also equipped with 8 LEDS to show the status of relays.
Features
8 mechanical relays with status indicator LED
Both “NC” and “NO” ports for each relay

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Relay switch:

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Chapter 5
Auxiliary Component and Advantage of Project
Auxiliary Component
1. Bulbs
2. Bulb holders
3. Male-female wire
4. Arduino USB cable
5. Circuit board
6. Adaptor for DC supply
Advantages
 The switch is free from danger of electric shock.
 The switch can be made according to our requirement and can expand in future.
 It is free from mechanical error like block the switch due to any reason.

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References
http://www.arduino.org
http://www.tftshield.com
https://www.arduinomega2560.org
http://www.arduinobegning.in
http://www.homeautomation.com