SMART AGRICULTURE ROBOT FOR

SEEDING AND PLOUGHING

Abstract:

The Smart Agriculture Robot for for Seeding and ploughing is an

autonomous system designed to assist with essential farming tasks such as grass
cutting, seed sowing, and irrigation. It is powered by an Arduino Mega 2560
microcontroller, which coordinates various sensors and actuators for efficient
operation. The robot uses a Bluetooth module for wireless remote control, enhancing
ease of use and mobility.

Four DC motors with wheels provide movement across agricultural

terrain, while an ultrasonic sensor enables obstacle detection and navigation. A seed
sowing mechanism with a funnel ensures accurate and uniform seed distribution.
The robot includes a relay module to manage different electrical components
effectively.

All components are securely housed in a plastic box for protection

against environmental factors. It operates using a 12V battery and an integrated
power supply system for reliable energy management. The mechanical design
ensures functionality and durability in field conditions.

This robot offers a cost-effective, flexible solution for small-scale

farmers. By automating repetitive tasks, it reduces manual labor and increases
productivity. The system contributes to smarter and more sustainable agricultural
practices, making it a valuable tool for modern farming.
Introduction:

Agriculture stands as the linchpin of rural India, yet farmers

encounter challenges such as a shortage of timely and efficient workforce due to
significant rural-to-urban migration. To alleviate the burdens faced by farmers, there
arises a pressing need for the automation of farming practices. The primary
motivation behind automating these processes lies in the intent to save time and
energy traditionally required for repetitive farming tasks, coupled with the aspiration
to enhance yield productivity through precision farming techniques. The proposed
solution involves the integration of a robotic system capable of autonomously
seeding, watering, and applying pesticides. By embracing automation, the farming
sector seeks to not only mitigate the challenges posed by labor shortages but also to
usher in a new era of efficiency and precision, ensuring a sustainable and
technologically advanced future for Indian agriculture

The Smart Agriculture Robot assists with farming tasks like grass
cutting, seed sowing, and irrigation. Powered by an Arduino Mega 2560, it uses
sensors, actuators, and a Bluetooth module for remote control. Four DC motors drive
movement, and an ultrasonic sensor aids navigation. A seed sowing mechanism
ensures uniform distribution.

It operates on a 12V battery with a reliable power system. The robot’s

components are housed in a protective plastic box for durability. This system offers
a cost-effective solution, automating tasks and increasing productivity. It helps
small-scale farmers with sustainable, efficient agriculture.
Embedded system implementation
Introduction:
An embedded system is one kind of a computer system mainly
designed to perform several tasks like to access, process, and store and also control
the data in various electronics-based systems. Embedded systems are a combination
of hardware and software where software is usually known as firmware that is
embedded into the hardware. One of its most important characteristics of these
systems is, it gives the o/p within the time limits. Embedded systems support to make
the work more perfect and convenient. So, we frequently use embedded systems in
simple and complex devices too. The applications of embedded systems mainly
involve in our real life for several devices like microwave, calculators, TV remote
control, home security and neighborhood traffic control systems, etc.

User interface

Embedded system

Software Hardware
Inputs Output

Link to other systems

Fig: Overview of embedded system

Embedded system:
Embedded system includes mainly two sections, they are

1. Hardware
2. Software

Input devices interfacing

and driver circuits

Timers Memory

Power
Application
supply and
Processor Serial specific
oscillator
communication circuits
circuits
ports

Interrupt Parallel
controller ports

Output devices interfacing

Block diagram of embedded system
Embedded System Hardware:

As with any electronic system, an embedded system requires a hardware

platform on which it performs the operation. Embedded system hardware is built
with a microprocessor or microcontroller. The embedded system hardware has
elements like input output (I/O) interfaces, user interface, memory and the display.
Usually, an embedded system consists of:

• Power Supply
• Processor
• Memory
• Timers
• Serial communication ports
• Output/Output circuits
• System application specific circuits

Embedded systems use different processors for its desired operation. Some of the
processors used are

1. Microprocessor

2. Microcontroller

3. Digital signal processor

Microprocessor vs Microcontroller

Microprocessor

• CPU on a chip.
• We can attach required amount of ROM, RAM and I/O ports.
• Expensive due to external peripherals.
• Large in size
• general-purpose

Microcontroller

• Computer on a chip
• fixed amount of on-chip ROM, RAM, I/O ports
• Low cost.
• Compact in size.
• Specific –purpose

Embedded System Software:

The embedded system software is written to perform a specific function.

It is typically written in a high level format and then compiled down to provide code
that can be lodged within a non-volatile memory within the hardware. An embedded
system software is designed to keep in view of the three limits:

• Availability of system memory

• Availability of processor’s speed
• When the system runs continuously, there is a need to limit power
dissipation for events like stop, run and wake up.
Bringing software and hardware together for embedded system:

To make software to work with embedded systems we need to bring

software and hardware together. for this purpose we need to burn our source code
into microprocessor or microcontroller which is a hardware component and which
takes care of all operations to be done by embedded system according to our code.

Generally we write source codes for embedded systems in assembly

language, but the processors run only executable files. The process of converting
the source code representation of your embedded software into an executable
binary image involves three distinct steps:

1) Each of the source files must be compiled or assembled into an object file.
2) All of the object files that result from the first step must be linked together to
produce a single object file, called the re-locatable program.
3) Physical memory addresses must be assigned to the relative offsets within the
re-locatable program in a process called relocation.
The result of the final step is a file containing an executable binary image that is
ready to run on the embedded system.

Source code

Assembler

Linker

Locator

Executable file

Processor

Flow of burning source code to processor

Applications:

Embedded systems have different applications. A few select applications of

embedded systems are smart cards, telecommunications, satellites, missiles, digital
consumer electronics, computer networking, etc
Embedded Systems in Automobiles

• Motor Control System

• Engine or Body Safety
• Robotics in Assembly Line
• Mobile and E-Com Access

Embedded systems in Telecommunications

• Mobile computing
• Networking
• Wireless Communications

Embedded Systems in Smart Cards

• Banking
• Telephone
• Security Systems
Implementation flow:

Stage 1:
Considering the problems of existing methods and giving solution to that problem
by considering the basic requirements for our proposed system

Stage 2:

Considering the hardware requirement for the proposed system

For this we need to select the below components:

1. Microcontroller

2. Inputs for the proposed system (ex: sensors, drivers etc..,)

3. Outputs (ex: relays, loads)

Stage 3:

After considering hardware requirements, now we need to check out the

software requirements. Based on the microcontroller we select there exists
different software for coding, compiling, debugging. we need to write source code
for that proposed system based on our requirements and compile, debug the code
in that software .

After completing all the requirements of software and hardware we need to

bring both together to work our system. For this we need to burn our source code
into microcontroller, after burning our source code to microcontroller then connect
all input and output modules as per our requirement.
Literature review

[1] Agricultural Robot for Automatic Ploughing and Seeding

2015 IEEE International Conference on Technological Innovations in ICT

(TIAR 2015) (Amrita Sneha.A, Abirami.E, Ankita.A, Mrs. R. Praveen, Mrs. R.
Srimeena).

This paper explains on building a robot equipped for performing tasks

like sowing, seed apartioning. It likewise gives manual control when required and
watches the moisturity with the assistance of dampness sensors .The fundamental
segment here is the AVR At mega microcontroller that regulates the whole cycle. At
first the robot works the whole field and continues to sowing, all the while
apartioning seeds next to each other. On the field the robot works in an automated
mode, however outside the field is carefully worked in manual mode.

[2] “Design and Implementation of Seeding Agricultural Robot” (JIRAS)

(P.Usha, V. Maheswari, Dr. V. Nandagopal)

This paper describes how can a robot be utilized to build up the way
toward developing farming area without the utilization of labor. The point of the
paper is to reduce the labor, time and increment the profitability rate.

[3]. Automated Farming Using Microcontroller and Sensors (IJSRMS) ISSN:

23493371 (Abdullah Tanveer, Abhishek Choudhary, Divya Pal, Rajani Gupta,
Farooq Husain) Farming should be possible utilizing new innovations to yield
higher development of the harvests.
 In this task, we will check temperature, light, moistness and soil dampness
in the field zone. The paper here portrays about programmed control highlights with
most recent hardware innovation utilizing microcontroller and GSM telephone line.
The venture works consequently and henceforth diminishes the labor.

[4] IOT Based Smart Agriculture IJARCCE June 2016 (Nikesh Gondchawar1,
Prof. Dr. R. S. Kawitkar2)

In this paper an undertaking model for horticulture robot is depicted

about the fresher situation of diminishing water tables, evaporating of streams and
tanks, flighty climate present a critical need of appropriate use of water.

[5] Sachin .D.Khirade, A.B.patil,” Plant disease detection Using image

processing,”2015, International conference on computing communication
control and automation, IEEE.

The identification of a plant sickness is the way to forestall the misfortunes

in the yield and amount of the horticultural item. The investigations of the plant
infections works dependent on outwardly detectable examples seen on the plant.
Wellbeing observing and illness identification of a plant is extremely basic for
maintainable farming. It is frequently very hard to screen the plant sicknesses
physically. It requires an enormous measure of work, expertize in the plant illnesses,
and furthermore require the exorbitant preparing time to dissect. Henceforth, picture
preparing is a procedure that is utilized for the discovery of plant sicknesses. Illness
recognition measure includes the means like picture procurement, picture pre-
handling, picture division, highlight extraction and order. This paper examined about
the strategies utilized for the discovery of plant illnesses utilizing their leaves
pictures. This paper likewise depicted about some division and highlight extraction
calculation utilized in the plant infection identification.
[6] Vijai singh, Varsha, A.K.Mishra,Detection of unhealthy region of plant
leaves using image processing and genetic algorithm, 205, ICA CEA, India.
The economy of a nation relies upon the profitability from agribusiness.
The distinguishing proof of a plant infection is the fundamental key for forestalling
the misfortunes in the efficiency and furthermore for improving the nature of a rural
item i.e., food. Conventional techniques are dependable however it requires a human
asset for outwardly noticing the plant leaf designs and analyze the illness dependent
on their insight. Conventional technique burns-through additional time, dull work
for works. In enormous ranch lands, beginning phase identification of plant illness
by utilizing computerized procedures will diminish the misfortune in efficiency and
furthermore improvement in the result. In this paper, we propose a dream based
programmed recognition of plant illness location utilizing Image Processing
calculation. The picture preparing calculation is created to recognize the plant
contamination or illness by distinguishing the shading highlight of the leaf region.
K mean calculation is utilized for shading division and GLCM is utilized for
sicknesses order. Vision based plant disease indicated productive outcome and
promising execution.

[7] Monica Jhuria, Ashwani kumar and Rushikesh Borse, Image processing for
Smart farming, detection of Disease and Fruit Grading, continuing of the 2013,
IEEE, second global meeting on picture Information processing.
Because of the expanding request in the farming business, the need to
satisfactorily grow a plant and extension in its effectiveness is huge. To do thusly, it
is basic to screen the plant during its create period, just as, at the hour of reap which
set aside a long effort to break down. In this paper picture handling is utilized as an
instrument to screen the illnesses on organic products during cultivating, directly
from ranch to gathering dependent on the caught picture. For this reason counterfeit
neural organization idea is utilized. Back engendering idea is utilized for weight
change of preparing information base. The pictures are ordered and planned to their
particular sickness classifications on premise of three component vectors, to be
specific, shading, surface and morphology. From these element vectors morphology
gives 90% right outcome and it is more than other two element vectors. This paper
exhibits compelling calculations for spread of illness and mango tallying. Handy
usage of neural organizations which helps in dissecting the infection which has been
finished utilizing MATLAB programming.

[8] Mrunalani .R.Badnakhe,Prashant Infected leaf analysis and comparison by

otsu threshold and K means clustering, International journal of advanced
research in computer science and software engineering,volu me2,Issue 3,march
2012.

The paper by Mrunalani R. Badnakhe and Prashant focuses on analyzing

infected plant leaves using image processing techniques. It compares Otsu
thresholding, which segments images based on pixel intensity, with K-means
clustering, a method that groups similar pixels into clusters. Both techniques are
applied to identify infected regions on the leaf. The study aims to determine which
method performs better for infection detection. Published in the Journal of Advanced
Research in Computer Science and Software Engineering in 2012, the paper
contributes to automated plant disease detection.
Existing method

Traditional farming methods often rely heavily on manual labor, making

tasks such as grass cutting, seed sowing, and irrigation time-consuming and labor-
intensive. In some cases, agricultural robots have been developed to automate these
processes, but many of them lack versatility and are designed to perform only a
single function. For example, some robots focus on irrigation or grass cutting
alone, and they may not include advanced environmental sensors, making them
less adaptable to varying conditions. Additionally, many existing systems are
costly, complex to operate, or limited by battery life, reducing their overall
efficiency for small-scale agricultural operations.

Proposed method

The proposed "Multipurpose Agriculture Robot" integrates multiple

functions such as, seed sowing, and irrigation into a single, cost-effective system.
Powered by an Arduino Mega 2560, this robot uses sensors to monitor the
environment, including temperature,. It features, a seed sowing funnel. Equipped
with an ultrasonic sensor for obstacle detection and a Bluetooth module for remote
control, the robot can autonomously perform tasks while adapting to changing
environmental conditions. This versatility and integration of various functionalities
allow the robot to efficiently assist in small-scale agricultural tasks, making it a
highly adaptable and practical solution.
Block diagram:

Solar Panel Power supply

Bluetooth
Module
Servo

Relay 1 DC Motor
Arduino
Mega 2560

Ultrasonic Relay 2 Dc Motor

Sensor
Hardware components:
• Arduino Mega 2560
• LCD
• Bluetooth Module
• DC Motors
• Wheels
• Dummy Shafts
• Motor Driver
• Ultrasonic Sensor
• Relay
• Funnel

Software components:
• Embedded C
• Arduino IDE
Description:
Arduino Mega:

What is Arduino Mega?

The Arduino Mega 2560 is a microcontroller board based on the ATmega2560
(datasheet). 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.
Programming
The Mega 2560 board can be programmed with the Arduino Software (IDE). For
details, see the reference and tutorials.

The ATmega2560 on the Mega 2560 comes preprogrammed with a bootloader that
allows you 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).

You can also bypass the bootloader and program the microcontroller through the
ICSP (In-Circuit Serial Programming) header using Arduino ISP or similar; see
these instructions for details.

The ATmega16U2 (or 8U2 in the rev1 and rev2 boards) firmware source code is
available in the Arduino repository. The ATmega16U2/8U2 is loaded with a DFU
bootloader, which can be activated by:

On Rev1 boards: connecting the solder jumper on the back of the board (near the
map of Italy) and then resetting the 8U2.

On Rev2 or later boards: there is a resistor that pulling the 8U2/16U2 HWB line to
ground, making it easier to put into DFU mode. You can then use Atmel's FLIP
software (Windows) or the DFU programmer (Mac OS X and Linux) to load a new
firmware. Or you can use the ISP header with an external programmer (overwriting
the DFU bootloader). See this user-contributed tutorial for more information.
Warnings:
The Mega 2560 has a resettable polyfuse that protects your computer's
USB ports from shorts and overcurrent. 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.

Power

The Mega 2560 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 become unstable. If using more than 12V, the voltage regulator may overheat
and damage the board. The recommended range is 7 to 12 volts.
 The power pins are as follows:

• VIN. The input voltage to the board when it's using an external power source (as
opposed to 5 volts from the USB connection or other regulated power source). You
can supply voltage through this pin, or, if supplying voltage via the power jack,
access it through this pin.
• 5V. this pin outputs a regulated 5V from the regulator on the board. The board can
be supplied with power either from the DC power jack (7 - 12V), the USB connector
(5V), or the VIN pin of the board (7-12V). Supplying voltage via the 5V or 3.3V
pins bypasses the regulator, and can damage your board. We don't advise it.
• 3V3. A 3.3 volt supply generated by the on-board regulator. Maximum current draw
is 50 mA.
• GND. Ground pins.
• IOREF. This pin on the board provides the voltage reference with which the
microcontroller operates. A properly configured shield can read the IOREF pin
voltage and select the appropriate power source or enable voltage translators on the
outputs for working with the 5V or 3.3V.

Memory

The ATmega2560 has 256 KB of flash memory for storing code

(of which 8 KB is used for the bootloader), 8 KB of SRAM and 4 KB of EEPROM
(which can be read and written with the EEPROM library).
Input and Output
See the mapping between Arduino pins and Atmega2560 ports:

ATmega2560-Arduino Pin Mapping

Below is the pin mapping for the Atmega2560. The chip used in Arduino 2560.
There are pin mappings to Atmega8 and Atmega 168/328 as well.

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 20 mA as recommended operating condition
 and has an internal pull-up resistor (disconnected by default) of 20-50 k ohm. A
maximum of 40mA is the value that must not be exceeded to avoid permanent
damage to the microcontroller.

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
ATmega16U2 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 level, a rising or falling edge, or a change in level. See
the attachInterrupt() function for details.
• PWM: 2 to 13 and 44 to 46. 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 Arduino /Genuino Uno and the old
Duemilanove and Diecimila Arduino boards.
• 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.
• TWI: 20 (SDA) and 21 (SCL). Support TWI communication using the Wire library.
Note that these pins are not in the same location as the TWI pins on the old
Duemilanove or Diecimila Arduino boards.
 See also the mapping Arduino Mega 2560 PIN diagram.

The Mega 2560 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 analog
Reference() 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 Mega 2560 board has a number of facilities for communicating with a computer,
another board, or other microcontrollers. The ATmega2560 provides four hardware
UARTs for TTL (5V) serial communication. An ATmega16U2 (ATmega 8U2 on
the revision 1 and revision 2 boards) 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 (IDE) 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/ATmega16U2 chip and USB connection to the computer (but not for
serial communication on pins 0 and 1).
A SoftwareSerial library allows for serial communication on any of the Mega 2560's
digital pins.

The Mega 2560 also supports TWI and SPI communication. The Arduino
Software (IDE) includes a Wire library to simplify use of the TWI bus; see
the documentation for details. For SPI communication, use the SPI library.

Physical Characteristics and Shield Compatibility

The maximum length and width of the Mega 2560 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 Mega 2560 is designed to be compatible with most shields designed for the Uno
and the older Diecimila or Duemilanove Arduino boards. 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. Furthermore, 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 Mega 2560 and
Duemilanove / Diecimila boards. Please note that I2C is not located on the same pins
on the Mega 2560 board (20 and 21) as the Duemilanove / Diecimila boards (analog
inputs 4 and 5).
Automatic (Software) Reset

Rather than requiring a physical press of the reset button before an upload,
the Mega 2560 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 nanofarad
capacitor. When this line is asserted (taken low), the reset line drops long enough to
reset the chip. The Arduino Software (IDE) uses this capability to allow you to
upload code by simply pressing the upload button in the Arduino environment. This
means that the bootloader 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 Mega 2560 board 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 ATMega2560. 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 Mega 2560 board 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.
Revisions
The Mega 2560 does not use the FTDI USB-to-serial driver chip used in
past designs. Instead, it features the ATmega16U2 (ATmega8U2 in the revision 1
and revision 2 Arduino boards) programmed as a USB-to-serial converter.
Revision 2 of the Mega 2560 board has a resistor pulling the 8U2 HWB line to
ground, making it easier to put into DFU mode.
Revision 3 of the Arduino board and the current Genuino Mega 2560 have
the following improved

features:

• Pin out: SDA and SCL pins - near to the AREF pin - and two other new pins
placed near to the RESET pin, the IOREF that allow the shields to adapt to
the voltage provided from the board. In future, shields will be compatible both
with the board that use the AVR, which operate with 5V and with the board
that uses ATSAM3X8E, that operate with 3.3V. The second one is a not
connected pin, which is reserved for future purposes.
• Stronger RESET circuit.
• Atmega 16U2 replace the 8U2
LCD:

LCD (Liquid Crystal Display) is the innovation utilized in scratch pad shows
and other littler PCs. Like innovation for light-producing diode (LED) and gas-
plasma, LCDs permit presentations to be a lot more slender than innovation for
cathode beam tube (CRT). LCDs expend considerably less power than LED shows
and gas shows since they work as opposed to emanating it on the guideline of
blocking light.

A LCD is either made with a uninvolved lattice or a showcase network

for dynamic framework show. Likewise alluded to as a meager film transistor (TFT)
show is the dynamic framework LCD. The uninvolved LCD lattice has a matrix of
conductors at every crossing point of the network with pixels. Two conductors on
the lattice send a current to control the light for any pixel. A functioning framework
has a transistor situated at every pixel crossing point, requiring less current to control
the luminance of a pixel.

Some aloof network LCD's have double filtering, which implies they
examine the matrix twice with current in the meantime as the first innovation took
one sweep. Dynamic lattice, be that as it may, is as yet a higher innovation.

A 16x2 LCD show is an essential module that is generally utilized in various

gadgets and circuits. These modules more than seven sections and other multi
fragment LEDs are liked. The reasons being: LCDs are affordable; effectively
programmable; have no restriction of showing exceptional and even custom
characters (not at all like in seven fragments), movements, etc. The directions given
to the LCD are put away by the order register. An order is a direction given to LCD
to play out a predefined assignment, for example, introducing it, clearing its screen,
setting the situation of the cursor, controlling presentation, and so forth.
Data/Signals/Execution of LCD
Now that was all about the signals and the hardware. Let us come to data, signals
and execution.

Two types of signals are accepted by LCD, one is data and one is control. The LCD
module recognizes these signals from the RS pin status. By pulling the R / W pin
high, data can now also be read from the LCD display. Once the E pin has been
pulsed, the LCD display reads and executes data at the falling edge of the pulse, the
same for the transmission case.

It takes 39-43μS for the LCD display to place a character or execute a command. It
takes 1.53ms to 1.64ms except for clearing display and searching for cursor to the
home position.

Any attempt to send data before this interval may result in failure in some devices
to read data or execute the current data. Some devices compensate for the speed by
storing some temporary registers with incoming data.

There are two RAMs for LCD displays, namely DDRAM and CGRAM. DDRAM
registers the position in which the character would be displayed in the ASCII chart.
Each DDRAM byte represents every single position on the display of the LCD.

The DDRAM information is read by the LCD controller and displayed on the LCD
screen. CGRAM enables users to define their personalized characters. Address space
is reserved for users for the first 16 ASCII characters.
Images of LCD Display:

LCD – Front View

LCD – Back View

Pin Diagram:
Pin Description:
Pin
Function Name
No
1 Ground (0V) Ground
2 Supply voltage; 5V (4.7V – 5.3V) Vcc
3 Contrast adjustment; through a variable resistor VEE
Selects command register when low; and data register Register
4
when high Select
Low to write to the register; High to read from the
5 Read/write
register
Sends data to data pins when a high to low pulse is
6 Enable
given
7 DB0
8 DB1
9 DB2
10 DB3
8-bit data pins
11 DB4
12 DB5
13 DB6
14 DB7
15 Backlight VCC (5V) Led+
16 Backlight Ground (0V) Led-

RS (Register select)
A 16X2 LCD has two order and information registers. The determination of the
register is utilized to change starting with one register then onto the next. RS=0 for
the register of directions, while RS=1 for the register of information.

Command Register
The guidelines given to the LCD are put away by the direction register. An order is
a direction given to LCD to play out a predefined assignment, for example, instating
it, clearing its screen, setting the situation of the cursor, controlling showcase, and
so on. Order preparing happens in the direction register.
Data Register:

The information register will store the information that will be shown on
the LCD. The information is the character's ASCII incentive to show on the LCD. It
goes to the information register and is prepared there when we send information to
the LCD. While choosing RS=1, the information register.

Read and Write Mode of LCD:

As stated, the LCD itself comprises of an interface IC. This interface IC

can be perused or composed by the MCU. A large portion of the occasions we're
simply going to keep in touch with the IC since perusing will make it increasingly
perplexing and situations like that are exceptionally uncommon.Information such as
cursor position, status completion interrupts, etc. can be read if necessary.

LCD Commands:

There are some preset commands in the LCD that we need to send to the LCD via
some microcontroller. The following are some important command instructions:
 Sr. No. Hex Code Command to LCD instruction Register

1 01 Clear display screen

2 02 Return home

3 04 Decrement cursor (shift cursor to left)

4 06 Increment cursor (shift cursor to right)

5 05 Shift display right

6 07 Shift display left

7 08 Display off, cursor off

8 0A Display off, cursor on

9 0C Display on, cursor off

10 0E Display on, cursor blinking

11 0F Display on, cursor blinking

12 10 Shift cursor position to left

13 14 Shift cursor position to right

14 18 Shift the entire display to the left

15 1C Shift the entire display to the right

16 80 Force cursor to beginning ( 1st line)

17 C0 Force cursor to beginning ( 2nd line)

18 38 2 lines and 5×7 matrix

Introduction

• It is used for many applications like wireless headset, game controllers,

wireless mouse, wireless keyboard and many more consumer applications.
• It has range up to <100m which depends upon transmitter and receiver,
atmosphere, geographic & urban conditions.
• It is IEEE 802.15.1 standardized protocol, through which one can build
wireless Personal Area Network (PAN). It uses frequency-hopping spread
spectrum (FHSS) radio technology to send data over air.
• It uses serial communication to communicate with devices. It communicates
with microcontroller using serial port (USART).

HC-05 Bluetooth Module

• HC-05 is a Bluetooth module which is designed for wireless communication.

This module can be used in a master or slave configuration.

HC-05 Bluetooth Module

Pin Description

Bluetooth serial modules allow all serial enabled devices to communicate with each
other using Bluetooth.

It has 6 pins,

1. Key/EN: It is used to bring Bluetooth module in AT commands mode. If Key/EN

pin is set to high, then this module will work in command mode. Otherwise by
default it is in data mode. The default baud rate of HC-05 in command mode is
38400bps and 9600 in data mode.

HC-05 module has two modes,

1. Data mode: Exchange of data between devices.

2. Command mode: It uses AT commands which are used to change setting

of HC-05. To send these commands to module serial (USART) port is used.

2. VCC: Connect 5 V or 3.3 V to this Pin.

3. GND: Ground Pin of module.

4. TXD: Transmit Serial data (wirelessly received data by Bluetooth module

transmitted out serially on TXD pin)
5. RXD: Receive data serially (received data will be transmitted wirelessly by
Bluetooth module).

6. State: It tells whether module is connected or not.

HC-05 module Information

• HC-05 has red LED which indicates connection status, whether the Bluetooth
is connected or not. Before connecting to HC-05 module this red LED blinks
continuously in a periodic manner. When it gets connected to any other
Bluetooth device, its blinking slows down to two seconds.
• This module works on 3.3 V. We can connect 5V supply voltage as well since
the module has on board 5 to 3.3 V regulator.
• As HC-05 Bluetooth module has 3.3 V level for RX/TX and microcontroller
can detect 3.3 V level, so, no need to shift transmit level of HC-05 module.
But we need to shift the transmit voltage level from microcontroller to RX of
HC-05 module.
Bluetooth communication between Devices

E.g., Send data from Smartphone terminal to HC-05 Bluetooth module and see this
data on PC serial terminal and vice versa.

To communicate smartphone with HC-05 Bluetooth module, smartphone requires

Bluetooth terminal application for transmitting and receiving data. You can find
Bluetooth terminal applications for android and windows in respective app. store.

Bluetooth Module Serial Interface

So, when we want to communicate through smartphone with HC-05

Bluetooth module, connect this HC-05 module to the PC via serial to USB converter.

Before establishing communication between two Bluetooth devices, 1st we need to

pair HC-05 module to smartphone for communication.
Pair HC-05 and smartphone:

1. Search for new Bluetooth device from your phone. You will find Bluetooth
device with “HC-05” name.
2. Click on connect/pair device option; default pin for HC-05 is 1234 or 0000.

After pairing two Bluetooth devices, open terminal software (e.g.

Teraterm, Realterm etc.) in PC, and select the port where we have connected USB
to serial module. Also select default baud rate of 9600 bps.In smart phone, open
Bluetooth terminal application and connect to paired device HC-05.

It is simple to communicate, we just have to type in the Bluetooth terminal

application of smartphone. Characters will get sent wirelessly to Bluetooth module
HC-05. HC-05 will automatically transmit it serially to the PC, which will appear on
terminal. Same way we can send data from PC to smartphone.

Command Mode

• When we want to change settings of HC-05 Bluetooth module like change

password for connection, baud rate, Bluetooth device’s name etc.
• To do this, HC-05 has AT commands.
• To use HC-05 Bluetooth module in AT command mode, connect “Key” pin
to High (VCC).
• Default Baud rate of HC-05 in command mode is 38400bps.
• Following are some AT command generally used to change setting of
Bluetooth module.
• To send these commands, we have to connect HC-05 Bluetooth module to the
PC via serial to USB converter and transmit this command through serial
terminal of PC.
 Command Description Response

AT Checking communication OK

Set Password
AT+PSWD=XXXX OK
e.g. AT+PSWD=4567

Set Bluetooth Device

Name
AT+NAME=XXXX OK
e.g. AT+NAME=MyHC-
05

AT+UART=Baud
Change Baud rate
rate, stop bit, parity OK
e.g. AT+UART=9600,1,0
bit

+Version: XX OK
Respond version no. of
AT+VERSION? e.g. +Version: 2.0
Bluetooth module
20130107 OK

Parameters: device type, module

Send detail of setting done
AT+ORGL mode, serial parameter,
by manufacturer
passkey,etc.
Motor Driver:

A motor driver is an integrated circuit chip which is usually used to control

motors in autonomous robots. Motor driver act as an interface between Arduino and
the motors. The most commonly used motor driver IC’s are from the L293 series
such as L293D, L293NE, etc. These ICs are designed to control 2 DC motors
simultaneously. L293D consist of two H-bridge. H-bridge is the simplest circuit for
controlling a low current rated motor. We will be referring the motor driver IC as
L293D only. L293D has 16 pins.

The L293D is a 16 pin IC, with eight pins, on each side, dedicated to the controlling
of a motor. There are 2 INPUT pins, 2 OUTPUT pins and 1 ENABLE pin for each
motor. L293D consist of two H-bridge. H-bridge is the simplest circuit for
controlling a low current rated motor.
 Pin Pin Name Description
Number
1 Enable 1,2 This pin enables the input pin Input 1(2) and Input 2(7)
2 Input 1 Directly controls the Output 1 pin. Controlled by digital
circuits
3 Output 1 Connected to one end of Motor 1
4 Ground Ground pins are connected to ground of circuit (0V)
5 Ground Ground pins are connected to ground of circuit (0V)
6 Output 2 Connected to another end of Motor 1
7 Input 2 Directly controls the Output 2 pin. Controlled by digital
circuits
8 Vcc2 (Vs) Connected to Voltage pin for running motors (4.5V to 36V)
9 Enable 3,4 This pin enables the input pin Input 3(10) and Input 4(15)
10 Input 3 Directly controls the Output 3 pin. Controlled by digital
circuits
11 Output 3 Connected to one end of Motor 2
12 Ground Ground pins are connected to ground of circuit (0V)
13 Ground Ground pins are connected to ground of circuit (0V)
14 Output 4 Connected to another end of Motor 2
15 Input 4 Directly controls the Output 4 pin. Controlled by digital
circuits
16 Vcc2 Connected to +5V to enable IC function
(Vss)
Working of L293D

There are 4 input pins for l293d, pin 2, 7 on the left and pin 15, 10 on the right as
shown on the pin diagram. Left input pins will regulate the rotation of motor
connected across left side and right input for motor on the right hand side. The
motors are rotated on the basis of the inputs provided across the input pins as LOGIC
0 or LOGIC 1.

In simple you need to provide Logic 0 or 1 across the input pins for rotating the
motor.

L293D Logic Table.

Let’s consider a Motor connected on left side output pins (pin 3, 6). For rotating the
motor in clockwise direction the input pins has to be provided with Logic 1 and
Logic 0.

Pin 2 = Logic 1 and Pin 7 = Logic 0 | Clockwise Direction

Pin 2 = Logic 0 and Pin 7 = Logic 1 | Anticlockwise Direction

Pin 2 = Logic 0 and Pin 7 = Logic 0 | Idle [No rotation] [Hi-Impedance state]

Pin 2 = Logic 1 and Pin 7 = Logic 1 | Idle [No rotation]

Circuit Diagram for l293d motor driver IC controller

Voltage Specification

VCC is the voltage that it needs for its own internal operation 5v; L293D will not
use this voltage for driving the motor. For driving the motors it has a separate
provision to provide motor supply VSS (V supply). L293d will use this to drive the
motor. It means if you want to operate a motor at 9V then you need to provide a
Supply of 9V across VSS Motor supply.

The maximum voltage for VSS motor supply is 36V. It can supply a max current of
600mA per channel. Since it can drive motors Up to 36v hence you can drive pretty
big motors with this l293d. VCC pin 16 is the voltage for its own internal Operation.
The maximum voltage ranges from 5v and up to 36v.
What is a DC Motor?

A direct current (DC) motor is a type of electric machine that converts electrical
energy into mechanical energy. DC motors take electrical power through direct
current, and convert this energy into mechanical rotation.

DC motors use magnetic fields that occur from the electrical currents generated,
which powers the movement of a rotor fixed within the output shaft. The output
torque and speed depends upon both the electrical input and the design of the motor.

How DC motors work

The term ‘DC motor’ is used to refer to any rotary electrical machine that converts
direct current electrical energy into mechanical energy. DC motors can vary in size
and power from small motors in toys and appliances to large mechanisms that power
vehicles, pull elevators and hoists, and drive steel rolling mills.

But how do DC motors work?

DC motors include two key components: a stator and an armature. The stator is
the stationary part of a motor, while the armature rotates. In a DC motor, the stator
provides a rotating magnetic field that drives the armature to rotate.

A simple DC motor uses a stationary set of magnets in the stator, and a coil of wire
with a current running through it to generate an electromagnetic field aligned with
the centre of the coil. One or more windings of insulated wire are wrapped around
the core of the motor to concentrate the magnetic field.
The windings of insulated wire are connected to a commutator (a rotary electrical
switch), that applies an electrical current to the windings. The commutator allows
each armature coil to be energised in turn, creating a steady rotating force (known
as torque).

When the coils are turned on and off in sequence, a rotating magnetic field is created
that interacts with the differing fields of the stationary magnets in the stator to create
torque, which causes it to rotate. These key operating principles of DC motors allow
them to convert the electrical energy from direct current into mechanical energy
through the rotating movement, which can then be used for the propulsion of objects.

Who invented the DC motor?

This amazing piece of electrical equipment has revolutionised our lives in many
ways, but who invented the DC motor? As with all major innovations, there are many
people who had a role to play through the development of similar mechanisms.

In the US, Thomas Davenport is widely celebrated as the inventor of the first electric
motor, and undoubtedly he was the first to patent a useable electric motor in 1837.
Davenport, however, was not the first person to build an electric motor, with various
inventors in Europe having already developed more powerful versions by the time
Davenport filed his patent.

In 1834, Moritz Jacobi had presented a motor that was three times as powerful as the
one Davenport would later patent, while Sibrandus Stratingh and Christopher Becker
were the first to demonstrate a practical application for an electric motor, by running
a small model car in 1835.
The first practical DC motor was invented some years later in 1886 by Frank Julian
Sprague, whose invention lead to the first motor powered trolley system in 1887,
and the first electric elevator in1892. Sprague’s DC motor was a hugely significant
development, leading to a variety of applications which would reshape the face of
industry and manufacturing.

Types of DC Motors

So far, this guide has broadly explained how DC motors work, the history of
these mechanisms, and what they look like. While the principles are the same across
variants, there are actually several different types of DC motors, which offer specific
advantages and disadvantages over each other.
 Ultrasonic sensor

An ultrasonic sensor transmit ultrasonic waves into the air and detects reflected
waves from an object. There are many applications for ultrasonic sensors, such as in
intrusion alarm systems, automatic door openers and backup sensors for
automobiles.

Accompanied by the rapid development of information processing

technology, new fields of application, such as factory automation equipment and car
electronics, are increasing and should continue to do so. Using its unique
piezoelectric ceramics manufacturing technology developed over many years,
Murata has developed various types of ultrasonic sensors which are compact and yet
have very high performance. The information contained in this catalog will help you to make
effective use of our ultrasonic sensors.

HC-SR04 Sensor Features

• Operating voltage: +5V

• Theoretical Measuring Distance: 2cm to 450cm
• Practical Measuring Distance: 2cm to 80cm
• Accuracy: 3mm
• Measuring angle covered: <15°
• Operating Current: <15m
• Operating Frequency: 40Hz
•
HC-SR04 Ultrasonic Sensor - Working

As shown above the HC-SR04 Ultrasonic (US) sensor is a 4 pin module, whose pin
names are Vcc, Trigger, Echo and Ground respectively. This sensor is a very popular
sensor used in many applications where measuring distance or sensing objects are
required. The module has two eyes like projects in the front which forms the
Ultrasonic transmitter and Receiver. The sensor works with the simple high school
formula that

Distance = Speed × Time

The Ultrasonic transmitter transmits an ultrasonic wave, this wave travels in air and
when it gets objected by any material it gets reflected back toward the sensor this
reflected wave is observed by the Ultrasonic receiver module as shown in the picture
below

Now, to calculate the distance using the above formulae, we should know the Speed
and time. Since we are using the Ultrasonic wave we know the universal speed of
US wave at room conditions which is 330m/s. The circuitry inbuilt on the module
will calculate the time taken for the US wave to come back and turns on the echo
pin high for that same particular amount of time, this way we can also know the time
taken. Now simply calculate the distance using a microcontroller or microprocessor.
How to use the HC-SR04 Ultrasonic Sensor

HC-SR04 distance sensor is commonly used with both microcontroller

and microprocessor platforms like Arduino, ARM, PIC, Raspberry Pie etc. The
following guide is universally since it has to be followed irrespective of the type of
computational device used.

Power the Sensor using a regulated +5V through the Vcc ad Ground pins of the
sensor. The current consumed by the sensor is less than 15mA and hence can be
directly powered by the on board 5V pins (If available). The Trigger and the Echo
pins are both I/O pins and hence they can be connected to I/O pins of the
microcontroller. To start the measurement, the trigger pin has to be made high for
10uS and then turned off. This action will trigger an ultrasonic wave at frequency of
40Hz from the transmitter and the receiver will wait for the wave to return. Once the
wave is returned after it getting reflected by any object the Echo pin goes high for a
particular amount of time which will be equal to the time taken for the wave to return
back to the sensor.

The amount of time during which the Echo pin stays high is measured by the
MCU/MPU as it gives the information about the time taken for the wave to return
back to the Sensor. Using this information the distance is measured as explained in
the above heading.
Servo Motor:

A servo motor is a type of motor that can rotate with great precision.
Normally this type of motor consists of a control circuit that provides feedback on
the current position of the motor shaft, this feedback allows the servo motors to
rotate with great precision. If you want to rotate an object at some specific angles or
distance, then you use a servo motor. It is just made up of a simple motor which runs
through a servo mechanism. If motor is powered by a DC power supply, then it is
called DC servo motor, and if it is AC-powered motor then it is called AC servo
motor. Apart from these major classifications, there are many other types of servo
motors based on the type of gear arrangement and operating characteristics. A servo
motor usually comes with a gear arrangement that allows us to get a very high torque
servo motor in small and lightweight packages. Due to these features, they are being
used in many applications like toy car, RC helicopters and planes, Robotics, etc.

Servo motors are rated in kg/cm (kilogram per centimeter) most hobby servo motors
are rated at 3kg/cm or 6kg/cm or 12kg/cm. This kg/cm tells you how much weight
your servo motor can lift at a particular distance. For example: A 6kg/cm Servo
motor should be able to lift 6kg if the load is suspended 1cm away from the motors
shaft, the greater the distance the lesser the weight carrying capacity. The position
of a servo motor is decided by electrical pulse and its circuitry is placed beside the
motor.
Servo Motor Working Mechanism

It consists of three parts:

1. Controlled device
2. Output sensor
3. Feedback system
It is a closed-loop system where it uses a positive feedback system to control motion
and the final position of the shaft. Here the device is controlled by a feedback signal
generated by comparing output signal and reference input signal.

Here reference input signal is compared to the reference output signal and the third
signal is produced by the feedback system. And this third signal acts as an input
signal to the control the device. This signal is present as long as the feedback signal
is generated or there is a difference between the reference input signal and reference
output signal. So the main task of servomechanism is to maintain the output of a
system at the desired value at presence of noises.
Servo Motor Working Principle

A servo consists of a Motor (DC or AC), a potentiometer, gear assembly, and a

controlling circuit. First of all, we use gear assembly to reduce RPM and to increase
torque of the motor. Say at initial position of servo motor shaft, the position of the
potentiometer knob is such that there is no electrical signal generated at the output
port of the potentiometer. Now an electrical signal is given to another input terminal
of the error detector amplifier. Now the difference between these two signals, one
comes from the potentiometer and another comes from other sources, will be
processed in a feedback mechanism and output will be provided in terms of error
signal. This error signal acts as the input for motor and motor starts rotating. Now
motor shaft is connected with the potentiometer and as the motor rotates so the
potentiometer and it will generate a signal. So as the potentiometer’s angular
position changes, its output feedback signal changes. After sometime the position of
potentiometer reaches at a position that the output of potentiometer is same as
external signal provided. At this condition, there will be no output signal from the
amplifier to the motor input as there is no difference between external applied signal
and the signal generated at potentiometer, and in this situation motor stops rotating.
Relay:

What is a relay?

A relay is an electromagnetic switch that is used to turn on and turn off a circuit by
a low power signal, or where several circuits must be controlled by one signal.

Most of the high end industrial application devices have relays for their effective
working. Relays are simple switches which are operated both electrically and
mechanically. Relays consist of an electromagnet and also a set of contacts. The
switching mechanism is carried out with the help of the electromagnet. There are
also other operating principles for its working. But they differ according to their
applications. Most of the devices have the application of relays.

Pin Diagram:
Why is a relay used?

control a circuit. It is also used in places where only one signal can be used to
control a lot of circuits. The application of relays started during the invention of
telephones. They played an important role in switching calls in telephone exchanges.
They were also used in long distance telegraphy. They were used to switch the signal
coming from one source to another destination. After the invention of computers
they were also used to perform Boolean and other logical operations. The high end
applications of relays require high power to be driven by electric motors and so on.
Such relays are called The main operation of a relay comes in places where only a
low-power signal can be used to contactors.

Relay Design

• There are only four main parts in a relay. They are

• Electromagnet
• Movable Armature
• Switch point contacts
• Spring

The figures given below show the actual design of a simple relay.

Relay Construction
It is an electro-magnetic relay with a wire coil, surrounded by an iron core.
A path of very low reluctance for the magnetic flux is provided for the
movable armature and also the switch point contacts.

The movable armature is connected to the yoke which is mechanically

connected to the switch point contacts. These parts are safely held with
the help of a spring. The spring is used so as to produce an air gap in the
circuit when the relay becomes de-energized.

How relay works?

The relay function can be better understood by explaining the following diagram
given below.

Relay Design
The diagram shows an inner section diagram of a relay. An iron core is surrounded
by a control coil. As shown, the power source is given to the electromagnet through
a control switch and through contacts to the load. When current starts flowing
through the control coil, the electromagnet starts energizing and thus intensifies the
magnetic field. Thus the upper contact arm starts to be attracted to the lower fixed
arm and thus closes the contacts causing a short circuit for the power to the load. On
the other hand, if the relay was already de-energized when the contacts were closed,
then the contact move oppositely and make an open circuit.

As soon as the coil current is off, the movable armature will be returned by a force
back to its initial position. This force will be almost equal to half the strength of the
magnetic force. This force is mainly provided by two factors. They are the spring
and also gravity.

Relays are mainly made for two basic operations. One is low voltage application and
the other is high voltage. For low voltage applications, more preference will be given
to reduce the noise of the whole circuit. For high voltage applications, they are
mainly designed to reduce a phenomenon called arcing
 Relay Basics

The basics for all the relays are the same. Take a look at a 4 pin relay shown below.
There are two colors shown. The green color represents the control circuit and the
red color represents the load circuit. A small control coil is connected onto the
control circuit. A switch is connected to the load. This switch is controlled by the
coil in the control circuit. Now let us take the different steps that occur in a relay.

Relay operation
• Energized Relay (ON)

As shown in the circuit, the current flowing through the coils represented by pins 1
and 3 causes a magnetic field to be aroused. This magnetic field causes the closing
of the pins 2 and 4. Thus the switch plays an important role in the relay working. As
it is a part of the load circuit, it is used to control an electrical circuit that is connected
to it. Thus, when the electrical relay in energized the current flow will be through
the pins 2 and 4.
 Energized Relay (ON)
• De – Energized Relay (OFF)
As soon as the current flow stops through pins 1 and 3, the relay switch
opens and thus the open circuit prevents the current flow through pins 2 and 4.
Thus the relay becomes de-energized and thus in off position.

De-Energized Relay (OFF)

 In simple, when a voltage is applied to pin 1, the electromagnet activates, causing a
magnetic field to be developed, which goes on to close the pins 2 and 4 causing a
closed circuit. When there is no voltage on pin 1, there will be no electromagnetic
force and thus no magnetic field. Thus the switches remain open.

Pole and Throw

Relays have the exact working of a switch. So, the same concept is also applied. A
relay is said to switch one or more poles. Each pole has contacts that can be thrown
in mainly three ways. They are

• Normally Open Contact (NO): NO contact is also called a make contact. It closes
the circuit when the relay is activated. It disconnects the circuit when the relay is
inactive.
• Normally Closed Contact (NC): NC contact is also known as break contact. This
is opposite to the NO contact. When the relay is activated, the circuit disconnects.
When the relay is deactivated, the circuit connects.
• Change-over (CO) / Double-throw (DT) Contacts: This type of contacts are used
to control two types of circuits. They are used to control a NO contact and also a NC
contact with a common terminal. According to their type they are called by the
names break before make and make before break contacts.

Relays can be used to control several circuits by just one signal. A relay switches
one or more poles, each of whose contacts can be thrown by energizing the coil.
 Relays are also named with designations like

• Single Pole Single Throw (SPST): The SPST relay has a total of four terminals.
Out of these two terminals can be connected or disconnected. The other two
terminals are needed for the coil to be connected.
• Single Pole Double Throw (SPDT): The SPDT relay has a total of five terminals.
Out of these two are the coil terminals. A common terminal is also included which
connects to either of two others.
• Double Pole Single Throw (DPST): The DPST relay has a total of six terminals.
These terminals are further divided into two pairs. Thus they can act as two SPST
which are actuated by a single coil. Out of the six terminals two of them are coil
terminals.
• Double Pole Double Throw (DPDT): The DPDT relay is the biggest of all. It has
mainly eight relay terminals. Out of these two rows are designed to be change over
terminals. They are designed to act as two SPDT relays which are actuated by a
single coil.
Relay Applications
• A relay circuit is used to realize logic functions. They play a very important role in
providing safety critical logic.
• Relays are used to provide time delay functions. They are used to time the delay
open and delay close of contacts.
• Relays are used to control high voltage circuits with the help of low voltage signals.
Similarly they are used to control high current circuits with the help of low current
signals.
• They are also used as protective relays. By this function all the faults during
transmission and reception can be detected and isolated.
 Application of Overload Relay

Overload relay is an electro-mechanical device that is used to safeguard motors from

overloads and power failures. Overload relays are installed in motors to safeguard
against sudden current spikes that may damage the motor. An overload relay switch
works in characteristics with current over time and is different from circuit breakers
and fuses, where a sudden trip is made to turn off the motor. The most widely used
overload relay is the thermal overload relay where a bimetallic strip is used to turn
off the motor. This strip is set to make contact with a contactor by bending itself with
rising temperatures due to excess current flow. The contact between the strip and the
contactor causes the contactor to de-energize and restricts the power to the motor,
and thus turns it off.

Another type of overload motor is the electronic type which continuously watches
the motor current, whereas the thermal overload relay shuts off the motor depending
on the rise of temperature/heat of the strip.

All overload relays available to buy comes in different specifications, the most
important of them being the current ranges and response time. Most of them are
designed to automatically reset to work after the motor is turned back on.
 Relay Selection

You must note some factors while selecting a particular relay. They are

• Protection Different protections like contact protection and coil protection must be
noted. Contact protection helps in reducing arcing in circuits using inductors. Â Coil
protection helps in reducing surge voltage produced during switching.
• Look for a standard relay with all regulatory approvals.
• Switching time Ask for high speed switching relays if you want one.
• Ratings There are current as well as voltage ratings. The current ratings vary from a
few amperes to about 3000 amperes. Â In case of voltage ratings, they vary from
300 Volt AC to 600 Volt AC. There are also high voltage relays of about 15,000
Volts.
• Type of contact used whether it is a NC or NO or closed contact.
• Select Make before Break or Break before Make contacts wisely.
• Isolation between coil circuit and contacts

Solar panel:

• Photovoltaic solar panels absorb sunlight as a source of energy to generate

electricity. A photovoltaic (PV) module is a packaged, connected assembly of
typically 6x10 photovoltaic solar cells. Photovoltaic modules constitute the
photovoltaic array of a photovoltaic system that generates and supplies solar
electricity in commercial and residential applications.
• The most common application of solar energy collection outside agriculture
is solar water heating systems.
• Theory and construction
• Photovoltaic modules use light energy (photons) from the Sun to generate
electricity through the photovoltaic effect. The majority of modules use wafer-
based crystalline silicon cells or thin-film cells. The structural (load carrying)
member of a module can either be the top layer or the back layer. Cells must
also be protected from mechanical damage and moisture. Most modules are
rigid, but semi-flexible ones based on thin-film cells are also available. The
cells must be connected electrically in series, one to another.
• A PV junction box is attached to the back of the solar panel and it is its output
interface. Externally, most of photovoltaic modules use MC4 connectors type
to facilitate easy weatherproof connections to the rest of the system. Also,
USB power interface can be used.
• Module electrical connections are made in series to achieve a desired output
voltage or in parallel to provide a desired current capability (amperes). The
conducting wires that take the current off the modules may contain silver,
copper or other non-magnetic conductive transition metals. Bypass diodes
may be incorporated or used externally, in case of partial module shading, to
maximize the output of module sections still illuminated.
• Some special solar PV modules include concentrators in which light is
focused by lenses or mirrors onto smaller cells. This enables the use of cells
with a high cost per unit area (such as gallium arsenide) in a cost-effective
way.
• Solar panels also use metal frames consisting of racking components,
brackets, reflector shapes, and troughs to better support the panel structure.
 Technology:

• Most solar modules are currently produced from crystalline silicon (c-Si) solar
cells made of multicrystalline and monocrystalline silicon. In 2013, crystalline
silicon accounted for more than 90 percent of worldwide PV production,
while the rest of the overall market is made up of thin-film technologies using
cadmium telluride, CIGS and amorphous silicon[16]
• Emerging, third generation solar technologies use advanced thin-film cells.
They produce a relatively high-efficiency conversion for the low cost
compared to other solar technologies. Also, high-cost, high-efficiency, and
close-packed rectangular multi-junction (MJ) cells are preferably used in solar
panels on spacecraft, as they offer the highest ratio of generated power per
kilogram lifted into space. MJ-cells are compound semiconductors and made
of gallium arsenide (GaAs) and other semiconductor materials. Another
emerging PV technology using MJ-cells is concentrator photovoltaics (CPV)

Thin film

• In rigid thin-film modules, the cell and the module are manufactured in the
same production line. The cell is created on a glass substrate or superstrate,
and the electrical connections are created in situ, a so-called "monolithic
integration". The substrate or superstrate is laminated with an encapsulant to
a front or back sheet, usually another sheet of glass. The main cell
technologies in this category are CdTe, or a-Si, or a-Si+uc-Si tandem, or CIGS
(or variant). Amorphous silicon has a sunlight conversion rate of 6–12%
• Flexible thin film cells and modules are created on the same production line
by depositing the photoactive layer and other necessary layers on a flexible
substrate. If the substrate is an insulator (e.g. polyester or polyimide film) then
monolithic integration can be used. If it is a conductor then another technique
for electrical connection must be used. The cells are assembled into modules
by laminating them to a transparent colourless fluoropolymer on the front side
(typically ETFE or FEP) and a polymer suitable for bonding to the final
substrate on the other side.
Power supply:

A power supply is a component that provides at least one electrical charge with
power. It typically converts one type of electrical power to another, but it can also
convert a different Energy form in electrical energy, such as solar, mechanical, or
chemical.

A power supply provides electrical power to components. Usually the term refers to
devices built into the powered component. Computer power supplies, for example,
convert AC current to DC current and are generally located along with at least one
fan at the back of the computer case.

Most computer power supplies also have an input voltage switch that, depending on
the geographic location, can be set to 110v/115v or 220v/240v. Due to the different
power voltages supplied by power outlets in different countries, this switch position
is crucial.

Some basic components used in the supply of power:

Transformer:

A transformer is a static electrical gadget that exchanges control between at least

two circuits. A fluctuating current creates a changing attractive motion in one
transformer curl, which thus actuates a differing electromotive power over a second
loop twisted around a similar center.

Without a metallic association between the two circuits, electrical vitality can be
exchanged between the two loops. The enlistment law of Faraday found in 1831
portrayed the impact of prompted voltage in any curl because of the changing
attractive flux surrounded by the coil.

Circuit of transformer

Transformer
Rectifier:

A rectifier is an electrical device that converts alternating current (AC), which

periodically reverses direction, to direct current (DC), which flows in only one
direction. The process is known as rectification, since it "straightens" the direction
of current.

Rectifiers have many uses, but are often found to serve as components of DC power
supplies and direct power transmission systems with high voltage. Rectification can
be used in roles other than direct current generation for use as a power source.

Circuit of rectifier

Rectifier
Capacitors:

Capacitors are used to attain from the connector the immaculate and smoothest DC
voltage in which the rectifier is used to obtain throbbing DC voltage which is used
as part of the light of the present identity. Capacitors are used to acquire square DC
from the current AC experience of the current channels so that they can be used as a
touch of parallel yield.

Capacitor
Voltage regulators:
The 78XX voltage controller is mainly used for voltage controllers as a whole. The
XX speaks to the voltage delivered to the specific gadget by the voltage controller
as the yield. 7805 will supply and control 5v yield voltage and 12v yield voltage will
be created by 7812.

The voltage controllers are that their yield voltage as information requires no less
than 2 volts. For example, 7805 as sources of information will require no less than
7V, and 7812, no less than 14 volts. This voltage is called Dropout Voltage, which
should be given to voltage controllers.

7805 voltage regulator with pinout

7812 voltage regulator with pinout

EMBEDDED C

Implanted C makes use of KEIL IDE programming. The framework program

written in implanted C can be placed away in Microcontroller. The accompanying is
a portion of the actual motives behind composing applications in C as opposed to
get collectively. It is much less disturbing and much less tedious to write down in C
then amassing. C is less traumatic to trade and refresh. You can utilize code available
in capacity libraries. C code is compact to different microcontrollers with subsequent
to 0 alteration. Genuine, installed C programming need nonstandard expansions to
the C driver with a view to bolster charming components, as an example, settled
point range catching, numerous unmistakable reminiscence banks, and fundamental
I/O operations.

In 2008, the C Standards Committee prolonged the C data to deal with these
problems via giving a normal well known to all executions to purchaser to contains
numerous additives not handy in standard C, for example, settled factor wide variety
catching, named address spaces, and vital I/O equipment tending to.

Installed C utilize the greater part of the grammar and semantics of wellknown
C, e.G., number one() paintings, variable definition, facts type statement, contingent
proclamations (if, switch. Case), circles (even as, for), capacities, exhibits and
strings, structures and union, piece operations, macros, unions, and so on.
Embedded systems programming

Installed frameworks writing computer programs is not quite the same as creating
applications on a desktop PCs. Key attributes of an implanted framework, when
contrasted with PCs, are as per the following:
•Embedded gadgets have asset limitations (restricted ROM, constrained RAM,
constrained stack space, less handling power)
•Components utilized as a part of installed framework and PCs are distinctive;
implanted frameworks ordinarily utilizes littler, less power devouring segments.
Inserted frameworks are more fixing to the equipment.
Two remarkable components of Embedded Programming are code speed and
code estimate. Code speed is represented by the handling power, timing
requirements, while code size is administered by accessible program memory and
utilization of programming dialect. Objective of implanted framework writing
computer programs is to get greatest elements in least space and least time.

Implanted frameworks are modified utilizing distinctive sort of dialects:

•Machine Code
•Low level dialect, i.e., get together
•High level dialect like C, C++, and Java and so on.
•Application level dialect like Visual Basic, scripts, Access, and so on..,
Arduino IDE:

The Arduino IDE software is a open source software, where we can have the
example codes for the beginners. In the Present world there are lot of version in the
Arduino IDE in which present usage is Version1.0.5. It is very easy to connect the
PC with Arduino Board.

First we have to install the Arduino IDE software according to the below
instructions:

 Insert the CD-ROM or PENDRIVE which Contains the software and then
Copy the Setup File to your desired location.
 After Copying, now click on the setup you will see an window shown below
 Click On NO, not this time. Then after NEXT
  Another Window opens –select Install from a list of specific location and
NEXT

 Select “include this location in the search” and then click Browse option
available in it

 Now it will Automatically check the USB driver and the software is installed
click Finish
.

 Now click Finish, the Software will be downloaded.

 Now click on the Arduino IDE icon present on your Desktop. A window will
appear like this.
 For any sample programs, select FILE optionExamples.

 After Entering the Sample Code in the file, it would look like this
 Before Connecting we have to select which Board is used by the user,
Basically UNO. By selecting TOOLSBoardARDUINO UNO

 Now to dump the in the board Connect the Arduino to the PC through the
USB port available in it. Like this TOOLSSERIAL
 PORTCOMM4,COMM8 etc;

 To verify the written Program select COMPILE option available in the

software (√).
 Now Connect the Board and select the COMM port and then UPLOAD the
file in ARDUINO()
 To OPEN the Previous ARDUINO FILE selects (↑) option.
 To enter new files select NEW option.
 To Save the Existing File, Click on the(↓).
 To Send the Data Through Serial Monitor, Click on the (Ǫ).
 Here we can see the Serial Data.
Conclusion

This project introduces wireless technology in the field of agriculture. Exploits

features of Android platform to help Farmers Significantly. Provides a flexible user
interface to farmer to control the machine effectively. It reduces manual labor
requirement which is a boon to the farmers as finding laborers is a very difficult job
today. The Agribot can work in any sort of climatic condition as well as can work
nonstop unlike humans. The time required to carry out the five functionalities
reduces considerably in comparison with carrying out the same activities manually.
It is a onetime investment which reduces the overall farming cost considerably. This
Agribot acts as a gateway to automated smart farming.
References

[1] “Agricultural Robot for Automatic Ploughing and Seeding” 2015 IEEE
International Conference on Technological Innovations in ICT (TIAR 2015)
(Amrita Sneha.A, Abirami.E, Ankita.A, Mrs. R. Praveen, Mrs. R. Srimeena).

[2] “Design and Implementation of Seeding Agricultural Robot” (JIRAS) (P.Usha,

V. Maheswari, Dr. V. Nandagopal)

[3]. “Automated Farming Using Microcontroller and Sensors” (IJSRMS) ISSN:

23493371 (Abdullah Tanveer, Abhishek Choudhary, Divya Pal, Rajani Gupta,
Farooq Husain)

[4] “IOT Based Smart Agriculture” IJARCCE June 2016 (Nikesh Gondchawar1,
Prof. Dr. R. S. Kawitkar2)

[5] Sachin .D.Khirade, A.B.patil,” Plant disease detection Using image

processing,”2015, International conference on computing communication control
and automation, IEEE.

[6] Vijai singh, Varsha, A.K.Mishra,”Detection of unhealthy region of plant leaves

using image processing and genetic algorithm”, 205, ICA CEA, India.

[7] Monica Jhuria, Ashwani kumar and Rushikesh Borse, ”Image processing for
Smart farming, detection of Disease and Fruit Grading,” proceeding of the 2013,
IEEE, second international conference on image Information processing.

[8] Mrunalani .R.Badnakhe,Prashant .R.Deshmukh,”Infected leaf analysis and

comparison by otsu threshold and K means clustering, ”International journal of
advanced research in computer science and software engineering,volu me2,Issue
3,march 2012.