Home Automation Using Telegram.docx

HOME AUTOMATION

ABSTRACT

CHAPTER 1 INTRODUCTION Embedded systems: An Embedded system is a combination of computer hardware and software. As with any electronic system, this system requires a hardware platform and that is built with a microprocessor or microcontroller. The Embedded system hardware includes elements like user interface, Input/Output interfaces, display and memory, etc. Generally, an embedded system comprises power supply, processor, memory, timers, serial communication ports and system application specific circuits.

Embedded system software is written in a high-level language, and then compiled to achieve a specific function within a non-volatile memory in the hardware. Embedded system software is designed to keep in view of three limits. They are availability of system memory and processor speed. When the system runs endlessly, there is a need to limit the power dissipation for events like run, stop and wake up. Types of Embedded Systems Embedded systems can be classified into different types based on performance, functional requirements and performance of the microcontroller.

Types of Embedded systems Embedded systems are classified into four categories based on their performance and functional requirements: 

Stand alone embedded systems



Real time embedded systems



Networked embedded systems



Mobile embedded systems

Embedded Systems are classified into three types based on the performance of the microcontroller such as 

Small scale embedded systems



Medium scale embedded systems



Sophisticated embedded systems

1. Stand Alone Embedded Systems Stand alone embedded systems do not require a host system like a computer, it works by itself. It takes the input from the input ports either analog or digital and processes, calculates and converts the data and gives the resulting data through the connected device-Which either controls, drives and displays the connected devices. Examples for the stand alone embedded systems are mp3 players, digital cameras, video game consoles, microwave ovens and temperature measurement systems.

2. Real Time Embedded Systems A real time embedded system is defined as, a system which gives a required o/p in a particular time. These types of embedded systems follow the time deadlines for completion of a task. Real time embedded systems are classified into two types such as soft and hard real time systems. 3. Networked Embedded Systems These types of embedded systems are related to a network to access the resources. The connected network can be LAN, WAN or the internet. The connection can be any wired or wireless. This type of embedded system is the fastest growing area in embedded system applications. The embedded web server is a type of system wherein all embedded devices are connected to a web server and accessed and controlled by a web browser. Example for the LAN networked embedded system is a home security system wherein all sensors are connected and run on the protocol TCP/IP 4. Mobile Embedded Systems Mobile embedded systems are used in portable embedded devices like cell phones, mobiles, digital cameras, mp3 players and personal digital assistants, etc. The basic limitation of these devices is the other resources and limitation of memory. 1. Small Scale Embedded Systems These types of embedded systems are designed with a single 8 or 16-bit microcontroller, that may even be activated by a battery. For developing embedded software for small scale embedded systems, the main programming tools are an editor, assembler, cross assembler and integrated development environment (IDE).

2. Medium Scale Embedded Systems These types of embedded systems design with a single or 16 or 32 bit microcontroller, RISCs or DSPs. These types of embedded systems have both hardware and software complexities. For developing embedded software for medium scale embedded systems, the main programming tools are C, C++, JAVA, Visual C++, RTOS, debugger, source code engineering tool, simulator and IDE. 3. Sophisticated Embedded Systems These types of embedded systems have enormous hardware and software complexities, that may need ASIPs, IPs, PLAs, scalable or configurable processors. They are used for cuttingedge applications that need hardware and software Co-design and components which have to assemble in the final system.

APPLICATIONS OF EMBEDDED SYSTEMS: Embedded systems are used in different applications like automobiles, telecommunications, smart cards, missiles, satellites, computer networking and digital consumer electronics. Embedded Systems in Automobiles and in telecommunications 

Motor and cruise control system



Body or Engine safety



Entertainment and multimedia in car



E-Com and Mobile access



Robotics in assembly line



Wireless communication



Mobile computing and networking

Embedded Systems in Smart Cards, Missiles and Satellites.



Security systems



Telephone and banking



Defense and aerospace



Communication

Embedded Systems in Peripherals & Computer Networking 

Displays and Monitors



Networking Systems



Image Processing



Network cards and printers

Embedded Systems in Consumer Electronics 

Digital Cameras



Set top Boxes



High Definition TVs



DVDs

This is all about the embedded systems, types of embedded systems with their applications. We all know that these systems are extremely fabulous systems that play a vital role in many devices, equipments, industrial control systems, industrial instrumentation and home appliances irrespective of circuit complexity. Considering the huge significance of embedded systems, this embedded systems article deserves readers’ feedback, queries, suggestions and comments. Furthermore, for any queries regarding electronics project kits, readers can post their comments in the comment section below.

Microcontroller It’s like a small computer on a single IC. It contains a processor core, ROM, RAM and I/O pins dedicated to perform various tasks. Microcontrollers are generally used in projects and applications that require direct control of user. As it has all the components needed in its single chip, it does not need any external circuits to do its task so microcontrollers are heavily used in embedded systems and major microcontroller manufacturing companies are making them to be used in embedded market. A microcontroller can be called the heart of embedded system. Some examples of popular microcontrollers are 8051, AVR, PIC series of microcontrollers,.

Microprocessor Microprocessor has only a CPU inside them in one or few Integrated Circuits. Like microcontrollers it does not have RAM, ROM and other peripherals. They are dependent on external circuits of peripherals to work. But microprocessors are not made for specific task but they are required where tasks are complex and

tricky like development of software’s, games and other applications that require high memory and where input and output are not defined. It may be called heart of a computer system. Some examples of microprocessor are Pentium, I3, and I5 etc.

What is the difference between microprocessor and microcontroller? As now you are basically aware of what is a microcontroller and microprocessor, it would be easy to identify the major differences between a microcontroller and microprocessor. 1. Key difference in both of them is presence of external peripheral, where microcontrollers have RAM, ROM, EEPROM embedded in it while we have to use external circuits in case of microprocessors.

2. As all the peripheral of microcontroller are on single chip it is compact while microprocessor is bulky.

3. Microcontrollers are made by using complementary metal oxide semiconductor technology so they are far cheaper than microprocessors. In addition the applications made with microcontrollers are cheaper because they need lesser external components, while the overall cost of systems made with microprocessors are high because of the high number of external components required for such systems.

4. Processing speed of microcontrollers is about 8 MHz to 50 MHz, but in contrary processing speed of general microprocessors is above 1 GHz so it works much faster than microcontrollers.

5. Generally microcontrollers have power saving system, like idle mode or power saving mode so overall it uses less power and also since external components are low overall consumption of power is less. While in microprocessors generally there is no power saving system and also many external components are used with it, so its power consumption is high in comparison with microcontrollers.

6. Microcontrollers are compact so it makes them favorable and efficient system for small products and applications while microprocessors are bulky so they are preferred for larger applications.

7. Tasks performed by microcontrollers are limited and generally less complex. While task performed by microprocessors are software development, Game development, website, documents making etc. which are generally more complex so require more memory and speed so that’s why external ROM, RAM are used with it.

8. Microcontrollers are based on Harvard architecture where program memory and data memory are separate while microprocessors are based on von Neumann model where program and data are stored in same memory module.

CHAPTER2 BLOCK DIAGRAM

RASPBERRY PI RASPBERRY PI

RELAY 1

LOAD 1

RELAY 2

LOAD 2

RELAY 3

L293D IC

LOAD 3

DOOR

CHAPTER3 HARDWARE COMPONENTS REGULATED POWER SUPPLY

Regulated power supply section In mains-supplied electronic systems the AC input voltage must be converted into a DC voltage with the right value and degree of stabilization. In these basic configurations the peak voltage across the load is equal to the peak value of the AC voltage supplied by the transformer’s secondary winding. For most applications the output ripple produced by these circuits is too high. However, for some applications - driving small motors or lamps, for example - they are satisfactory. If a filter capacitor is added after the rectifier diodes the output voltage waveform is improved considerably. The section b-c is a straight line. During this time it is the filter capacitor that supplies the load current. The slope of this line increases as the current increases, bringing point c lower. Consequently the diode conduction time (c-d) increases, increasing ripple. With zero load current the DC output voltage is equal to the peak value of the rectified AC voltage. Figure shows how to obtain positive and negative outputs referred to a common ground. In particular they are helpful in determining the voltage ripple for a given load current and filter capacitor value. The value of the voltage ripple obtained is directly proportional to the load current and inversely proportional to the filter capacitor value. The performance of a supply commonly used in consumer applications – in audio amplifiers. Often the degree of stability provided by the circuits described above is insufficient and a stabilizer circuit is needed. This circuit is often used as a reference voltage to apply to the base of a transistor of to the input of an op amp to obtain higher output current. The simplest example of a series regulator is shown in Figure. In this circuit the transistor is connected as a voltage follower and the output voltage is about 600 - 700mV lower than the zener voltage.

The resistor R must be dimensioned so that the zener is correctly biased and that sufficient base current is supplied to the base of Q1. For high load currents the base current of Q1 is no longer negligible. To avoid that the current in the zener drops to the point where effective regulation is not possible a Darlington may be used in place of the transistor. When better performance is required the op amp circuit shown in Figure is recommended. In this circuit the output voltage is equal to the reference voltage applied to the input of the op amp. With a suitable output buffer higher currents can be obtained. The output voltage of the Figure 14 circuit can be varied by adding a variable divider in parallel with the zener diode and with its wiper connected to the op amp’s input. The design of stabilized supplies has been simplified dramatically by the introduction of voltage regulator ICs such as the L78xx and L79xx - three-terminal series regulators which provide a very stable output and include current limiter and thermal protection functions. Regulated power supply is mainly used to providing power to this project because it is providing regulated dc power and it converts 220v ac supply into regulated dc power of 5v, 9v, 12v, 15v etc. Regulated power supply consists of step down transformer, bridge rectifier which is combination of 4 diodes connected in bridge shape. Bridge rectifier has the maximum efficiency and it is best than other rectifiers that’s why we prefer it. This rectifier converts ac into pulsating dc. After rectifier filter circuit is employed, usually capacitor in parallel is used as filter or we can use number of capacitors in parallel and number of inductors in series. All these filters are low pass filters as we required dc at the o/p. Then after capacitor voltage regulator is used for observing the pure dc o/p. We can use various voltage regulators for obtaining pure dc o/p but we prefer 78xx series voltage regulators as they are simpler, cheaper and easier than others.

Fig. 2.1: Circuit diagram of regulated power supply section

1) AC Input: This is the input supply from the public utility where the device will be energized. It is also supplied directly to the relay contacts in the device which connects the load to the supply when the supply is within 200V – 240V range.

(2) Step down transformer: It steps down the AC supply into 5v on the secondary side. It is therefore a 230/5 v transformer. Any change in the primary reflects in the secondary of the transformer. So any fluctuations in the input are also reflected as a fluctuation in the output.

(3) Rectifier: A center tapped transformer, with four diodes for full wave rectification is used to convert the ac voltage to a pulsating dc voltage followed by a filter, comprising of a capacitor to filter out (smooth) the pulsation. After the rectification and smoothening, a sample of the output voltage is fed to the micro controller. This voltage is unregulated and therefore varies as the input mains voltage varies. Since the system is to prevent against over voltage, the transformer was designed and the windings were so selected for the device to be able to sense and withstand input mains voltage up to 600Vac.

MODULES

BASIC COMPONENTS IN MICROCONTROLLER BOARD 1. Diode In electronics, a diode is a component that restricts the direction of movement of charge carriers. Essentially, it allows an electric current to flow in one direction, but blocks it in the opposite direction. Today the most common diodes are made from semiconductor materials such as silicon or germanium.

Fig. : Diode

2. Semiconductor Diodes Most modern diodes are based on semiconductor P-N junctions. In a P-N diode, conventional current can flow from the P-type side (the anode) to the N-type side (the cathode), but not in the opposite direction. A semiconductor diode s current-voltage, or I-V, characteristic curve is ascribed to the behavior of the so-called depletion layer or depletion zone which exists at the P-N junction between the differing semiconductors. When a P-N junction is first created, conduction band (mobile) electrons from the N-doped region diffuse into the P-doped region where there is a large population of holes (places for electrons in which no electron is present) with which the electrons recombine. When a mobile electron recombines with a hole, the hole vanishes and the electron is no longer mobile. Thus, two charge carriers have vanished. The region around the P-N junction becomes depleted of charge carriers and thus behaves as an insulator.

1N4001 and 1N5400 series diodes The 1N4001 series (or 1N4000 series) is a family of popular 1.0 amp general purpose silicon rectifier diodes commonly used in AC adapters for common household appliances. Blocking voltage varies from 50 to 1000 volts. This diode is made in an axial-lead DO-41 plastic package. The 1N5400 series is a similarly popular series for higher current applications, up to 3 A. These diodes come in the larger DO-201 axial package. These are fairly low-speed rectifier diodes, being inefficient for square waves of more than 15 kHz. The series was second sourced by many manufacturers. The 1N4000 series were in the Motorola Silicon Rectifier Handbook in 1966, as replacements for 1N2609 through 1N2617. The 1N5400 series were announced in Electrical Design News in 1968, along with the now lesser known 1.5-ampere 1N5391 series. These devices are widely used and recommended. The table below shows the maximum repetitive reverse blocking voltages of each of the members of the 1N4000 and 1N5400 series.

TABLE .1. Diode part Numbers for different currents and voltages VOLTAGE 1A PART 3A PART 50V

1N4001

1N5400

100V

1N4002

1N5401

200V

1N4003

1N5402

300V 400V 500V

_ 1N4004 _

1N5403 1N5404 1N5405

600V

1N4005

1N5406

800V

1N4006

1N5407

1000V

1N4007

1N5408

3. Voltage regulator 7805 Voltage regulator 5V DC Voltage Regulator Data Sheet / Specs

The 7805 provides circuit designers with an easy way to regulate DC voltages to 5v.

Fig. : Voltage Regulator Encapsulated in a single chip/package (IC), the 7805 is a positive voltage DC regulator that has only 3 terminals. They are: Input voltage, Ground, Output Voltage. Although the 7805 were primarily designed for a fixed-voltage output (5V). 7812 Voltage regulator 12V DC Voltage Regulator Data Sheet / Specs. The 78012 provides circuit designers with an easy way to regulate DC voltages to 12v. Encapsulated in a single chip/package (IC), the 78012 is a positive voltage DC regulator that has only 3 terminals. They are: Input voltage, Ground, Output Voltage. Although the 78012 were primarily designed for a fixed-voltage output (12V). 7812 Voltage regulator. It is indeed possible to use external components in order to obtain DC output voltages of: 5V, 6V, 8V, 9V, 10V, 12V, 15V, 18V, 20V, 24V. Note that the input voltage must, of course, be greater than the required output voltage, so that it can be regulated downwards.

4. Capacitor In the Regulated power supply the rating of the chosen capacitor filter is 1000µF.A capacitor (originally known as condenser) is a passive two-terminal electrical component used to store energy in an electric field. The forms of practical capacitors vary widely, but all contain at least

two electrical conductors separated by a dielectric (insulator); for example, one common construction consists of metal foils separated by a thin layer of insulating film. Capacitors are widely used as parts of electrical circuits in many common electrical devices. When there is a potential difference (voltage) across the conductors, a static electric field develops across the dielectric, causing positive charge to collect on one plate and negative charge on the other plate. Energy is stored in the electrostatic field. An ideal capacitor is characterized by a single constant value, capacitance, measured in farads. This is the ratio of the electric charge on each conductor to the potential difference between them.

Fig. : Capacitor The capacitance is greatest when there is a narrow separation between large areas of conductor, hence capacitor conductors are often called "plates," referring to an early means of construction. In practice, the dielectric between the plates passes a small amount of leakage current and also has an electric field strength limit, resulting in a breakdown voltage, while the conductors and leads introduce an undesired inductance and resistance. Capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass, in filter networks, for smoothing the output of power supplies, in the resonant circuits that tune radios to particular frequencies, in electric power transmission systems for stabilizing voltage and power flow, and for many other purposes.

5. Resistors A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. The current through a resistor is in direct proportion to the voltage across the resistor's terminals. Thus, the ratio of the voltage applied across a resistor's terminals

to the intensity of current through the circuit is called resistance. This relation is represented by Ohm's law: where I is the current through the conductor in units of amperes, V is the potential difference measured across the conductor in units of volts, and R is the resistance of the conductor in units of ohms. More specifically, Ohm's law states that the R in this relation is constant, independent of the current. Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in electronic equipment. Practical resistors can be made of various compounds and films, as well as resistance wire (wire made of a high-resistivity alloy, such as nickel-chrome). Resistors are also implemented within integrated circuits, particularly analog devices, and can also be integrated into hybrid and printed circuits.

Fig. : Resistor The electrical functionality of a resistor is specified by its resistance: common commercial resistors are manufactured over a range of more than nine orders of magnitude. When specifying that resistance in an electronic design, the required precision of the resistance may require attention to the manufacturing tolerance of the chosen resistor, according to its specific application. The temperature coefficient of the resistance may also be of concern in some precision applications. Practical resistors are also specified as having a maximum power rating which must exceed the anticipated power dissipation of that resistor in a particular circuit: this is mainly of concern in power electronics applications. Resistors with higher power ratings are physically larger and may require heat sinks. In a high-voltage circuit, attention must sometimes be paid to the rated maximum working voltage of the resistor.

6. Crystal RED LEDs LED is an acronym for Light Emitting Diode. Well, you ask, what on earth is a diode. A diode is a device that, in simplest terms, allows electricity to flow through one way but not the

other. Those of you who are knowledgeable about mechanical things could think of it as sort of a check valve. If you have no mechanical knowledge, disregard that last sentence. Now that you know what a diode is, an LED is just one that emits light (But you could probably figure that out just from reading the name). Another important thing about all LED's (and all diodes) is that every one of them has exactly two electrodes. These are important to know when you are wiring an LED into a circuit. They are the... Anode - The p-side which is the longer leg. Cathode - Which is the n-side and shorter leg. Since you know these terms you can remember that electricity flows easily from the anode to the cathode but not the other way around. LED's are great for many reasons. First of all, they don't heat up like regular light bulbs do. This is great because, well, you don't burn yourself. They are also smaller than a light bulb. Another important thing about LED's is that they run on very low amounts of electricity, which is helpful because it makes them safer to work with (you don't electrocute yourself). Most run on about 20mA. Just like with everything, there are some tips that are helpful to make sure your LED's work well. Clip the leads - Simple, I know, but people forget to. This is important because it prevents them from bumping into other parts and messing up your circuit. Remember which electrode is which - This is a big one because if you don't it won't work at all. It's a diode; current only flows through it one way. Read the package - Simple again, but each LED requires slightly different voltage and ampere. It always helps to wire a resistor into your circuit. It will make the LED last longer by dropping the voltage. There are some sites that make it easy to find which resistor you need. LEDs come in all sorts of sizes as well. Here is a photo showing a 3mm, 5mm and 10mm LED. The "millimeter" size refers to the diameter of the LED. For example, if you need to drill a hole in a box for your 5mm blink LED, the hole-size should be 5mm, and you'd need a 5mm drill bit to

make it. 5mm are the most common size you'll see, and they can be extremely bright! Green 3mm, Red 5mm and White 10mm LEDs 

5mm LEDs can be so bright, they are often used as illumination (lighting something up, like a flashlight, we'll talk about this next).



3mm LEDs are not as bright but are smaller, and are good for indication (like an LED that tells you something is on). They're not as good for illumination because they have a smaller area that is lit.



10mm LEDs are a little rarer, they are huge and chunky but are usually just 5mm LEDs with a bigger case so they aren't any brighter. They can be good indicators but we rarely see them as illuminators.

Fig. : Red LED

RELAY

A relay is a device which is operated by a variation in its electrical or physical conditions to effect the operation of other devices in an electric circuit. A protective relay is a relay, the principal function of which is to protect service from interruption or to prevent or limit damage to apparatus. In electrical engineering, a protective relay is a device designed to trip a circuit breaker when a fault is detected. The first protective relays were electromagnetic devices, relying on coils operating on moving parts to provide detection of abnormal operating conditions such as over-current, over-voltage, reverse power flow, over- and under- frequency.

There are always a chance of suffering an electrical power system from abnormal over voltages. These abnormal over voltages may be caused due to various reason such as, sudden interruption of heavy load, lightening impulses, switching impulses etc. These over voltage stresses may damage insulation of various equipments, all the over voltage stresses are not strong enough to damage insulation of system, but still these over voltages also to be avoided to ensure the smooth operation of electrical power system.

TYPES OF OVER VOLTAGE RELAY The below are the types of over voltage relay: Define Time Overvoltage Relay Inverse Time Overvoltage Relay

1. Definite Time Overvoltage Relays In this type, two conditions must be satisfied for operation (tripping), voltage must exceed the setting value and the fault must be continuous at least a time equal to time setting of the relay. Modern relays may contain more than one stage of protection each stage includes each own current and time setting. 1. For Operation of Definite Time Overvoltage Relay operating time is constant 2. Its operation is independent of the magnitude of voltage above the pick-up value. 3. It has pick-up and time dial settings, desired time delay can be set with the help of an intentional time delay mechanism. 4. Easy to coordinate. 5. Constant tripping time independent of in feed variation and fault location. Applications: 1. Back up protection of distance relay of transmission line with time delay. 2. Back up protection to differential relay of power transformer with time delay.

3. Main protection to outgoing feeders and bus couplers with adjustable time delay setting. 2. Inverse Time Overvoltage Relays In this type of relays, operating time is inversely changed with voltage. So, high voltage will operate overvoltage relay faster than lower ones. There are standard inverse, very inverse and extremely inverse types. Discrimination by both ‘Time’ and ‘Voltage’, the relay operation time is inversely proportional to the fault voltage. The operating time of an overvoltage relay can be moved up (made slower) by adjusting the ‘time dial setting’. The lowest time dial setting (fastest operating time) is generally 0.5 and the slowest is 10. • Operates when voltage exceeds its pick-up value. • Operating time depends on the magnitude of voltage. • It gives inverse time voltage characteristics at lower values of fault voltage and definite time characteristics at higher values • An inverse characteristic is obtained if the value of plug setting multiplier is below 10, for values between 10 and 20 characteristics tend towards definite time characteristics.

Normal Inverse Time Overvoltage Relay The accuracy of the operating time may range from 5 to 7.5% of the nominal operating time as specified in the relevant norms. The uncertainty of the operating time and the necessary operating time may require a grading margin of 0.4 to 0.5 seconds. Application: Most frequently used in utility and industrial circuits. especially applicable where the fault magnitude is mainly dependent on the system generating capacity at the time of fault. 2.2 Inverse Time Overvoltage Relay • Gives more inverse characteristics than that of IDMT. • Used where there is a reduction in fault voltage, as the distance from source increases. • Particularly effective with ground faults because of their steep characteristics. • Suitable if there is a substantial reduction of fault voltage as the fault distance from the power source increases. • Very inverse overvoltage relays are particularly suitable if the short-circuit voltage drops rapidly with the distance from the substation. • The grading margin may be reduced to a value in the range from 0.3 to 0.4 seconds when overvoltage relays with very inverse characteristics are used. • Used when Fault Voltage is dependent on fault location. • Used when Fault Voltage independent of normal changes in generating capacity. CIRCUIT DIAGRAM OF RELAY

L293D IC L293D is a typical Motor driver or Motor Driver IC which allows DC motor to drive on either direction. L293D is a 16-pin IC which can control a set of two DC motors simultaneously in any direction. It means that you can control two DC motor with a single L293D IC. Dual Hbridge Motor Driver integrated circuit (IC).

The l293d can drive small and quiet big motors as well, check the Voltage Specification at the end of this page for more info. Concept: It works on the concept of H-bridge. H-bridge is a circuit which allows the voltage to be flown in either direction. As you know voltage need to change its direction for being able to rotate the motor in clockwise or anticlockwise direction, hence H-bridge IC are ideal for driving a DC motor.

In a single L293D chip there are two h-Bridge circuit inside the IC which can rotate two dc motor independently. Due its size it is very much used in robotic application for controlling DC motors. Given below is the pin diagram of a L293D motor controller. There are two Enable pins on l293d. Pin 1 and pin 9, for being able to drive the motor, the pin 1 and 9 need to be high. For driving the motor with left H-bridge you need to enable pin 1 to high. And for right H-Bridge you need to make the pin 9 to high. If anyone of the either pin1 or pin9 goes low then the motor in the corresponding section will suspend working. It’s like a switch. TIP: you can simply connect the pin16 VCC (5v) to pin 1 and pin 9 to make them high.

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] In a very similar way the motor can also operate across input pin 15, 10 for motor on the right hand side.

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 upto 36v.

RASPBERRY PI 3 MODEL B

The Raspberry Pi is a series of small single-board computers developed in the United Kingdom by the Raspberry Pi Foundation to promote teaching of basic computer science in schools and in developing countries. The original model became far more popular than anticipated, selling outside its target market for uses such as robotics. It does not include peripherals (such as keyboards and mice) and cases. However, some accessories have been included in several official and unofficial bundles.

The organization behind the Raspberry Pi consists of two arms. The first two models were developed by the Raspberry Pi Foundation. After the Pi Model B was released, the Foundation set up Raspberry Pi Trading, with Eben Upton as CEO, to develop the third model, the B+. Raspberry Pi Trading is responsible for developing the technology while the Foundation is an educational charity to promote the teaching of basic computer science in schools and in developing countries. According to the Raspberry Pi Foundation, more than 5 million Raspberry PI is were sold by February 2015, making it the best-selling British computer. By November 2016 they had sold 11 million units, and 12.5m by March 2017, making it the third best-selling "general purpose computer". In July 2017, sales reached nearly 15 million. In March 2018, sales reached 19 million.

Technical Specification: Processor 

Broadcom BCM2387 chipset.



1.2GHz Quad-Core ARM Cortex-A53 (64Bit) b/g/n Wireless LAN and Bluetooth 4.1 (Bluetooth Classic and LE) 

IEEE 802.11 b / g / n Wi-Fi. Protocol: WEP, WPA WPA2, algorithms AESCCMP (maximum key length of 256 bits), the maximum range of 100 meters.



IEEE 802.15 Bluetooth, symmetric encryption algorithm Advanced Encryption Standard (AES) with 128-bit key, the maximum range of 50 meters.

GPU 

Dual Core Video Core IV® Multimedia Co-Processor. Provides Open GL ES 2.0, hardware-accelerated Open VG, and 1080p30 H.264 high-profile decode.



Capable of 1Gpixel/s, 1.5Gtexel/s or 24GFLOPs with texture filtering and DMA infrastructure Memory



1GB LPDDR2 Operating System



Boots from Micro SD card, running a version of the Linux operating system or Windows 10 IoT Dimensions



85 x 56 x 17mm Power



Micro USB socket 5V1, 2.5A

Connectors: Ethernet 

10/100 BaseT Ethernet socket Video Output



HDMI (rev 1.3 & 1.4)



Composite RCA (PAL and NTSC) Audio Output



Audio Output 3.5mm jack



HDMI



USB 4 x USB 2.0 Connector GPIO Connector



40-pin 2.54 mm (100 mil) expansion header: 2x20 strip



Providing 27 GPIO pins as well as +3.3 V, +5 V and GND supply lines Camera Connector



15-pin MIPI Camera Serial Interface (CSI-2) Display Connector



Display Serial Interface (DSI) 15 way flat flex cable connector with two data lanes and a clock lane Memory Card Slot



Push/pull Micro SDIO

The GPU provides Open GL ES 2.0, hardware-accelerated Open VG, and 1080p30 H.264 high-profile decode and is capable of 1Gpixel/s, 1.5Gtexel/s or 24 GFLOPs of general purpose compute. What’s that all mean? It means that if you plug the Raspberry Pi 3 into your HDTV, you could watch BluRay quality video, using H.264 at 40MBits/s

The biggest change that has been enacted with the Raspberry Pi 3 is an upgrade to a next generation main processor and improved connectivity with Bluetooth Low Energy (BLE) and BCM43143 Wi-Fi on board. Additionally, the Raspberry Pi 3 has improved power management, with an upgraded switched power source up to 2.5 Amps, to support more powerful external USB devices. The Raspberry Pi 3’s four built-in USB ports provide enough connectivity for a mouse, keyboard, or anything else that you feel the RPi needs, but if you want to add even more you can still use a USB hub. Keep in mind, it is recommended that you use a powered hub so as not to overtax the on-board voltage regulator. Powering the Raspberry Pi 3 is easy, just plug any USB power supply into the micro-USB port. There’s no power button so the Pi will begin to boot as soon as power is applied, to turn it off simply remove power. The four built-in USB ports can even output up to 1.2A enabling you to connect more power hungry USB devices (This does require a 2Amp micro USB Power Supply)

On top of all that, the low-level peripherals on the Pi make it great for hardware hacking. The 0.1" spaced 40-pin GPIO header on the Pi gives you access to 27 GPIO, UART, I2C, SPI as well as 3.3 and 5V sources. Each pin on the GPIO header is identical to its predecessor the Model B+.

SoC Built specifically for the new Pi 3, the Broadcom BCM2837 system-on-chip (SoC) includes four high-performance ARM Cortex-A53 processing cores running at 1.2GHz with 32kB Level 1 and 512kB Level 2 cache memory, a VideoCore IV graphics processor, and is linked to a 1GB LPDDR2 memory module on the rear of the board.

GPIO The Raspberry Pi 3 features the same 40-pin general-purpose input-output (GPIO) header as all the Pis going back to the Model B+ and Model A+. Any existing GPIO hardware will work without modification; the only change is a switch to which UART is exposed on the GPIO’s pins, but that’s handled internally by the operating system.

USB chip The Raspberry Pi 3 shares the same SMSC LAN9514 chip as its predecessor, the Raspberry Pi 2, adding 10/100 Ethernet connectivity and four USB channels to the board. As before, the SMSC chip connects to the SoC via a single USB channel, acting as a USB-to-Ethernet adaptor and USB hub.

Antenna There’s no need to connect an external antenna to the Raspberry Pi 3. Its radios are connected to this chip antenna soldered directly to the board, in order to keep the size of the device to a minimum. Despite its diminutive stature, this antenna should be more than capable of picking up wireless LAN and Bluetooth signals – even through walls.

Key Improvements from Pi 2 Model B to Pi 3 Model B: 

Next Generation QUAD Core Broadcom BCM2837 64bit ARMv7 processor



Processor speed has increased from 900MHz on Pi 2 to 1.25Ghz on the RPi 3 Model B



BCM43143 Wi-Fi on board



Bluetooth Low Energy (BLE) on board



Upgraded switched power source up to 2.5 Amps (can now power even more powerful devices over USB ports)

The main differences are the quad core 64-bit CPU and on-board Wi-Fi and Bluetooth. The RAM remains 1GB and there is no change to the USB or Ethernet ports. However, the upgraded power management should mean the Pi 3 can make use of more power hungry USB devices

For Raspberry Pi 3, Broadcom have supported us with a new SoC, BCM2837. This retains the same basic architecture as its predecessors BCM2835 and BCM2836, so all those projects and tutorials which rely on the precise details of the Raspberry Pi hardware will continue to work. The 900MHz 32-bit quad-core ARM Cortex- A7 CPU complex has been replaced by a custom-hardened 1.2GHz 64-bit quad-core ARM Cortex-A53 In terms of size it is identical to the B+ and Pi 2. All the connectors and mounting holes are in the same place so all existing add-ons, HATs and cases should fit just fine although the power and activity LEDs have moved to make room for the WiFi antenna. The performance of the Pi 3 is roughly 50-60% faster than the Pi 2 which means it is ten times faster than the original Pi. All of the connectors are in the same place and have the same functionality, and the board can still be run from a 5V micro-USB power adapter. This time round, we’re recommending a 2.5A adapter if you want to connect power-hungry USB devices to the Raspberry Pi.

Key Improvements from Pi 2 Model B to Pi 3 Model B: 

Next Generation QUAD Core Broadcom BCM2837 64bit ARMv7 processor



Processor speed has increased from 900MHz on Pi 2 to 1.25Ghz on the RPi 3 Model B



BCM43143 Wi-Fi on board



Bluetooth Low Energy (BLE) on board



Upgraded switched power source up to 2.5 Amps (can now power even more powerful devices over USB ports)

The main differences are the quad core 64-bit CPU and on-board Wi-Fi and Bluetooth. The RAM remains 1GB and there is no change to the USB or Ethernet ports. However,

the upgraded power management should mean the Pi 3 can make use of more power hungry USB devices For Raspberry Pi 3, Broadcom have supported us with a new SoC, BCM2837. This retains the same basic architecture as its predecessors BCM2835 and BCM2836, so all those projects and tutorials which rely on the precise details of the Raspberry Pi hardware will continue to work. The 900MHz 32-bit quad-core ARM Cortex- A7 CPU complex has been replaced by a custom-hardened 1.2GHz 64-bit quad-core ARM Cortex-A53 In terms of size it is identical to the B+ and Pi 2. All the connectors and mounting holes are in the same place so all existing add-ons, HATs and cases should fit just fine although the power and activity LEDs have moved to make room for the WiFi antenna. The performance of the Pi 3 is roughly 50-60% faster than the Pi 2 which means it is ten times faster than the original Pi. All of the connectors are in the same place and have the same functionality, and the board can still be run from a 5V micro-USB power adapter. This time round, we’re recommending a 2.5A adapter if you want to connect power-hungry USB devices to the Raspberry Pi.

Raspberry Pi

Raspberry Pi

3 Model B

2 Model B

Processor Chipset Broadcom BCM2837

64Bit

Model A+

Model A

Broadcom

Broadcom

Broadcom

Broadcom

BCM2836

32bit BCM2835

BCM2835

BCM2835

32bit

32bit

ARMv7 Quad Core

ARMv7 Quad Core 32bit

Processor

Processor

powered

Single

GPU

Model B+

Board

powered

Single

Board

ARMv6

SoC

ARMv6

SoC

ARMv6

SoC

full

HD

full

HD

full

HD

Computer running at

Computer running at

multimedia

multimedia

multimedia

1250MHz

900MHz

applications

applications

applications

processor

processor

processor

Videocore IV

Videocore IV

Videocore IV

Videocore IV

Videocore IV

Processor Speed

QUAD

Core

QUAD @900 MHz

1GB SDRAM @ 400

Single

Core

@700 MHz

Single

Core

Single

Co

@700 MHz

@700 MHz

1GB SDRAM @ 400 512 MB SDRAM

256 MB SDRAM

256 MB SDRAM

MHz

MHz

@ 400 MHz

@ 400 MHz

@ 400 MHz

Storage

MicroSD

MicroSD

MicroSD

MicroSD

SDCard

USB 2.0

4x USB Ports

4x USB Ports

4x USB Ports

1x USB Port

1x USB Port

Power Draw

2.5A @ 5V

1.8A @ 5V

1.8A @ 5V

1.8A @ 5V

1.2A @ 5V

GPIO

40 pin

40 pin

40 pin

40 pin

26 pin

Ethernet Port

Yes

Yes

Yes

No

No

Wi-Fi

Built in

No

No

No

No

Bluetooth LE

Built in

No

No

No

No

RAM

@1250 MHz

Core

/ voltage

CHAPTER 4 TELEGRAM Telegram is a cloud-based instant messaging and voice over IP service developed by Telegram

Messenger LLP,

Kingdom, founded Telegram client apps

by

a

privately

held

company

the Russian entrepreneur Pavel are

available

registered

Durov and

his

for Android, iOS, Windows

in London, United brother Nikolai. Phone, Windows

NT, macOS and Linux. Users can send messages and exchange photos, videos, stickers, audio and files of any type. Telegram's client-side code is open-source software but the source code for recent versions is not always immediately published, whereas its server-side code is closed-source and proprietary. The service also provides APIs to independent developers. In March 2018, Telegram stated that it had 200 million monthly active users. According to its CEO, as of April 2017, Telegram’s annual growth rate was greater than 50%. Messages and media in Telegram are only client-server encrypted and stored on the servers by default. The service provides end-to-end encryption for voice calls,[24] and optional end-to-end encrypted "secret" chats between two online users, yet not for groups or channels. Telegram's security model has received notable criticism by cryptography experts. They criticized the general security model of permanently storing all contacts, messages and media together with their decryption keys on its servers by default and by not enabling end-to-end encryption for messages by default. Pavel Durov has argued that this is because it helps to avoid third-party unsecure backups, and to allow users to access messages and files from any device. Cryptography experts have furthermore criticized Telegram's use of a custom-designed encryption protocol that has not been proven reliable and secure. Telegram has faced censorship or outright bans in some countries over accusations that the app's services have been used to facilitate illegal activities, such as protests and terrorism, as well as declining demands to facilitate government access to user data and communications.

Security Cryptography experts have expressed both doubts and criticisms on Telegram's MTProto encryption scheme, saying that deploying home-brewed and unproven cryptography may render the encryption vulnerable to bugs that potentially undermine its security, due to a lack of scrutiny. It has also been suggested that Telegram did not employ developers with sufficient expertise or credibility in this field. Critics have also disputed claims by Telegram that it is "more secure than mass market messengers like WhatsApp and Line", because WhatsApp applies end-to-end encryption to all of its traffic by default and uses the Signal Protocol, which has been "reviewed and endorsed by leading security experts", while Telegram does neither and insecurely stores all messages, media and contacts in their cloud. Since July 2016, Line has also applied end-to-end encryption to all of its messages by default. On 26 February 2014, the German consumer organization Stiftung Warentest evaluated several data-protection aspects of Telegram, along with other popular instant-messaging clients. Among the aspects considered were: the security of the data transmission, the service's terms of use, the accessibility of the source code and the distribution of the app. Telegram was rated 'critical' (kritisch) overall. The organization was favorable to Telegram's secure chats and partially open source code, but criticized the mandatory transfer of contact data to Telegram's servers and the lack of an imprint or address on the service's website. It noted that while the message data is encrypted on the device, it could not analyse the transmission due to a lack of source code. The Electronic Frontier Foundation (EFF) listed Telegram on its "Secure Messaging Scorecard" in February 2015. Telegram's default chat function received a score of 4 out of 7 points on the scorecard. It received points for having communications encrypted in transit, having its code open to independent review, having the security design properly documented, and having completed a recent independent security audit. Telegram's default chat function missed points because the communications were not encrypted with keys the provider didn't have access to, users could not verify contacts' identities, and past messages were not secure if the encryption keys were stolen. Telegram's optional secret chat function, which provides end-to-end encryption, received a score of 7 out of 7 points on the scorecard. The EFF said that the results

"should not be read as endorsements of individual tools or guarantees of their security", and that they were merely indications that the projects were "on the right track". In December 2015, two researchers from Aarhus University published a report in which they demonstrated that MTProto does not achieve indistinguishability under chosen-ciphertext attack (IND-CCA) or authenticated encryption. The researchers stressed that the attack was of a theoretical nature and they "did not see any way of turning the attack into a full plaintextrecovery attack". Nevertheless, they said they saw "no reason why [Telegram] should use a less secure encryption scheme when more secure (and at least as efficient) solutions exist". The Telegram team responded that the flaw does not affect message security and that "a future patch would address the concern". Telegram 4.6, released in December 2017, supports MTProto 2.0, which Telegram claims now satisfied the conditions for IND-CCA.

Account self-destruction

The user is limited.

Telegram accounts are tied to telephone numbers and are verified by SMS or phone call. Users can add multiple devices to their account and receive messages on each one. Connected devices can be removed individually or all at once. The associated number can be changed at any time and when doing so, the user's contacts will receive the new number automatically. In addition, a user can set up an alias that allows them to send and receive messages without exposing their phone number. Telegram accounts can be deleted at any time and they are deleted automatically after six months of inactivity by default, which can optionally be changed to 1 month and 12 months. Users can replace exact "last seen" timestamps with broader messages such as "last seen recently". The default method of authentication that Telegram uses for logins is SMS-based single-factor authentication. All that is needed in order to log into an account and gain access to that user's cloud-based messages is a one-time passcode that is sent via SMS to the user's phone number. These login SMS messages are known to have been intercepted in Iran, Russia and Germany, possibly in coordination with phone companies. Pavel Durov has said that Telegram users in "troubled countries" should enable two-factor authentication by creating passwords, which Telegram allows, but does not require. Cloud-based messages Telegram's default messages are cloud-based and can be accessed on any of the user's connected devices. Users can share photos, videos, audio messages and other files (up to 1.5 gigabyte in size per file). Users can send messages to other users individually or to groups of up to 100,000 members.[63] Sent messages can be edited and deleted on both sides within 48 hours after they have been sent. This gives user an ability to correct typos and retract messages that were sent by mistake. The transmission of messages to Telegram Messenger LLP's servers is

encrypted with the service's MTProto protocol. According to Telegram's privacy policy, "all data is stored heavily encrypted and the encryption keys in each case are stored in several other DCs in different jurisdictions. This way local engineers or physical intruders cannot get access to user data". This makes the messages' security roughly comparable to that of e-mail. Here, most providers employ client-server encryption as well, however usually with the standardized protocol Transport Layer Security. E-mails may or may not be encrypted on the servers. Telegram cloud messages and media remain on the servers at least until deleted by all participants. Bots In June 2015, Telegram launched a platform for third-party developers to create bots. Bots are Telegram accounts operated by programs. They can respond to messages or mentions, can be invited into groups and can be integrated into other programs. It also accepts online payments with credit cards and Apple Pay. Dutch website Tweakers reported that an invited bot can potentially read all group messages when the bot controller changes the access settings silently at a later point in time. Telegram pointed out that it considered implementing a feature that would announce such a status change within the relevant group. Also there are inline bots, which can be used from any chat screen. In order to activate an inline bot, user needs to type in the message field a bot's username and query. The bot then will offer its content. User can choose from that content and send it within a chat. Channels Telegram secure the data about the channel author and subscribers. The admin of the channel can obtain general data about the channel. Each message has its own view counter, showing how many users have seen this message. Channels can be created for broadcasting messages to an unlimited number of subscribers. Channels can be publicly available with an alias and a permanent URL so anyone can join. Users who join a channel can see the entire message history. Users can join and leave channels at any time. Furthermore, users can mute a channel, meaning that the user will still receive messages, but won't be notified. Admin can provide a poll, voting or give permission to post comments on the Telegram channel with help of bots. Stickers

Stickers

are

cloud-based,

high-definition

images

intended

to

provide

more

expressive emoji. When typing in an emoji, the user is offered to send the respective sticker instead. Stickers come in collections called "sets", and multiple stickers can be offered for one emoji. Telegram comes with one default sticker set, but users can install additional sticker sets provided by third-party contributors. Sticker sets installed from one client become automatically available to all other clients. Sticker images use WebP file format, which is better optimized to be transmitted over internet. Drafts Drafts are unfinished messages synced across user devices. One can start typing a message on one device and continue on another. The draft will persist in editing area on any device until it is sent or removed. Secret chats

A "secret chat" confirmation notice - screenshot from Android Marshmallow.

Messages can also be sent with client-to-client encryption in so-called secret chats. These messages are encrypted with the service's MTProto protocol. Unlike Telegram's cloud-based

messages, messages sent within a secret chat can be accessed only on the device upon which the secret chat was initiated and the device upon which the secret chat was accepted; they cannot be accessed on other devices. Messages sent within secret chats can, in principle, be deleted at any time and can optionally self-destruct. Secret chats have to be initiated and accepted by an invitation, upon which the encryption keys for the session are exchanged. Users in a secret chat can verify that no man-in-the-middle attack has occurred by comparing pictures that visualize their public key fingerprints. According to Telegram, secret chats have supported perfect forward secrecy since December 2014. Encryption keys are periodically changed after a key has been used more than 100 times or has been in use for more than a week. Old encryption keys are destroyed. Windows and Linux users are still not able to use secret chats using the official Telegram Desktop app while the official macOS-only client supports them Secret chats are not available for groups or channels. Telegram's local message database is not encrypted by default. Some Telegram clients allow users to encrypt the local message database by setting a passphrase. Voice calls In the end of March 2017, Telegram introduced its own voice calls. The calls are built upon the end-to-end encryption of Secret Chats. Connection is established as peer-topeer whenever possible; otherwise the closest server to the client is used. According to Telegram, there is a neural network working to learn various technical parameters about call to provide better quality of the service for future uses. After a brief initial trial in Western Europe, voice calls are now available for use in most countries. Telescope (video messages) Since version 4.0, released in May 2017, Telegram offers a dedicated video hosting platform called Telescope. The round videos can be up to one minute long and auto play. When posted in a public channel on Telegram, the videos are also uploaded to and viewable without an account at telesco.pe. However, Telegram video messages and "Telescope" videos sent within non-public chats or groups are not published.

Live locations For either 15 minutes, one hour, or eight hours, Telegram users can share their live location in a chat since version 4.4 released in October 2017. If multiple users share their live location within a group, they are shown on an interactive map. Sharing the 'live location' can be stopped at any time. Social login In February 2018, Telegram launched their social login feature to its users, named as Telegram Login. It features a website widget that could be embedded into websites, allowing users to sign into a third party website with their Telegram account. The gateway sends users' Telegram name, username, and profile picture to the website owner, while users' phone number remains hidden. The gateway is integrated with a bot, which is linked with the developer's specific website domain. Passport In July 2018, Telegram introduced their online authorisation and identity management system, Telegram Passport, for platforms that requires real-life identification. It asks users to upload their own official documents such as passport, identity card, driver license, etc. When an online service requires such identification documents and verification, it forwards the information to the platform with the user's permission. Telegram stated that it does not have access to the data, while the platform will only share the information to the authorized recipient. However, the service was criticised for being vulnerable to online brute force attacks

CHAPTER 5 5.1 INSTALLATION STEPS Step 1: Download the Required Software and Files

You need to download 2 software and 1 OS i.e. Raspbian for this complete process. 1st software: The first software is Win32 Disk Imager. https://sourceforge.net/projects/win32diskimager/ 2nd software: Second software is SD Card Formatter. https://www.sdcard.org/downloads/formatter_4/

Raspbian OS: This is the Main operating system of the Pi. https://www.raspberrypi.org/downloads/raspbian/ Extract all files to the desktop.

Step 2: Get the SD Card and the Card Reader

Get a minimum 8GB class 10 SD card with a card reader. Insert that card into the card reader and plug that to the USB port. Step 3: Check the Drive in Which the SD Card Is Mounted Go to my computer or My PC and find the drive name where the SD card is mounted.

Step 4: Format the SD Card

Open SD Card Formatter and select the drive you noticed in the previous step. Click on format and don't alter any other options. When formatting is completed, click on OK. Step 5: Write the OS on the SD Card Open win32diskimager. Browse the .img file of Raspbian OS that was extracted from the downloaded file. Click on open and then click on Write. If any warning pops up then ignore those by clicking OK. Wait for the write to be completed and it may take some minutes. So be patient.

Step 6: Eject the SD Card Now your OS in installed on your Raspberry Pi.

CHAPTER 6 CODE

CHAPTER 7 RESULT

CHAPTER 8 APPLICATION AND ADVANTAGES APPLICATIONS 1. Homes

ADVANTAGES 1. Easy to use and monitor 2. Less power consumption

CHAPTER 9 CONCLUSION

REFERENCES [1] Gareth Mitchell, The Raspberry Pi single-board computer will revolutionize computer science teaching [For & against], Vol.7, NO.3,pp. 26, 2012. [2] Charles Severence, “Eben Upton: Raspberry Pi”, vol.46, NO.10, pp. 14-16, 2013. [3] Raspberry Pi Foundation, http://www.raspberry.org [4] Chris Edwards, “Not-so-humble raspberry pi gets big ideas”, vol.8, NO.3, pp. 30-33, 2013. [5] Matt Richardson and Shawn Wallace, Getting Started with Raspberry [6]Python Software Foundation[US], https://pypi.python.org/pypi