DEVELOPMENT OF WEB ENABLED EMBEDDED SYSTEM FOR COMMERCIAL APPLIANCE
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CHAPTER 1
INTRODUCTION
1.1 MOTIVATION
Electronic mail”often abbreviated as e-mail or email”is a digital communication mechanism, designed primarily for human use, which consists of message content, an author and one or more recipients. It is a facility typically added quickly to any online communication service, whether a single machine or a network. In some other words Email is simply the shortened form of electronic mail, a protocol for receiving, sending and storing electronic messages. Email has gained popularity with the spread of the Internet. In many cases, email has become the preferred method of communication.
This system offers a new approach to control commercial appliances from a remote terminal, with an option from a local server, using the Internet. This system is accomplished by personal computers, microcontroller, ac phase control circuits and microcontroller control software. The system is designed to control 'commercial appliances' on/off, to regulate their output power. The prototype of this system will be designed successfully.
1.2 STATEMENT OF PROBLEM
Now a days the automation field gets a wide growth in the world wide. Under this concept here the project and implimentation is developed. In this project and implimentation the fans, lights, motors and AC are automated by using embedded platform. For instance, if the PC connected to the circuit receive a command to switch on the fan then PC send an interrupt to microcontroller such that microcontroller sends a signal to Driver IC to switch on that device using the help of relay circuit. Similarly we can switch on any device that is connected to microcontroller circuit using E-Mail.
1.3 RELATED WORK
To complete our project and implimentation we studied about PIC 16f877 A controller and its features. We also studied about Sensors, Relays, loads and Relay Drivers. Also we visited sites how stuff works.com, keil.com, google.com.
1.4 SCOPE OF WORK
The project and implimentation DEVELOPMENT OF WEB ENABLED EMBEDDED SYSTEM FOR COMMERCIAL APPLIANCE AND PASSWORD PROTECTED is used in labs, when ever system gets a mail to ON certain device then that device comes to ON position. If the mail gets a interrupt to off a device the device gets automatically off.
CHAPTER-2
BACK GROUND INFORMATION
2.1 INTRODUCTION
The project and implimentation report describes the design Development and Fabrication of One demo unit of the project and implimentation work DEVELOPMENT OF WEB ENABLED EMBEDDED SYSTEM FOR COMMERCIAL APPLIANCE AND PASSWORD PROTECTED by using embedded systems.
Now a day, with the advancement technology, particularly in the field of Microcontrollers, all the activities in our daily living have become a part of Information technology and we find microcontrollers in each and every application. Thus, trend is directing towards Microcontrollers based project and implimentation works. However, in this project and implimentation work two pairs of IR sensors are used to sensing the signals. The microcontroller receives the signal from the sensor. Then the decisions are taken with the help of microcontroller and associated software.
The microcontroller block is playing a major role in this project and implimentation work. The micro controller chip used in this project and implimentation work is PIC 16F877A and this is like heart of the project and implimentation work. The PIC 16F877A microcontroller is a 40-pin IC.
The entire project and implimentation was developed in embedded systems. A system is something that maintains its existence and functions as a whole through the interaction of its parts. E.g. Body, Mankind, Access Control, etc A system is a part of the world that a person or group of persons during some time interval and for some purpose choose to regard as a whole, consisting of interrelated components, each component characterized by properties that are selected as being relevant to the purpose.
¢ Embedded System is a combination of hardware and software used to achieve a single specific task.
¢ Embedded systems are computer systems that monitor, respond to, or control an external environment.
¢ Environment connected to systems through sensors, actuators and other I/O interfaces.
¢ Embedded system must meet timing & other constraints imposed on it by environment.
¢ An embedded system is a microcontroller-based, software driven, reliable, real-time control system, autonomous, or human or network interactive, operating on diverse physical variables and in diverse environments and sold into a competitive and cost conscious market.
An embedded system is not a computer system that is used primarily for processing, not a software system on PC or UNIX, not a traditional business or scientific application. High-end embedded & lower end embedded systems. High-end embedded system - Generally 32, 64 Bit Controllers used with OS. Examples Personal Digital Assistant and Mobile phones etc. Lower end embedded systems - Generally 8, 16 Bit Controllers used with a minimal operating systems and hardware layout designed for the specific purpose. Examples Small controllers and devices in our every day life like Washing Machine, Microwave Ovens, where they are embedded in.
Microcontrollers are embedded inside some other device so that they can control the features or actions of the project and implimentation. Another name for a microcontroller therefore is Embedded Controller. Microcontrollers are dedicated to one task and run one specific program. The program is stored in ROM (read only memory) and generally does not change. Microcontrollers are often low-price devices.
Coming to our project and implimentation whenever the students standing in front of the door for entering in to the lab is sensed by the IR sensor; this signal sends to controller through signal conditioning circuit. The controller takes it as an interrupt signal and gives control signal to the drive unit to open the door. Same like this in side lab if any human being sensed by the controller through IR transceiver it will further turn ON the fans, AC, lights using driver unit.
2.2 PRELIMINARIES
2.2.1 INTRODUCTION TO EMBEDDEDSYSTEMS
Embedded System is a combination of hardware and software used to achieve a single specific task. An embedded system is a microcontroller-based, software driven, reliable, real-time control system, autonomous, or human or network interactive, operating on diverse physical variables and in diverse environments and sold into a competitive and cost conscious market.
BLOCK DIAGRAM FOR EMBEDDED SYSTEM



FIG 2.1 BLOCK DIAGRAM OF EMBEDDED SYSTEM
CLASSIFICATION
¢ Real Time Systems.
¢ RTS is one which has to respond to events within a specified deadline.
¢ A right answer after the dead line is a wrong answer
RTS CLASSIFICATION
¢ Hard Real Time Systems
¢ Soft Real Time System
HARD REAL TIME SYSTEM
¢ "Hard" real-time systems have very narrow response time.
¢ Example: Nuclear power system, Cardiac pacemaker.
SOFT REAL TIME SYSTEM
¢ "Soft" real-time systems have reduced constrains on "lateness" but still must operate very quickly and repeatable.
¢ Example: Railway reservation system “ takes a few extra seconds the data remains valid.
LANGUAGES USED
¢ C
¢ C++
¢ Java
¢ Linux
¢ Ada
¢ Assembly
RAD51 FEATURES
¢ 32-bit native Windows application. Takes advantage of the unlimited memory and flat memory model in the 32-bit environment. Supports long filenames.
¢ Extensible - able to accept tool wizards and plug-ins.
¢ Processors defined in an ASCII controller.cfg file which can be easily expanded to accommodate new microcontrollers.
¢ Tools to help you write assembly code programs. For example, RAD51 generates a symbol table in one of the project and implimentation windowpanes. Click on any symbol and the editor takes you to the place of that symbol™s definition.
¢ Built-in text editor with syntax highlighting.
¢ Project management features. For example, RAD51 supports an environment in which a base code folder holds frequently reused code such as I/O libraries. Individual project and implimentations are subfolders below this folder. The project and implimentations include whichever of the common libraries they need. In this manner you have only one place to keep and maintain the common code, and a logically structured layout for each project and implimentation.
2.2.2 INTRODUCTION TO RELAYS
A relay is usually an electromechanical device that is actuated by an electrical current. The current flowing in one circuit causes the opening or closing of another circuit. Relays are like remote control switches and are used in many applications because of their relative simplicity, long life, and proven high reliability. Relays are used in a wide variety of applications throughout industry, such as in telephone exchanges, digital computers and automation systems. Highly sophisticated relays are utilized to protect electric power systems against trouble and power blackouts as well as to regulate and control the generation and distribution of power. In the home, relays are used in refrigerators, washing machines and dishwashers, and heating and air-conditioning controls. Although relays are generally associated with electrical circuitry, there are many other types, such as pneumatic and hydraulic. Input may be electrical and output directly mechanical, or vice versa.

CHAPTER-3
IMPORTANT APPROACHES TO THE PROJECT
3.1 MICROCONTROLLER
3.1.1 INTRODUCTION TO MICROCONTROLLER
A computer-on-a-chip is a variation of a microprocessor which combines the processor core (CPU), some memory, and I/O (input/output) lines, all on one chip. The computer-on-a-chip is called the microcomputer whose proper meaning is a computer using a (number of) microprocessor(s) as its CPUs, while the concept of the microcomputer is known to be a microcontroller. A microcontroller can be viewed as a set of digital logic circuits integrated on a single silicon chip. This chip is used for only specific applications.
Most microcontrollers do not require a substantial amount of time to learn how to efficiently program them, although many of them, which have quirks, which you will have to understand before you, attempt to develop your first application.
Along with microcontrollers getting faster, smaller and more power efficient they are also getting more and more features. Often, the first version of microcontroller will just have memory and digital I/O, but as the device family matures, more and more pat numbers with varying features will be available.
In this project and implimentation we used PIC 16f877A microcontroller. For most applications, we will be able to find a device within the family that meets our specifications with a minimum of external devices, or an external but which will make attaching external devices easier, both in terms of wiring and programming.
For many microcontrollers, programmers can built very cheaply, or even built in to the final application circuit eliminating the need for a separate circuit. Also simplifying this requirement is the availability of micro-controllers wit SRAM and EEPROM for control store, which will allow program development without having to remove the micro controller fro the application circuit.
3.1.2 MICRO CONTROLLER CORE FEATURES
¢ High-performance RISC CPU.
¢ Only 35 single word instructions to learn.
¢ All single cycle instructions except for program branches which are two cycle.
¢ Operating speed: DC - 20 MHz clock input DC - 200 ns instruction cycle.
¢ Up to 8K x 14 words of FLASH Program Memory, Up to 368 x 8 bytes of Data Memory (RAM) Up to 256 x 8 bytes of EEPROM data memory.
¢ Pin out compatible to the PIC16C73B/74B/76/77
¢ Interrupt capability (up to 14 sources)
¢ Eight level deep hardware stack
¢ Direct, indirect and relative addressing modes.
¢ Power-on Reset (POR).
¢ Power-up Timer (PWRT) and Oscillator Start-up Timer (OST).
¢ Watchdog Timer (WDT) with its own on-chip RC oscillator for reliable operation.
¢ Programmable code-protection.
¢ Power saving SLEEP mode.
¢ Selectable oscillator options.
¢ Low-power, high-speed CMOS FLASH/EEPROM technology.
¢ Fully static design.
¢ In-Circuit Serial Programming (ICSP) .
¢ Single 5V In-Circuit Serial Programming capability.
¢ In-Circuit Debugging via two pins.
¢ Processor read/write access to program memory.
¢ Wide operating voltage range: 2.0V to 5.5V.
¢ High Sink/Source Current: 25 mA.
¢ Commercial and Industrial temperature ranges.
¢ Low-power consumption.
In this project and implimentation we used PIC 16f877A microcontroller. PIC means Peripheral Interface Controller. The PIC family having different series. The series are 12- Series, 14- Series, 16- Series, 18- Series, and 24- Series. We used 16 Series PIC microcontrollers.
3.1.3 ADVANTAGES OF USING A MICROCONTROLLER OVER A MICROPROCESSOR
A designer will use a Microcontroller to
¢ Gather input from various sensors
¢ Process this input into a set of actions
¢ Use the output mechanisms on the Microcontroller to do something useful
¢ RAM and ROM are inbuilt in the MC.
¢ Cheap compared to MP.
¢ Multi machine control is possible simultaneously.
Examples 8051 (ATMEL), PIC (Microchip), Motorola (Motorola), ARM Processor.
3.1.4 APPLICATIONS:
¢ Cell phones.
¢ Computers.
¢ Robots.
¢ Interfacing to two pc™s.
3.2 PIC MICROCONTROLLER 16F877A
3.2.1 INTRODUCTION TO PIC MICROCONTROLLER 16F877A
The PIC 16f877A microcontroller is a 40-pin IC. The first pin of the controller is MCLR pin and the 5V dc supply is given to this pin through 10KO resistor. This supply is also given to 11th pin directly. The 12th pin of the controller is grounded. A tank circuit consists of a 4 MHZ crystal oscillator and two 22pf capacitors is connected to 13th and 14th pins of the PIC.
3.2.2 FEATURES OF PIC MICROCONTROLLER 16F877A
¢ Operating frequency: DC-20Mhz.
¢ Flash program memory (14 bit words):8K
¢ Data memory (in bytes): 368
¢ EEPROM Data memory (in bytes):256
¢ Interrupts: 15
¢ I/o ports: A, B, C, D, E
¢ Timers: 3
¢ Analog comparators: 2
¢ Instructions: 35
3.2.3 PIN DIAGRAM OF PIC 16 F874A/877A

FIG 3.1 PIN DIAGRAM OF PIC 16 F874A/877A
3.2.4 FUNCTIONAL BLOCK DIAGRAM OF PIC 16F877A

FIG 3.2 PIN DIAGRAM OF PIC 16F874A/877A
3.3 POWER SUPPLY UNIT
CIRCUIT DIAGRAM

FIG 3.3 POWER SUPPLY UNIT
POWER SUPPLY UNIT COSISTS OF FOLLOWING UNITS
1) Step down transformer
2) Rectifier unit
3) Input filter
4) Regulator unit
v) Output filter
3.3.1 STEP DOWN TRANSFORMER
The Step down Transformer is used to step down the main supply voltage from 230V AC to lower value. This 230 AC voltage cannot be used directly, thus it is stepped down. The Transformer consists of primary and secondary coils. To reduce or step down the voltage, the transformer is designed to contain less number of turns in its secondary core. The output from the secondary coil is also AC waveform. Thus the conversion from AC to DC is essential. This conversion is achieved by using the Rectifier Circuit/Unit.
3.3.2 RECTIFIER UNIT
voltage. The Rectifier circuit is used to convert the AC voltage into its corresponding DC There are Half-Wave, Full-Wave and bridge Rectifiers available for this specific function. The most important and simple device used in Rectifier circuit is the diode. The simple function of the diode is to conduct when forward biased and not to conduct in reverse bias.
The Forward Bias is achieved by connecting the diodeâ„¢s positive with positive of the battery and negative with batteryâ„¢s negative. The efficient circuit used is the Full wave Bridge rectifier circuit. The output voltage of the rectifier is in rippled form, the ripples from the obtained DC voltage are removed using other circuits available. The circuit used for removing the ripples is called Filter circuit.
3.3.3 INPUT FILTER
Capacitors are used as filter. The ripples from the DC voltage are removed and pure DC voltage is obtained. And also these capacitors are used to reduce the harmonics of the input voltage. The primary action performed by capacitor is charging and discharging. It charges in positive half cycle of the AC voltage and it will discharge in negative half cycle. So it allows only AC voltage and does not allow the DC voltage. This filter is fixed before the regulator. Thus the output is free from ripples.
3.3.4 REGULATOR UNIT

FIG 3.4 7805 REGULATOR
Regulator regulates the output voltage to be always constant. The output voltage is maintained irrespective of the fluctuations in the input AC voltage. As and then the AC voltage changes, the DC voltage also changes. Thus to avoid this Regulators are used. Also when the internal resistance of the power supply is greater than 30 ohms, the output gets affected. Thus this can be successfully reduced here. The regulators are mainly classified for low voltage and for high voltage. Further they can also be classified as:
1) Positive regulator
¢ Input pin
¢ Ground pin
¢ Output pin
It regulates the positive voltage.
2) Negative regulator
¢ Ground pin
¢ Input pin
¢ Output pin
It regulates the negative voltage.
3.3.5 OUTPUT FILTER
The Filter circuit is often fixed after the Regulator circuit. Capacitor is most often used as filter. The principle of the capacitor is to charge and discharge. It charges during the positive half cycle of the AC voltage and discharges during the negative half cycle. So it allows only AC voltage and does not allow the DC voltage. This filter is fixed after the Regulator circuit to filter any of the possibly found ripples in the output received finally. Here we used 0.1µF capacitor. The output at this stage is 5V and is given to the Microcontroller.
3.4 RELAY DRIVER
The ULN2001A, ULN2002A, ULN2003 and ULN2004Aare high Voltage, high current Darlington arrays each containing seven open collector Darlington pairs with common emitters. Each channel rated at 500mAand can withstand peak currents of 600mA.Suppressiondiodesare included for inductive load driving and the inputs are pinned opposite the outputs to simplify board layout.
These versatile devices are useful for driving a wide range of loads including solenoids, relays DC motors; LED displays filament lamps, thermal print heads and high power buffers. The ULN2001A/2002A/2003A and 2004A are supplied in 16pin plastic DIP packages with a copper lead frame to reduce thermal resistance.
They are available also in small outline package (SO-16) as ULN2001D/2002D/2003D/2004D.
3.4.1 FEATURES OF DRIVER
¢ SEVENDARLINGTONS PER PACKAGE.
¢ OUTPUT CURRENT 500mA PER DRIVER (600mA PEAK)
¢ OUTPUT VOLTAGE 50V.
¢ INTEGRATED SUPPRESSION DIODES FOR
¢ INDUCTIVE LOADS.
¢ OUTPUTS CAN BE PARALLELED FOR
¢ HIGHERCURRENT.
¢ TTL/CMOS/PMOS/DTLCOMPATIBLE INPUTS.
¢ INPUTS PINNED OPPOSITE OUTPUTS TO
¢ SIMPLIFYLAYOUT
3.4.2 PIN CONNECTION

FIG 3.5 PIN CONNECTIONS OF A RELAY
3.4.3 RELAYS
All relays contain a sensing unit, the electric coil, which is powered by AC or DC current. When the applied current or voltage exceeds a threshold value, the coil activates the armature, which operates either to close the open contacts or to open the closed contacts. When a power is supplied to the coil, it generates a magnetic force that actuates the switch mechanism. The magnetic force is, in effect, relaying the action from one circuit to another. The first circuit is called the control circuit; the second is called the load circuit.
On/Off Control: Example: Air conditioning control, used to limit and control a high power load, such as a compressor Limit Control:
Example: Motor Speed Control, used to disconnect a motor if it runs slower or faster than the desired speed
Logic Operation: Example: Test Equipment, used to connect the instrument to a number of testing points on the device under test.
3.4.4 ELECTROMECHANICAL RELAYS
In our project and implimentation we will be using an electromechanical relay, which will be a 5 pin relay and the working of the relay will be like as. The general-purpose relay is rated by the amount of current its switch contacts can handle. Most versions of the general-purpose relay have one to eight poles and can be single or double throw. These are found in computers, copy machines, and other consumer electronic equipment and appliances.

FIG 3.6 MECHANICAL RELAY
3.4.4.1 INTERNAL OPERATION OF MECHANICAL RELAYS
Standard: Single Side Stable with any of the following three different methods for closing contacts:
1. Flexure Type: The armature actuates the contact spring directly, and the contact is driven into a stationary contact, closing the circuit.
2. Lift-off Type: The moveable piece is energized by the armature, and the contact closes
3. Plunger Type: The lever action caused by the energization of the armature produces a long stroke action. Reed: A Single Side Stable Contact that involves low contact pressure and a simple contact point.
4. Polarized: Can be either a single side stable or dual-winding. A permanent magnet is used to either attract or repel the armature that controls the contact. A definite polarity (+ or -) is required
By the relay coil. The latching option makes a polarized relay dual-winding, meaning it remains in the current state after the coil is de-energized.
3.4.4.5 LOAD TYPES
Load parameters include the maximum permissible voltage and the maximum permissible current. The relay can handle both volts and amps. Both the size of the load and its type are important. There are four types of loads:
1.) Resistive, 2.) Inductive, 3.) AC or DC, and 4.) High or Low Inrush.
3.4.5.1 RESISTIVE LOAD
It is the one that primarily offers resistance to the flow of current. Examples of resistive loads include electric heaters, ranges and ovens, toasters and irons.
3.4.5.2 INDUCTIVE LOADS
It includes power drills, electric mixers, fans, sewing machines and vacuum cleaners. Relays that are going to be subjected to high-inrush inductive loads, such as an AC motor, will often be rated in horsepower, rather than in volts and amps. This rating reflects the amount of power the relay contacts can handle at the moment the device is turned on (or switched).
3.4.5.3 AC OR DC
This affects the contacts circuit of the relay (due to EMF) and the timing sequencing. And may result in performance issues in the switching capacity of the relay for different load types (I.e. resistive, inductive, etc.).




CHAPTER-4
DESCRIBING ABOUT
PROJECTIMPLEMENTATION

4.1 BLOCK DIAGRAM
FIG 4.1 BLOCK DIAGRAM OF DEVELOPMENT OF WEB ENABLED EMBEDDED SYSTEM FOR COMMERCIAL APPLIANCE AND PASSWORD PROTECTED
4.2 DESCRIPTION OF THE BLOCK DIAGRAM
The AC main Block is the power supply which is of single phase 230V ac. This should be given to step down transformer to reduce the 230V ac voltage to low voltage. i.e., to 6V or 12V ac this value depends on the transformer inner winding. The output of the transformer is given to the rectifier circuit. This rectifier converts ac voltage to dc voltage. But the voltage may consist of ripples or harmonics.
To avoid these ripples the output of the rectifier is connected to filter. The filter thus removes the harmonics. This is the exact dc voltage of the given specification. But the controller operates at 5V dc and the relays and driver operates at 12V dc voltage. So we need a regulator to reduce the voltage. 7805 regulator produces 5V dc and 7812 regulator produces 12V dc. Both are positive voltages.
The 7805 regulator produces 5V dc and this voltage is given to PIC micro controller and sensors. The outputs of the sensors are also given to PIC micro controller. Relays are connected to controller through driver. The driver circuit consists of relays and ULN 2003 ICs. The relays are connected to the motor and the two loads.
4.3 CIRCUIT DIAGRAM

FIG 4.2 CIRCUIT DIAGRAM OF DEVELOPMENT OF WEB ENABLED EMBEDDED SYSTEM FOR COMMERCIAL APPLIANCE AND PASSWORD PROTECTED
4.4 POWER SUPPLY DIAGRAM

FIG 4.3 POWER SUPPLY DIAGRAM
4.5 CIRCUIT DESCRIPTION
4.5.1 POWER SUPPLY
Power supply unit consists of Step down transformer, Rectifier, Input filter, Regulator unit, Output filter.
The Step down Transformer is used to step down the main supply voltage from 230V AC to lower value. This 230 AC voltage cannot be used directly, thus it is stepped down. The Transformer consists of primary and secondary coils. To reduce or step down the voltage, the transformer is designed to contain less number of turns in its secondary core. The output from the secondary coil is also AC waveform. Thus the conversion from AC to DC is essential. This conversion is achieved by using the Rectifier Circuit/Unit.
The Rectifier circuit is used to convert the AC voltage into its corresponding DC voltage. There are Half-Wave, Full-Wave and bridge Rectifiers available for this specific function. The most important and simple device used in Rectifier circuit is the diode. The simple function of the diode is to conduct when forward biased and not to conduct in reverse bias.
The Forward Bias is achieved by connecting the diodeâ„¢s positive with positive of the battery and negative with batteryâ„¢s negative. The efficient circuit used is the Full wave Bridge rectifier circuit. The output voltage of the rectifier is in rippled form, the ripples from the obtained DC voltage are removed using other circuits available. The circuit used for removing the ripples is called Filter circuit.
Capacitors are used as filter. The ripples from the DC voltage are removed and pure DC voltage is obtained. And also these capacitors are used to reduce the harmonics of the input voltage. The primary action performed by capacitor is charging and discharging. It charges in positive half cycle of the AC voltage and it will discharge in negative half cycle. Here we used 1000µF capacitor. So it allows only AC voltage and does not allow the DC voltage. This filter is fixed before the regulator. Thus the output is free from ripples.
Regulator regulates the output voltage to be always constant. The output voltage is maintained irrespective of the fluctuations in the input AC voltage. As and then the AC voltage changes, the DC voltage also changes. Thus to avoid this Regulators are used. Also when the internal resistance of the power supply is greater than 30 ohms, the output gets affected. Thus this can be successfully reduced here. The regulators are mainly classified for low voltage and for high voltage. Here we used 7805 positive regulator. It reduces the 6V dc voltage to 5V dc Voltage.
The Filter circuit is often fixed after the Regulator circuit. Capacitor is most often used as filter. The principle of the capacitor is to charge and discharge. It charges during the positive half cycle of the AC voltage and discharges during the negative half cycle. So it allows only AC voltage and does not allow the DC voltage. This filter is fixed after the Regulator circuit to filter any of the possibly found ripples in the output received finally. Here we used 0.1µF capacitor. The output at this stage is 5V and is given to the Microcontroller
In the power supply circuit two regulators are used. 7805 regulator is used to produce positive 5V dc and 7812 regulator produces positive 12V dc voltage. Relays and ULN 2003 drivers operates at 12V dc and microcontroller and sensors are operated at 5V dc voltage. The output of the 7805 regulator is connected to PIC 16f877A microcontroller, sensors and the output of the 7812 regulator is connected to driver ICs and relays.
4.5.2 CONTROLLER CIRCUIT
When the system receives a mail from the person who have provided a certain password, then the PC sends an interrupt to the controller such that the controller can switch ON/OFF the particular device as per the command
The PIC 16f877A microcontroller is a 40-pin IC. The first pin of the controller is MCLR pin and the 5V dc supply is given to this pin through 10KO resistor. This supply is also given to 11th pin directly. The 12th pin of the controller is grounded. A tank circuit consists of a 4 MHZ crystal oscillator and two 22pf capacitors are connected to 13th and 14th pins of the PIC.
The circuit consists one driver IC. IC ULN 2003 is acts as driver. It is a 16- pin IC. This is of NPN transistor type. And this IC is a combination of 7 transistors. At a time we can connect seven loads to each IC. In this project and implimentation we used 4 relays and connected four relays to driver. These relays act as switches also. The 8th pin of driver ICs is grounded and the 9th pin is connected to 12V dc voltage which is from 7812 regulator.
First to fourth pins of driver IC are connected to RB0 to RB3 pins of the controller respectively. Similarly 13th to 16th pins are connected to Relays R4, R3, R2, and R1 respectively. The relays used in this project and implimentation are of Single pole Single throw type.
The Relay Driver Circuit is the main circuit that enables the actual control over the applications. As per the project and implimentation designed, the Relay Driver circuit signals the appliances to be used if the user is valid or authenticated. Here we are using transistor as the relay driver circuit. Relay is connected with the transistor, which generally contains five pins totally. The first two pins are connected with the transistor and contain the magnetic coil wound between them. The rest of the pins are common point, Normally Open (NO) point and Normally Close (NC) point.
Initially common point is in contact with Normally Close point. The magnetic coil also contains an arrangement very similar to that of a hook. When supply is given at the supply point, the magnetic coil of the relay gets energized or activated. Due to this a magnetic field is created that lifts the hook upwards. Thus the arrangement that was initially closed gets opened now. The status of the relay point gets changed (i.e. common point gets connected with normally open point).
The status of the relay is depends upon the conduction of the transistor. The transistor configuration used here is that of common emitter mode. The conduction of the transistor depends on the base voltage of the transistor. The supply to the transistor is given from the regulator of the power supply board. Normally transistor acts as a switch. The switch then gets activated by the Microcontroller.
The output of the relay driver circuit is given to any of the port pins. The Microcontroller is programmed to respond corresponding to the relay signal obtained. Thus the transistor acts as a switch to control the relay and indirectly controls the appliances. The output pins of the first and second relay is connected to the motor. The motor used here is of dc type. The output pin of third relay is connected to the load1 and the fourth relay is connected to the Load2. The No pins of 3rd and 4th relay are connected to the Phase and the Load is connected to the Neutral. The No pins of 1st and 2nd relays are given to the 12V dc supply.
CHAPTER-5
SOFTWARE REQUIREMENTS
SOFTWARE REQUIREMENTS
5.1 SOFTWARE TOOLS
¢ MPLAB
¢ Protel
¢ Propic
¢ HI-Tech PIC C Compiler
5.2 MPLAB INTEGRATION
MPLAB Integrated Development Environment (IDE) is a free, integrated toolset for the development of embedded applications employing Microchip's PIC micro and dsPIC microcontrollers. MPLAB IDE runs as a 32-bit application on MS Windows, is easy to use and includes a host of free software components for fast application development and super-charged debugging. MPLAB IDE also serves as a single, unified graphical user interface for additional Microchip and third party software and hardware development tools. Moving between tools is a snap, and upgrading from the free simulator to MPLAB ICD 2 or the MPLAB ICE emulator is done in a flash because MPLAB IDE has the same user interface for all tools.
Choose MPLAB C18, the highly optimized compiler for the PIC18 series microcontrollers, or try the newest Microchip's language tools compiler, MPLAB C30, targeted at the high performance PIC24 and dsPIC digital signal controllers. Or, use one of the many products from third party language tools vendors. They integrate into MPLAB IDE to function transparently from the MPLAB project and implimentation manager, editor and compiler.
5.3INTRODUCTION TO EMBEDDED ËœCâ„¢:
Ex: Hitec “ c, Keil “ c
HI-TECH Software makes industrial-strength software development tools and C compilers that help software developers write compact, efficient embedded processor code.
For over two decades HI-TECH Software has delivered the industry's most reliable embedded software development tools and compilers for writing efficient and compact code to run on the most popular embedded processors. Used by tens of thousands of customers including General Motors, Whirlpool, Qualcomm, John Deere and many others, HI-TECH's reliable development tools and C compilers, combined with world-class support have helped serious embedded software programmers to create hundreds of breakthrough new solutions.
Whichever embedded processor family you are targeting with your software, whether it is the ARM, PICC or 8051 series, HI-TECH tools and C compilers can help you write better code and bring it to market faster.
HI-TECH PICC is a high-performance C compiler for the Microchip PIC micro 10/12/14/16/17 series of microcontrollers. HI-TECH PICC is an industrial-strength ANSI C compiler - not a subset implementation like some other PIC compilers. The PICC compiler implements full ISO/ANSI C, with the exception of recursion. All data types are supported including 24 and 32 bit IEEE standard floating point. HI-TECH PICC makes full use of specific PIC features and using an intelligent optimizer, can generate high-quality code easily rivaling hand-written assembler. Automatic handling of page and bank selection frees the programmer from the trivial details of assembler code.
5.4 EMBEDDED C COMPILER
¢ ANSI C - full featured and portable
¢ Reliable - mature, field-proven technology
¢ Multiple C optimization levels
¢ An optimizing assembler
¢ Full linker, with overlaying of local variables to minimize RAM usage
¢ Comprehensive C library with all source code provided
¢ Includes support for 24-bit and 32-bit IEEE floating point and 32-bit long data types
¢ Mixed C and assembler programming
¢ Unlimited number of source files
¢ Listings showing generated assembler
¢ Compatible - integrates into the MPLAB IDE, MPLAB ICD and most 3rd-party development tools
¢ Runs on multiple platforms: Windows, Linux, UNIX, Mac OS X, Solaris
5.5 EMBEDDED DEVELOPMENT ENVIRONMENT
This environment allows you to manage all of your PIC project and implimentations. You can compile, assemble and link your embedded application with a single step.
Optionally, the compiler may be run directly from the command line, allowing you to compile, assemble and link using one command. This enables the compiler to be integrated into third party development environments, such as Microchip's MPLAB IDE.
5.6 EMBEDDED SYSTEM TOOLS
5.6.1 ASSEMBLER
An assembler is a computer program for translating assembly language ” essentially, a mnemonic representation of machine language ” into object code. A cross assembler (see cross compiler) produces code for one type of processor, but runs on another. The computational step where an assembler is run is known as assembly time. Translating assembly instruction mnemonics into opcodes, assemblers provide the ability to use symbolic names for memory locations (saving tedious calculations and manually updating addresses when a program is slightly modified), and macro facilities for performing textual substitution ” typically used to encode common short sequences of instructions to run inline instead of in a subroutine. Assemblers are far simpler to write than compilers for high-level languages.
5.6.2 ASSEMBLY LANGUAGE HAS SEVERAL BENEFITS
Speed: Assembly language programs are generally the fastest programs around.
Space: Assembly language programs are often the smallest.
Capability: You can do things in assembly which are difficult or impossible in High level languages.
Knowledge: Your knowledge of assembly language will help you write better programs, even when using High level languages. An example of an assembler we use in our project and implimentation is RAD 51.
5.6.3 SIMULATOR
Simulator is a machine that simulates an environment for the purpose of training or research. We use a UMPS simulator for this purpose in our project and implimentation.
5.6.4 COMPILER
A compiler is a program that reads a program in one language, the source language and translates into an equivalent program in another language, the target language. The translation process should also report the presence of errors in the source program.



There are two parts of compilation. The analysis part breaks up the source program into constant piece and creates an intermediate representation of the source program. The synthesis part constructs the desired target program from the intermediate representation.
5.6.5 COUSINS OF THE COMPILER ARE
1. Preprocessor.
2. Assembler.
3. Loader and Link-editor.
A naive approach to that front end might run the phases serially.
1. Lexical analyzer takes the source program as an input and produces a long string of tokens.
2. Syntax Analyzer takes an out of lexical analyzer and produces a large tree.
Semantic analyzer takes the output of syntax analyzer and produces another tree. Similarly, intermediate code generator takes a tree as an input produced by semantic analyzer and produces intermediate code
5.6.6 PHASES OF COMPILER
The compiler has a number of phases plus symbol table manager and an error handler.

5.7 DESIGN OF EMBEDDED SYSTEM
Like every other system development design cycle embedded system too have a design cycle. The flow of the system will be like as given below. For any design cycle these will be the implementation steps. From the initial state of the project and implimentation to the final fabrication the design considerations will be taken like the software consideration and the hardware components, sensor, input and output. The electronics usually uses either a microprocessor or a microcontroller. Some large or old systems use general-purpose mainframe computers or minicomputers.
USER INTERFACES
User interfaces for embedded systems vary widely, and thus deserve some special comment. User interface is the ultimate aim for an embedded module as to the user to check the output with complete convenience. One standard interface, widely used in embedded systems, uses two buttons (the absolute minimum) to control a menu system (just to be clear, one button should be "next menu entry" the other button should be "select this menu entry").
Another basic trick is to minimize and simplify the type of output. Designs sometimes use a status light for each interface plug, or failure condition, to tell what failed. A cheap variation is to have two light bars with a printed matrix of errors that they select- the user can glue on the labels for the language that he speaks. For example, most small computer printers use lights labeled with stick-on labels that can be printed in any language. In some markets, these are delivered with several sets of labels, so customers can pick the most comfortable language.
In many organizations, one person approves the user interface. Often this is a customer, the major distributor or someone directly responsible for selling the system.
PLATFORM
There are many different CPU architectures used in embedded designs such as ARM, MIPS, Coldfire/68k, PowerPC, X86, PIC, 8051, Atmel AVR, H8, SH, V850, FR-V, M32R etc.
This in contrast to the desktop computer market, which as of this writing (2003) is limited to just a few competing architectures, mainly the Intel/AMD x86, and the Apple/Motorola/IBM PowerPC, used in the Apple Macintosh. With the growing acceptance of Java in this field, there is a tendency to even further eliminate the dependency on specific CPU/hardware (and OS) requirements.
Standard PC/104 is a typical base for small, low-volume embedded and ruggedized system design. These often use DOS, Linux or an embedded real-time operating system such as QNX or Inferno.
A common configuration for very-high-volume embedded systems is the system on a chip, an application-specific integrated circuit, for which the CPU was purchased as intellectual property to add to the IC's design. A related common scheme is to use a field-programmable gate array, and program it with all the logic, including the CPU. Most modern FPGAs are designed for this purpose.
TOOLS
Like typical computer programmers, embedded system designers use compilers, assemblers, and debuggers to develop embedded system software. However, they also use a few tools that are unfamiliar to most programmers.
Software tools can come from several sources:
¢ Software companies that specialize in the embedded market.
¢ Ported from the GNU software development tools.
Sometimes, development tools for a personal computer can be used if the embedded processor is a close relative to a common PC processor. Embedded system designers also use a few software tools rarely used by typical computer programmers.
One common tool is an "in-circuit emulator" (ICE) or, in more modern designs, an embedded debugger. This debugging tool is the fundamental trick used to develop embedded code. It replaces or plugs into the microprocessor, and provides facilities to quickly load and debug experimental code in the system. A small pod usually provides the special electronics to plug into the system. Often a personal computer with special software attaches to the pod to provide the debugging interface.
Another common tool is a utility program (often home-grown) to add a checksum or CRC to a program, so it can check its program data before executing it.
An embedded programmer that develops software for digital signal processing often has a math workbench such as MathCAD or Mathematical to simulate the mathematics.
Less common are utility programs to turn data files into code, so one can include any kind of data in a program. A few project and implimentations use Synchronous programming languages for extra reliability or digital signal processing.
DEBUGGING
Debugging is usually performed with an in-circuit emulator, or some type of debugger that can interrupt the microcontroller's internal microcode. The microcode interrupt lets the debugger operate in hardware in which only the CPU works. The CPU-based debugger can be used to test and debug the electronics of the computer from the viewpoint of the CPU. This feature was pioneered on the PDP-11.
As the complexity of embedded systems grows, higher level tools and operating systems are migrating into machinery where it makes sense. For example, cell phones, personal digital assistants and other consumer computers often need significant software that is purchased or provided by a person other than the manufacturer of the electronics. In these systems, an open programming environment such as Linux, OSGi or Embedded Java is required so that the third-party software provider can sell to a large market.
OPERATING SYSTEM
Embedded systems often have no operating system, or a specialized embedded operating system (often a real-time operating system), or the programmer is assigned to port one of these to the new system.
BUILT- IN SELF- TEST
Most embedded systems have some degree or amount of built-in self-test.
There are several basic types.
1. Testing the computer.
2. Test of peripherals.
3. Tests of power.
4. Communication tests.
5. Cabling tests.
6. Rigging tests.
7. Consumables test.
8. Operational test.
9. Safety test.
START UP
All embedded systems have start-up code. Usually it disables interrupts, sets up the electronics, tests the computer (RAM, CPU and software), and then starts the application code. Many embedded systems recover from short-term power failures by restarting (without recent self-tests). Restart times under a tenth of a second are common.
Many designers have found a few LEDs useful to indicate errors (they help troubleshooting). A common scheme is to have the electronics turn on all of the LED(s) at reset (thereby proving that power is applied and the LEDs themselves work), whereupon the software changes the LED pattern as the Power-On Self Test executes. After that, the software may blink the LED(s) or set up light patterns during normal operation to indicate program execution progress or errors. This serves to reassure most technicians/engineers and some users. An interesting exception is that on electric power meters and other items on the street, blinking lights are known to attract attention and vandalism.
5.8 COMPONENTS USED
1. Step Down Transformer Sad230/12V) “ 1 No.
2. Diodes Sad1N4007) “ 4 No
3. Capacitors :1000µF “ 1 No, 22pF- 2 Nos
4. Regulators :7812 “ 1 No, 7805 “ 1 No
5. Light Emitting Diodes :LED`s “ 2Nos
6. Driver ICs :ULN 2003 “ 1No
7. PIC microcontroller :16f877A “ 1 No
8. Relays :Single Pole Single Throw Type 4Nos
9. Crystal Oscillator :4MHz “ 1Nos
10. Resistors :330 O “ 2Nos,10 KO- 1 No
:1 KO “ 4os,22 KO “ 2Nos
12. Loads :4 Nos
5.9 FABRICATION DETAILS
The fabrication of one demonstration unit is carried out in the following sequence.
¢ Finalizing the total circuit diagram, listing out the components and sources of procurement.
¢ Procuring the components, testing the components and screening the components.
¢ Making layout, repairing the interconnection diagram as per the circuit diagram.
¢ Assembling the components as per the component layout and circuit diagram and soldering components.
¢ Integrating the total unit, interwiring the unit and final testing the unit.
5.10 APPLICATIONS
¢ Commercial appliance
¢ Home appliance
¢ Factory AC controlling
¢ Factory Light controlling
¢ In college labs
¢ In research institutes
CHAPTER-6
RESULTS

KIT

PIC MICRO CONTROLLER 16F877A

ULN 2003 RELAY DRIVER IC AND RELAYS
CONCLUSION
The System DEVELOPMENT OF WEB ENABLED EMBEDDED SYSTEM FOR COMMERECIAL APPLIANCE AND PASSWORD PROTECTED is developed and tested successfully in the laboratory. The microcontroller connected to PC is able to run the loads when certain signal comes to PC as a mail. Here we connected fan, light, AC and motor as loads. It is also possible to switch ON and OFF all the devices or same devices at a time.
SCOPE OF FUTURE STUDY
This project and implimentation can be extended to factories or the project and implimentation can be changed to work on RF communication instead of using E-Mail or it can also converted to work using with a GSM Modem which enables the system using AT commands.
BIBLIOGRAPHY
BOOKS
[1]¦Myke Predcko, Customizing and programming the pic microcontroller
3rd edition The MC Graw-Hill companie
[2]¦W.Chandler Blud, Complete guide to pic microcontroller e-book
[3]¦Kirk Zurell, programming for embedded systems CMP Media,inc.
[4]¦Stan Giblisco Teach yourself electronics and electricity 3rd edition
The MC Graw-Hill companie
[5]¦Jonathan w.Valvano(2000) Embedded Microcomputer system Brooks/Cole
[6]¦John Peatman Embedded PIC microcontroller prentice Hall Professional Technical Reference

WEB SITIES:
Microchips.com
mikroelektronika.co.yu/english/product/books/PICbook/0_Uvod.htm
APPENDIX-A
CODING: DEV_1_ON/OFF
DEV_2_ON/OFF
DEV_3_ON/OFF
DEV_4_ON/OFF
INSTALLING CODING INTO PIC MICROCONTROLLER
1. Write the program in MPLAB IDE.
2. Save the file as *.c. and compile it.
3. After successful compilation of the coding close the MPLAB IDE.
4. Fix the Controller IC into PIC Flash kit.
5. Then click on Micro controller Micro Systems PIC Flash Software Icon on the desktop.
6. It displays on dialog box. Then select open and select the program which we already saved as *.c.
7. Then it asks the Confirmation that The IC is empty, select ok.
8. Then it asks Fuses Settings, select YES
9. Then it displays Fuses Settings Dialog Box.
10. In that put WDT -- > Disabled, WRT-- > Enabled, Oscillator-- > XT then click on OK.
11. Then it displays the Program successfully installed into PIC.
12. Then Remove the IC from the PIC Flash and it is ready for used into the project and implimentation or circuit operation.
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