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Touch screen and Zigbee based wireless communication assistant for Dumb/Illiterates in Airlines

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CHAPTER 1 INTRODUCTION1.1 IntroductionThe main aim of our project is to construct a user friendly communication system for illiterate/dumb people traveling by Airlines. In our project we are building a device that helps them in expressing their needs with other language people (Air hostess) i.e., request them if they need anything in the flight like coffee, tea, drinks etc.

In this project we use Touch screen Technology to make it easy even to illiterates as it is also included with images, which indicates the needs. This even reduces the difficulty to airhostess in receiving the customers with different languages. Here for wireless communication purpose we use Zigbee technology.

Zigbee is a wireless technology developed as an open global standard to address the unique needs of low-cost, low-power, wireless sensor networks. Zigbee is built around the IEEE 802.15.4 wireless protocol. As Zigbee is the upcoming technology in wireless field, we had tried to demonstrate its way of functionality and various aspects like kinds, advantages and disadvantages using a small application of controlling the any kind of electronic devices and machines. The Zigbee technology is broadly adopted for bulk and fast data transmission over a dedicated channel.

This project consists of Zigbee based system that transmits the wireless signals according to the input given by the user, using touch screen and GLCD through images. At the receiver (airhostess) end the information will be displayed on GLCD in English language. Here when the user sends his need through a gentle touch on the images displayed on touch screen GLCD, then micro controller transmits that information through Zigbee transmitter. The information received by the Zigbee receiver will be displayed on GLCD.

NALLA MALLA REDDY ENGINEERING COLLEGE

ELECTRONICS AND COMMUNICATION ENGINEERING


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1.2 Project OverviewAn embedded system is a combination of software and hardware to perform a dedicated task. Some of the main devices used in embedded products are Microprocessors and Microcontrollers. Microprocessors are commonly referred to as general purpose processors as they simply accept the inputs, process it and give the output. In contrast, a microcontroller not only accepts the data as inputs but also manipulates it, interfaces the data with various devices, controls the data and thus finally gives the result. The project Touch screen and Zigbee based wireless communication assistant for Dumb/Illiterates in Airlines and also by using 18F452 and 16F73 Microcontroller is an exclusive project that is used to construct a user friendly multi-language communication system for illiterate/dumb people traveling by Airlines.

1.3 Thesis OverviewThe thesis explains the implementation of Touch screen and Zigbee based wireless communication assistant for Dumb/Illiterates in Airlines using 18F452 and 16F73 microcontrollers. The organization of the thesis is explained here with:

Chapter 2 Presents the transmitter block diagram. It explains about hardware description of each block of transmitter section.

Chapter 3 Presents the receiver block diagram. It explains about hardware description of each block of receiver section.




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Chapter 4 Presents the software description. It explains the step by step procedure for compiling, simulation and dumping. Chapter 5 Presents the project description along with schematic diagram of transmitter and receiver. Chapter 6 Presents the advantages, disadvantages and applications of the project. Chapter 7 Presents the results and kit overview of the project. Conclusion and future scope of the project.




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CHAPTER 2 TRANSMITTER SECTIONTransmitter section consists of PIC microcontroller (18F452), zigbee module, regulated power supply, touch screen, GLCD and RS232 for interfacing microcontroller and zigbee module.

2.1 Block diagram of transmitter:

Fig 2.1 Block diagram of transmitter section




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Description of each block 2.2 Regulated power supplyPower supply is the major concern for every electronic device. Since the controller and other devices used are low power devices there is a need to step down the voltage and as well as rectify the output to convert the output to a constant dc. Transformer is a device used to increment or decrement the input voltage given as per the requirement. The transformers are classified into two types depending upon their functionality. Step up transformer Step down transformer

In our project we are using a step down transformer for stepping down the house hold ac power supply i.e. the 230-240v power supply to 12V.We use a 12V step down transformer. The output of the transformer is an ac and should be rectified to a constant dc for this it is necessary to feed the output of the transformer to a rectifier. 2.2.1 RECTIFIER The rectifier is employed to convert the ac to a constant dc. There are many rectifiers available in the market some of them are: Half wave rectifier Full wave rectifier Bridge rectifier




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The rectification is done by using one or more diodes connected in series or parallel. If only one diode is used then only first half cycle is rectified and it is termed as half wave rectification and the rectifier used is termed as half wave rectifier. If two diodes are employed in parallel then both positive and negative half cycles are rectified and this is full wave rectification and the rectifier is termed as Full wave rectifier. If the diodes are arranged in the form of bridge then it is termed as Bridge rectifier, it acts as a full wave rectifier.

2.2.2 Voltage regulator These regulators are available in the market in the form of integrated chips (I.Cs) The voltage regulator is used for the voltage regulation purpose. We use IC 7805 voltage regulator. The IC number has a specific significance. The number 78 represents the series while 05 represent the output voltage generated by the IC. 2.2.3 Light emitting diode We employ a light emitting diode for testing the functionality of the power supply circuit. Here we use a 3V LED which is connected in series with the power supply circuit it verifies the functioning of the power supply LEDs are also employed in other areas for many purposes. The following are the advantages of using LEDs. It helps us while troubleshooting the device i.e. when the device is malfunctioning it would be easy to detect where the actual problem a raised.NALLA MALLA REDDY ENGINEERING COLLEGE ELECTRONICS AND COMMUNICATION ENGINEERING


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LED employed with microcontroller verifies whether data is being transmitted.

It verifies the functionality of the power supply.

BLOCK DIAGRAM OF POWER SUPPLY

Fig 2.2 Block diagram of a power supply




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CIRCUIT DIAGRAM

Fig 2.3 Circuit diagram of power supply

2.3 Microcontroller PIC18F4522.3.1 Description of PIC18F452 microcontroller The pin configuration of the PIC18F452 microcontroller (DIP package). This is a 40-pin microcontroller housed in a DIL package, with a pin configuration similar to the popular PIC16F877. PIC18F2X2 microcontrollers are 28-pin devices, while PIC18F4X2

microcontrollers are 40-pin devices. The architectures of the two groups are almost identical except that the larger devices have more input-output ports and more A/D converter channels. In this section we shall be looking at the architecture of the PIC18F452 microcontroller in detail. The architectures of other standard PIC18F-series microcontrollers are similar, and the knowledge gained in this section should be enough to understand the operation of other PIC18F-series microcontrollers.




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Program memory addresses consist of 21 bits, capable of accessing 2Mbytes of program memory locations. The PIC18F452 has only 32Kbytes of program memory, which requires only 15 bits. The remaining 6 address bits are redundant and not used. A table pointer provides access to tables and to the data stored in program memory. The program memory contains a 31-level stack which is normally used to store the interrupt and subroutine return addresses. The data memory bus is 12 bits wide, capable of accessing 4Kbytes of data memory locations. The data memory also consists of special function registers (SFR) and general purpose registers, all these are organized in banks. The PIC18F452 consists timers/counters, capture/compare/PWM registers, USART, A/D converter, and EEPROM data memory. The PIC18F452 consists of: 1. 2. 3. 4. 5. 4 timers/counters 2 capture/compare/PWM modules 2 serial communication modules 8 10-bit A/D converter channels 256 bytes EEPROM

2.3.2 The basic features of PIC18F-series microcontrollers are 77 instructions PIC16 source code compatible Program memory addressing up to 2Mbytes Data memory addressing up to 4Kbyteswpress.com DC to 40MHz operation 8X8 hardware multiplier Interrupt priority levels 16-bit-wide instructions, 8-bit-wide data path




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Up to two 8-bit timers/counters Up to three 16-bit timers/counters Up to four external interrupts High current (25mA) sink/source capability Up to five capture/compare/PWM modules Master synchronous serial port module (SPI and I2C modes) Up to two USART modules Parallel slave port (PSP) Fast 10-bit analog-to-digital converter Programmable low-voltage detection (LVD) module Power-on reset (POR), power-up timer (PWRT), and oscillator start-up timer (OST) Watchdog timer (WDT) with on-chip RC oscillator In-circuit programming Most devices in the PIC18F family are source compatible with each other. The

architectures of most of microcontrollers in the PIC18F family are similar.




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2.3.3 PIN Diagram of PIC18F452

Fig 2.4 Pin diagram of the PIC18F452 microcontroller. Parallel I/O Ports The parallel ports in PIC18F microcontrollers are very similar to those of the PIC16 series. The number of I/O ports and port pins varies depending on which PIC18F microcontroller is used, but all of them have at least PORTA and PORTB. The pins of a port are labeled as RPn, where P is the port letter and n is the port bit number. For example, PORTA pins are labeled RA0 to RA7, PORTB pins are labeled RB0 to RB7, and so on.NALLA MALLA REDDY ENGINEERING COLLEGE ELECTRONICS AND COMMUNICATION ENGINEERING


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The first three operations are the same in the PIC16 and the PIC18F series. In some applications we may want to send a value to the port and then read back the value just sent. The PIC16 series has a weakness in the port design such that the value read from a port may be different from the value just written to it. This is because the reading the actual port bit pin value and this value can be changed by external devices connected to the port pin. In the PIC18F series, a latch register (e.g., LATA for PORTA) is introduced to the I/O ports to hold the actual value sent to a port pin. Reading from the port reads the latched value, which is not affected by any external device. In this section we shall be looking at the general structure of I/O ports. PORTA in the PIC18F452 microcontroller PORTA is 7 bits wide and port pins are shared with other functions. There are three registers associated with PORTA: 1. 2. 3. Port data registerPORTA Port direction registerTRISA Port latch registerLATA

PORTA PORTA is the name of the port data register. The TRISA register defines the direction of PORTA pins, where logic 1 in a bit position defines the pin as an input pin, and a 0 in a bit position defines it as an output pin. LATA is the output latch registers which shares the same data latch as PORTA. Writing to one is equivalent to writing to the other. But reading from LATA activates the buffer at the top, and the value held in the PORTA/LATA data latch is transferred to the data bus independent of the state of the actual output pin of the microcontroller. Bits 0 through 3 and 5 of PORTA are also used as analog inputs. After reset, these pins are programmed as analog inputs and RA4 and RA6 are configured as digital inputs. To program the analog inputs as digital I/O, the ADCON1 register (A/D register) must be programmed accordingly. Writing 7 to ADCON1 configures all PORTA pins as digital I/O. The RA4 pin is multiplexed with the




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Timer 0 clock input (T0CKI). This is a Schmitt trigger input and an open drain output. RA6 can be used as a general purpose I/O pin, as the OSC2 clock input, or as a clock output providing FOSC/4 clock pulses. PORTB In PIC18F452 microcontroller PORTB is an 8-bit bidirectional port shared with interrupt pins and serial device programming pins. PORTB is controlled by three registers: 1. 2. 3. Port data registerPORTB Port direction registerTRISB Port latch registerLATB The general operation of PORTB is similar to that of PORTA. Each port pin has a weak internal pull-up which can be enabled by clearing bit RBPU of register INTCON2. These pull-ups are disabled on a power-on reset and when the port pin is configured as an output. On a power-on reset, PORTB pins are configured as digital inputs. Internal pullups allow input devices such as switches to be connected to PORTB pins without the use of external pull-up resistors. This saves costs because the component count and wiring requirements are reduced. www.newnespress.cwww.newnespress.com PortB pins RB4RB7 can be used as interrupt-on-change inputs, whereby a change on any of pins 4 through 7 causes an interrupt flag to be set. The interrupt enable and flag bits RBIE and RBIF are in register INTCON. PORTC, PORTD, PORTE, and In addition to PORTA and PORTB, the PIC18F452 has 8-bit bidirectional ports PORTC and PORTD, and 3-bit PORTE. Each port has its own data register (e.g., PORTC), data PIC18F452 PORTB RB4RB7 pins.




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PORTC and PORT D In the PIC18F452 microcontroller PORTC is multiplexed with several peripheral functions. On a power-on reset, PORTC pins are configured as digital inputs. In the PIC18F452 microcontroller, PORTD has Schmitt trigger input buffers. On a power-on reset, PORTD is configured as digital input. PORTD can be configured as an 8-bit parallel slave port (i.e., a microprocessor port) by setting bit 4 of the TRISE register. PORTE In the PIC18F452 microcontroller, PORTE is only 3 bits wide. PortE pins are shared with analog inputs and with parallel slave port read/write control bits. On a poweron reset, PORTE pins are configured as analog inputs and register ADCON1 must be programmed to change these pins to digital I/O. The PIC18F452 microcontroller has four programmable timers which can be used in many tasks, such as generating timing signals, causing interrupts to be generated at specific time intervals, measuring frequency and time intervals, and so on. This section introduces the timers available in the PIC18F452 microcontroller. 2.3.4 Features of PIC 18F452 Power Supply PIC18F452 can operate with a supply voltage of 4.2V to 5.5V at the full speed of 40MHz. The lower power version, PIC18F452, can operate from 2.0 to 5.5 volts. At lower voltages the maximum clock frequency is 4MHz, which rises to 40MHz at 4.2V. The RAM data retention voltage is specified as 1.5V and will be lost if the power supply voltage is lowered below this value. In practice, most microcontroller-based systems are operated with a single 5V supply derived from a suitable voltage regulator.




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Reset The reset action puts the microcontroller into a known state. Resetting a PIC18F microcontroller starts execution of the program from address 0000H of the program memory. The microcontroller can be reset during one of the following operations: 1. 2. 3. 4. 5. Power-on reset (POR) MCLR reset Watchdog timer (WDT) reset Brown-out reset (BOR) Reset instruction

Power-on Reset The power-on reset is generated automatically when power supply voltage is applied to the chip. The MCLR pin should be tied to the supply voltage directly or, preferably, through a 10K resistor. For applications where the rise time of the voltage is slow, it is recommended to use a diode, a capacitor, and a series resistor. In some applications the microcontroller may have to be reset externally by pressing a button. Normally the MCLR input is at logic1.When the RESET button is pressed, this pin goes to logic 0 and resets the microcontroller. The Clock Sources The PIC18F452 microcontroller can be operated from an external crystal or ceramic resonator connected to the microcontrollers OSC1 and OSC2 pins. In addition, an external resistor and capacitor, an external clock source and in some models internal oscillators can be used to provide clock pulses to the microcontroller.




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Watchdog Timer In PIC18F-series microcontrollers family members the watchdog timer (WDT) is a free running on-chip RC-based oscillator and does not require any external components. When the WDT times out, a device RESET is generated. If the device is in SLEEP mode, the WDT time-out will wake it up and continue with normal operation. The watchdog is enabled / disabled by bit SWDTEN of register WDTCON. Setting SWDTEN = 1 enables the WDT, and clearing this bit turns off the WDT. On the PIC18F452 microcontroller an 8-bit postscaler is used to multiply the basic time-out period from 1 to 128 in powers of 2. This postscaler is controlled from configuration register CONFIG2H. The typical basic WDT time-out period is 18ms for a postscaler value of 1. The PIC18F452 has five parallel ports named PORTA, PORTB, PORTC, PORTD, and PORTE. Most port pins have multiple functions. For example, PORTA pins can be used as parallel inputs-outputs or analog inputs. PORTB pins can be used as parallel inputs-outputs or as interrupt inputs. Timers The PIC18F452 microcontroller has four programmable timers which can be used in many tasks, such as generating timing signals, causing interrupts to be generated at specific time intervals, measuring frequency and time intervals, and so on. Timer 0: Timer 0 is similar to the PIC16 series. Timer 0, except that it can operate either in 8-bit or in 16-bit mode. Timer 0 has the following basic features: 8-bit or 16-bit operation 8-bit programmable prescaler External or internal clock source Interrupt generation on overflow




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Timer 0 control register is T0CON, shown in Figure 2.24. The lower 6 bits of this register have similar functions to the PIC16-series OPTION register. The top two bits are used to select the 8-bit or 16-bit mode of operation and to enable/disable the timer. Timer 1: PIC18F452 Timer 1 is a 16-bit timer controlled by register T1CON Timer 2: Timer 2 is an 8-bit timer with the following features: 8-bit timer (TMR2) 8-bit period register (PR2) Programmable prescaler Programmable postscaler Interrupt when TM2 matches PR2

Timer 3: The structure and operation of Timer 3 is the same as for Timer 1, having registers TMR3H and TMR3L. Capture/Compare/PWM Modules (CCP) The PIC18F452 microcontroller has two capture/compare/PWM (CCP) modules, and they work with Timers 1, 2, and 3 to provide capture, compare, and pulse width modulation (PWM) operations. Each module has two 8-bit registers. Analog-to-Digital Converter (A/D) Module An analog-to-digital converter (A/D) is another important peripheral component of a microcontroller. The A/D converts an analog input voltage into a digital number so it can be processed by a microcontroller or any other digital system. There are many analog-to-digital converter chips available on the market, and an embedded systems




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designer should understand the characteristics of such chips so they can be used efficiently. Interrupts The PIC18F452 microcontroller has both core and peripheral interrupt sources. The core interrupt sources are: External edge-triggered interrupt on INT0, INT1, and INT2 pins. PORTB pins change interrupts (any one of the RB4RB7 pins changing state) Timer 0 overflow interrupt

The peripheral interrupt sources are: Parallel slave port read/write interrupt A/D conversion complete interrupt USART receive interrupt USART transmit interrupt Synchronous serial port interrupt CCP1 interrupt TMR1 overflow interrupt TMR2 overflow interrupt Comparator interrupt

2.3.5 Memory Organization Program Memory Organization All PIC18F devices have a 21-bit program counter and hence are capable of addressing 2Mbytes of memory space. User memory space on the PIC18F452 microcontroller is 00000H to 7FFFH. Accessing a nonexistent memory location (8000H




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to 1FFFFFH) will cause a read of all 0s. The reset vector, where the program starts after a reset, is at address 0000. Addresses 0008H and 0018H are reserved for the vectors of high-priority and low-priority interrupts respectively, and interrupt service routines must be written to start at one of these locations. The PIC18F microcontroller has a 31-entry stack that is used to hold the return addresses for subroutine calls and interrupt processing. The stack is not part of the program or the data memory space. The stack is controlled by a 5-bit stack pointer which is initialized to 00000 after a reset. During a subroutine call (or interrupt) the stack pointer is first incremented, and the memory location it points to is written with the contents of the program counter. During the return from a subroutine call (or interrupt), the memory location the stack pointer has pointed to is decremented. The projects in this book are based on using the C language. Since subroutine and interrupt call/return operations are handled automatically by the C language compiler, their operation is not described here in more detail. Program memory is addressed in bytes, and instructions are stored as two bytes or four bytes in program memory. The least significant byte of an instruction word is always stored in an even address of the program memory. An instruction cycle consists of four cycles: A fetch cycle begins with the program counter incrementing in Q1. In the execution cycle, the fetched instruction is latched into the instruction register in cycle Q1. This instruction is decoded and executed during cycles Q2, Q3, and Q4. A data memory location is read during the Q2 cycle and written during the Q4 cycle. Data Memory Organization The data memory address bus is 12 bits with the capability to address up to 4Mbytes. The memory in general consists of sixteen banks, each of 256 bytes, where only 6 banks are used. The PIC18F452 has 1536 bytes of data memory (6 banks of 256




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bytes each) occupying the lower end of the data memory. Bank switching happens automatically when a high-level language compiler is used, and thus the user need not worry about selecting memory banks during programming. The special function register (SFR) occupies the upper half of the top memory bank. SFR contains registers which control operations such as peripheral devices, timers/ counters, A/D converter, interrupts, and USART.

2.4 COMMUNICATION INTERFACE2.4.1 RS-232 In telecommunications, RS-232 (sometimes also referred to as EIA RS-232C (EIA: Electronic Industries Association) is a standard for serial binary data interconnection between a DTE (Data terminal equipment) and a DCE (Data communication equipment). It is commonly used in computer serial ports. RS-232-C defines:

Electrical signal characteristics such as voltage levels, signaling rate, timing and slew-rate of signals, voltage withstand level, short-circuit behavior, maximum stray capacitance and cable length.

Interface mechanical characteristics, pluggable connectors and pin identification. Functions of each circuit in the interface connector. Standard subsets of interface circuits for selected telecomm applications. The standard does not define elements such as character encoding (for

example, ASCII, Baudot or EBCDIC), the framing of characters in the data stream (bits per character, start/stop bits, parity), bit rates for transmission, although the standard says it is intended for bit rates less than 20,000 bits per second. Some types of equipment exceed this speed while still using RS-232 compatible signal levels. The original letters "RS" stands for "Recommended Standard".NALLA MALLA REDDY ENGINEERING COLLEGE ELECTRONICS AND COMMUNICATION ENGINEERING


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2.4.2 Standard details Voltage levelsThe RS-232 standard defines the voltage levels that correspond to logical one and logical zero levels. Signals are plus or minus 3 to 15 volts. The range near zero volts is not a valid RS-232 level, logic one is defined as a negative voltage, the signal condition is called marking, and has the functional significance of OFF. Logic zero is positive, the signal condition is spacing, and has the function ON. The standard specifies a maximum open-circuit voltage of 25 volts. Circuits driving an RS-232-compatible interface must be able to withstand indefinite short circuit to ground or to any voltage level up to 25 volts. The slew rate, or how fast the signal changes between levels, is also controlled.

2.5 TOUCH SCREENTouch screens are popular in heavy industry and in other situations, such as museum displays or room automation, where keyboard and mouse systems do not allow a satisfactory, intuitive, rapid, or accurate interaction by the user with the display's content. 2.5.1 Technologies of touch screen There are a number of types of touch screen technology as described below 1. Resistive A resistive touch screen panel is composed of several layers, the most important of which are two thin, metallic, electrically conductive layers separated by a narrow gap. When an object, such as a finger, presses down on a point on the panel's outer surface the two metallic layers become connected at that point: the panelNALLA MALLA REDDY ENGINEERING COLLEGE ELECTRONICS AND COMMUNICATION ENGINEERING


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then behaves as a pair of voltage dividers with connected outputs. This causes a change in the electrical current which is registered as a touch event and sent to the controller for processing. 2. Surface acoustic wave Surface acoustic wave (SAW) sumit technology uses ultrasonic waves that pass over the touch screen panel. When the panel is touched, a portion of the wave is absorbed. This change in the ultrasonic waves registers the position of the touch event and sends this information to the controller for processing. Surface wave touch screen panels can be damaged by outside elements. Contaminants on the surface can also interfere with the functionality of the touch screen. 3. Capacitive A capacitive touch screen panel consists of an insulator such as glass, coated with a transparent conductor such as indium tin oxide (ITO). As the human body is also a conductor, touching the surface of the screen results in a distortion of the body's electrostatic field, measurable as a change in capacitance. Different technologies may be used to determine the location of the touch. The location can be passed to a computer running a software application which will calculate how the user's touch relates to the computer software. 2.5.2 Construction There are several principal ways to build a touch screen. The key goals are to recognize one or more fingers touching a display, to interpret the command that this represents, and to communicate the command to the appropriate application. In the most popular techniques, the capacitive or resistive approach, there are typically four layers:




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1. Top polyester layer coated with a transparent metallic conductive coating on the bottom. 2. Adhesive spacer 3. Glass layer coated with a transparent metallic conductive coating on the top. 4. Adhesive layer on the backside of the glass for mounting. When a user touches the surface, the system records the change in the electrical current that flows through the display. Dispersive-signal technology which 3M created in 2002, measures the piezoelectric effect (the voltage generated when mechanical force is applied to a material) that occurs chemically when a strengthened glass substrate is touched. There are two infrared-based approaches. In one, an array of sensors detects a finger touching or almost touching the display, thereby interrupting light beams projected over the screen. In the other, bottom-mounted infrared cameras record screen touches. In each case, the system determines the intended command based on the controls showing on the screen at the time and the location of the touch. Resistive Touch screen Technology Resistive LCD touch screen monitors rely on a touch overlay, which is composed of a flexible top layer and a rigid bottom layer separated by insulating dots, attached to a touch screen controller. The inside surface of each of the two layers is coated with a transparent metal oxide coating (ITO) that facilitates a gradient across each layer when voltage is applied. Pressing the flexible top sheet creates electrical contact between the resistive layers, producing a switch closing in the circuit. The control electronics alternate voltage between the layers and pass the resulting X and Y touch coordinates to the touch screen controller. The touch screen controller data is then passed on to the computer operating system for processing.




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Resistive touch screens are composed of two flexible sheets coated with a resistive material and separated by an air gap or microdots. When contact is made to the surface of the touch screen, the two sheets are pressed together, registering the precise location of the touch. Because the touch screen senses input from contact with nearly any object (finger, stylus/pen, palm) resistive touch screens are a type of "passive" technology.

Working of Resistive Touch screens

Fig 2.5 Diagram of touch screen working 1. Polyester Film 2. Upper Resistive circuit Layer 3. Conductive ITO (Transparent Metal Coating). 4. Lower Resistive Circuit Layer 5. Insulating Dots




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6. Glass/Acrylic Substrate 7. Touching the overlay surface causes the (2) Upper Resistive Circuit Layer to contact the (4) Lower Resistive Circuit Layer, producing a circuit switch from the activated area. 8. The touch screen controller gets the alternating voltages between the (7) two circuit layers and converts them into the digital X and Y coordinates of the activated area.

Because of its versatility and cost-effectiveness, resistive touch screen technology is the touch technology of choice for many markets and applications. Resistive touch screens are used in food service, retail point-of-sale (POS), medical monitoring devices, industrial process control and instrumentation, portable and handheld products. Resistive touch screen technology possesses many advantages over other alternative touch screen technologies (acoustic wave, capacitive, Near Field imaging, and infrared). Highly durable, resistive touch screens are less susceptible to contaminants that easily infect acoustic wave touch screens. In addition, resistive touch screens are less sensitive to the effects of severe scratches that would incapacitate capacitive touch screens. For industrial applications, resistive touch screens are more cost-effective solutions than Near Field Imaging touch screens. A four-wire resistive touch screen panel consists of two flexible layers uniformly coated with a transparent resistive material and separated by an air gap. Electrodes placed along the edges of the layers provide a means for exciting and monitoring the touch screen.




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Fig 2.6 Block Diagram of Touch Screen Interface

Fig 2.7 Touch screen microcontroller interface through touch screen controller

When a position is measured on a 4-wire touch screen, voltage is applied across the screen in the Y direction; and a touch presses the layers together, where a voltage can be read from one of the X electrodes. The contact made as a result of the touch creates a voltage divider at that point, so the Y coordinate can be determined; the process thenNALLA MALLA REDDY ENGINEERING COLLEGE ELECTRONICS AND COMMUNICATION ENGINEERING


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repeats with the X direction being driven, and a reading is taken from one of the Y electrodes. A touch-screen controller is simply an ADC that has built-in switches to control which electrodes are driven and which electrodes are used as the input to the ADC. An Analog Devices AD7843 scans the X and Y axes and determines the unique voltage drop for each axis. The four electrodes for scanning are labeled X+, X-, Y+, and Y-. These electrodes are connected to the AD7843 touch screen controller and the touch sensor is scanned and the analog voltages read. The four touch electrodes are connected to the inputs X+, X-, Y+, and Y- of the AD7843. A selected axis (X or Y) pair of electrodes is energized with a static voltage and the voltage of the positive electrode of the other pair in the 4 wire touch panel is measured. The sensed voltage is measured and converted to either an 8 bit or 12 bit resolution. A digital word representing the voltage at the contacting point on the touch panel is created and sent out via a high speed SPI serial interface.

2.5.3 Comparisons of all Resistive Touch Technologies: (4-, 5-, 6-, 7-, and 8-Wire) Resistive touch screens are used in more applications than any other touch technologyfor example, PDAs, point-of-sale, industrial, medical, and office automation, as well as consumer electronics. All variations of resistive touch screens have some things in common:




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Fig 2.8 Diagram of finger representation with Touch Screen

They are all constructed similarly in layers-a back layer such as glass with a uniform resistive coating plus a polyester coversheet, with the layers separated by tiny insulating dots. When the screen is touched, it pushes the conductive coating on the coversheet against the coating on the glass, making electrical contact. The voltages produced are the analog representation of the position touched. An electronic controller converts these voltages into digital X and Y coordinates which are then transmitted to the host computer.

Because resistive touch screens are force activated, all kinds of touch input devices can activate the screen, including fingers, fingernails, styluses, gloved hands, and credit cards.

All have similar optical properties, resistance to chemicals and abuse. Both the touch screen and its electronics are simple to integrate into imbedded systems, thereby providing one of the most practical and cost-effective touch screen solutions.




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Fig 2.9 Diagram of four wires resistive 2.5.4 Four-Wire Resistive Four-wire resistive technology is the simplest to understand and manufacture. It uses both the upper and lower layers in the touch screen sandwiched to determine the X and Y coordinates. Typically constructed with uniform resistive coatings of Indium Tin Oxide (ITO) on the inner sides of the layers and silver buss bars along the edges, the combination sets up lines of equal potential in both X and Y. In the illustration below, the controller first applies 5V to the back layer. Upon touch, it probes the analog voltage with the coversheet, reading 2.5V, which represents a left-right position or X axis. It then flips the process, applying 5V to the coversheet, and probes from the back layer to calculate an up-down position or Y axis. At any time, only three of the four wires are in use (5V, ground, and probe).




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2.5.5 Features

Input Method: Stylus, Finger, Gloved Hand Widest Range in Sizes: 1.4" ~ 21" High Transmission Rate Low Power Consumption Narrow Boarder Design Writing and Signature Capture Capability

Various Constructions Available Film/Glass Film/Strengthened Glass Film/Film/PC Sunlight Readability Available Palm Rejection Model Available

2.5.6 Disadvantages of touch screen

Fig 2.10 Disadvantage of a touch screen




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The primary drawback of four-wire technology is that one coordinate axis (usually the Y axis), uses the outer layer, the flexible coversheet, as a uniform voltage gradient. The constant flexing that occurs on the outer coversheet with use will eventually cause microscopic cracks in the ITO coating, changing its electrical characteristics (resistance), degrading the linearity and accuracy of this axis. Unsurprisingly, four-wire touch screens are not known for their durability. Typically, they test only to about 1 million touches with a finger-far less when activated by a pointed stylus which speeds the degradation process. Some four-wire products even specify 100,000 activations within a rather large, 20 mm x 20 mm area. In the real world of point-of-sale applications, a level of 100,000 activations with hard, pointed styluses (including fingernails, credit cards, ballpoint pens, etc.) is considered normal usage in just a few months' time. Also, accuracy can drift with environmental changes. The polyester coversheet expands and contracts with temperature and humidity changes, thereby causing long-term degradation to the coatings as well as drift in the touch location. While all of these drawbacks can be insignificant in smaller sizes, they become increasingly apparent the larger the touch screen. Therefore, Elo normally recommends four-wire touch screens in applications with a display size of 6.4" or smaller. However, the relative low cost, inherent low power consumption, and common availability of chipset controllers with support from imbedded operating systems, makes Elo AT4 four-wire touch screens ideal for hand-held devices such as PDAs, wearable computers, and many consumer devices. The 4-Wire Resistive Add-on/Internal Touch Screen for less demanding touch applications Great for general use, demos, trade shows, proto-typing, proof of concepts, low cost touch requirement. 4-wire analog resistive touch technology is suitable for applications that require ease of integration, low power consumption, lightweight, portability, cost effectivenessNALLA MALLA REDDY ENGINEERING COLLEGE ELECTRONICS AND COMMUNICATION ENGINEERING


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and compact mechanism. Affordable, durable and versatile, the 4-wire resistive touch screens are primarily used in mobile applications, such as smart phones, PDAs, e-books, web pads, digital cameras, GPS, and other consumer or office electronics.

2.6 GLCD 2.6.1 Graphic LCD 128x64This 128x64 graphic LCD is the latest high quality offering from Crystal Fonts This production unit is much more than just a surplus LCD found on many electronics sites. This CFAX model comes with an EL backlight and a 4-wire analog touch screen. Features

Ultra thin and light TAB construction Wide viewing angles Built-in controller: Samsung KS0713 (data sheet 850K). Great for hand held instruments, cell phones, PDAs, etc. Ultra low power consumption

Dimensions

56.0mm x 42.5mm Module Outline (less tab) 52.0mm x 33.5mm Viewing Area 47.76mm x 30.29mm Active Area 0.35mm x 0.40mm Dot Pitch




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Fig 2.11 128x64 Graphic LCD (SKU: FIT0021) This is a 128x64 liquid crystal display that support Chinese character, English characters and even graphics, very suitable for interactive work.

Specifications

Voltage: 5V With Chinese font Blue backlit Controller: ST7920 Size: 93x70mm

Fig2.12 128x64 Graphic LCD (SKU: FIT0021)NALLA MALLA REDDY ENGINEERING COLLEGE ELECTRONICS AND COMMUNICATION ENGINEERING


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The specifications of GLCD are as follows:

128 horizontal pixel and 64 vertical pixel resolution. Controlled based on KS0108B Parallel 8bit interface On board graphic memory. Available in Green backlight with dark green pixels. Also available in Blue backlight with light blue pixels. LED backlight. 20 PIN linear connection.




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2.6.2 PIN Description Connection with AVR PIN

PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Vss Vcc V0 RS

Name Ground

Function

+5v Supply in Contrast Adjust Instruction/Data Register Select READ/WRITE SELECTION ENABLE SIGNAL DATA IN/OUT DATA IN/OUT DATA IN/OUT DATA IN/OUT DATA IN/OUT DATA IN/OUT DATA IN/OUT DATA IN/OUT Chip Select 1 Chip Select 2 RESET SIGNAL NEGATIVE 10V OUT LED BACKLIGHT LED BACKLIGHT Table 1 Pin description of GLCD PD3 PD6 PB4 PC0 PC1 PC2 PC3 PC4 PC5 PC6 PC7 PB0 PB1 RESET

R/W E DB0 DB1 DB2 DB3 DB4 DB5 DB6 DB7 CS1 CS2 RST VEE LED+ LED-

Salient features of the Interface with Graphical LCD Display are as follows: Programming of additional vacuum signals and other peripheric equipment signals possible




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Up to Different languages are included and can be selected such as English, German, French, Spanish, Chinese, etc Standard molding machine interface [SPI & E12] Full diagnosis with text error messages

Fig 2.13 Graphic LCD 2.6.3 LCD Port The LCD port provides the 14 standard signals required to interface to nearly all standard alphanumeric character mode displays from 8 to 80 characters. VDD provides +5 volt regulated power to the display (VSS is Ground). VEE ranges from 0 (maximum intensity) to 2 volts (minimum intensity) with the adjustment of the variable resistor located just above next to the power input. The E signal is an active high enable, which is asserted when the processor makes a memory access within the address range of 0xFE00 to 0xFEFF. RS and R/W are control lines for the display. In order to meet the timing requirements for all standard




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LCD displays, these are connected to the processor's address lines so they are asserted and remain stable while E is asserted. Because of this, separate locations are used to read and write to the LCD. Description Graphical LCD 128x64 controlled with the ATMega16, the graphic LCD GLCD HG1286418C-VA with a S6B0107/S6B0108 controller is used. See below for the pin out of the display. The display has 8 data bits and 5 control bits. The data bits are hooked to PORTB and the control bits are hooked to PORTD of the Mega16. A small PCB board is made for easy connection to the microcontroller. The program is made with the BASCOM-AVR compiler. The program shows text and a picture on the display. A library file needs to be included in the program, the library contains commands to control the display like:

Set font - Sets the current font which can be used on the graphical displays. Lcdat - shows text on the display $BGF - Includes a BASCOM Graphic File in the program. Showpic - shows a graphic file on the display Line - draws a line on the display Circle - draws a circle on the display Pset - Sets a single pixel on the display There are several fonts available like a 8x8 font and a 16x16 font, but the font file

consume memory, the large the font file the larger the program becomes. The core is used to provide a wishbone compliant interface to a graphical LCD. Currently it supports the Crystal fontz CFAG12864 family, which is based on the KS0108B controller. Other graphical LCDs may be supported at a later date. Advantages

No time consuming graphic programming




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Free Windows LCD simulator and development software No expensive software licenses required. Easy to learn powerful commands Fast development, drastically reduced time-to-market Touch-screen driver and analogue touch-screen included ( option -TP) Minimal electronics required to drive the display i.e. memory, I/O, low cost CPU Hardware cost savings due to the onboard memory and low pin count interface. Variety of serial interfaces ( 5V RS-232, IC, SPI ) Breakout boards with USB, RS232 and RS485 interface Display requires only a single +5V supply Extremely compact construction with DIP connectors at the back of LCD Stylish black alum. bezel and mounting system available LCD is available with analogue touch screen (order option -TP) Monochrome LCD's are available in blue/white, white/black positive FSTN and Amber Only best quality materials used Long products availability, recommended for industrial products

Applications

Medical equipment Restaurant ordering systems Lab development Student projects

2.6.4 Graphic LCD with Touch ScreenThese GLCD have common display drivers like KS0108 and T6963C and 4 wire resistive touch screen. There is no need for touch screen digitizer/controller for micro controllers having on chip ADC with four analog channels. Just connect the four wire of




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touch screen to analog inputs and read the respective digital data for X and Y direction of touched point.

Fig2.14: Graphic LCD with Touch Screen

2.6.5 Features Speeds from 19.2Kbps to a lighting fast 115Kbps 96 bit buffer 15872 bytes of memory! Store up to 30 full image screens Upload your own fonts for a customized look Communicate over RS232 or I2C Optional wide voltage efficient power regulator from +7 to +30Vdc (on GLC24064 & GLK24064-25) Extended Black and white ST (MST) Tran missive mode Built-in CCFL backlight 40 characters x 18 line capability




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240 x 128 dot graphic display Excellent readability and high-contrast ratio Built-in LCD controller (T6963C) Wide operating temperature range (0 to 50C)

2.6.6 Advantages of Graphic LCDs Download high quality fonts of any size, style or language easily and quickly. Create graphics using primitives such as bitmaps, pixels, lines, rectangles and bar graphs. Backlight & Contrast is adjustable in most models 4 different brightness settings General Purpose Output (20mA drive) Line wrap and Auto screen scroll Bar Graphs and Large Digits Speed settings Splash/Start-up Screen Some examples of graphic LCD controller chips are the Toshiba T6963, SeikoEpson SED1330, and Hitachi HD61202. Here, we will be primarily concerned with character LCD modules that have the Hitachi HD44780 controller built-in.

2.7 Zigbee technology2.7.1 Introduction When we hold the TV remote and wish to use it we have to necessarily point our control at the device. This one-way, line-of-sight, short-range communication usesNALLA MALLA REDDY ENGINEERING COLLEGE ELECTRONICS AND COMMUNICATION ENGINEERING


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infrared (IR) sensors to enable communication and control and it is possible to operate the TV remotely only with its control unit. Add other home theatre modules, an air- conditioner and remotely enabled fans and lights to our room, and we become a juggler who has to handle not only these remotes, but also more numbers that will accompany other home appliances we are likely to use. Some remotes do serve to control more than one device after memorizing' access codes, but this interoperability is restricted to LOS, that too only for a set of related equipment, like the different units of a home entertainment system Now picture a home with entertainment units, security systems including fire alarm, smoke detector and burglar alarm, air-conditioners and kitchen appliances all within whispering distance from each other and imagine a single unit that talks with all the devices, no longer depending on line-of-sight, and traffic no longer being one-way. This means that the devices and the control unit would all need a common standard to enable intelligible communication. Zigbee is such a standard for embedded application software and has been ratified in late 2004 under IEEE 802.15.4 Wireless Networking Standards. Zigbee is an established set of specifications for wireless personal area networking (WPAN), i.e., digital radio connections between computers and related devices. This kind of network eliminates use of physical data buses like USB and Ethernet cables. The devices could include telephones, hand-held digital assistants, sensors and controls located within a few meters of each other. Zigbee is one of the global standards of communication protocol formulated by the relevant task force under the IEEE 802.15 working group. The fourth in the series, WPAN Low Rate/Zigbee is the newest and provides specifications for devices that have low data rates, consume very low power and are thus characterized by long battery life.




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Other standards like Blue tooth and IrDA address high data rate applications such as voice, video and LAN communications. The Zigbee Alliance has been set up as an association of companies working together to enable reliable, cost-effective, low-power, wirelessly networked, monitoring and control products based on an open global standard. Once a manufacturer enrolls in this Alliance for a fee, he can have access to the standard and implement it in his products in the form of Zigbee chipsets that would be built into the end devices. Philips, Motorola, Intel, HP are all members of the Alliance. The goal is to provide the consumer with ultimate flexibility, mobility, and ease of use by building wireless intelligence and capabilities into every day devices. Zigbee technology will be embedded in a wide range of products and applications across consumer, commercial, industrial and government markets worldwide. For the first time, companies will have a standards-based wireless platform optimized for the unique needs of remote monitoring and control applications, including simplicity, reliability, low-cost and low-power. The target networks encompass a wide range of devices with low data rates in the Industrial, Scientific and Medical (ISM) radio bands, with building-automation controls like intruder/fire alarms, thermostats and remote (wireless) switches, video/audio remote controls likely to be the most popular applications. So far sensor and control devices have been marketed as proprietary items for want of a standard. With acceptance and implementation of Zigbee, interoperability will be enabled in multi-purpose, selforganizing mesh networks

2.7.2 Architecture Though WPAN implies a reach of only a few meters, 30 feet in the case of Zigbee, the network will have several layers, so designed as to enable interpersonal




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communication within the network, connection to a network of higher level and ultimately an uplink to the Web. The Zigbee Standard has evolved standardized sets of solutions, called layers'. These layers facilitate the features that make Zigbee very attractive: low cost, easy implementation, reliable data transfer, short-range operations, very low power consumption and adequate security features. 1. Network and Application Support layer The network layer permits growth of network sans high power transmitters. This layer can handle huge numbers of nodes. This level in the Zigbee architecture includes the Zigbee Device Object (ZDO), user-defined application profile(s) and the Application Support (APS) sub-layer. The APS sub-layer's responsibilities include maintenance of tables that enable matching between two devices and communication among them, and also discovery, the aspect that identifies other devices that operate in the operating space of any device. The responsibility of determining the nature of the device (Coordinator / FFD or RFD) in the network, commencing and replying to binding requests and ensuring a secure relationship between devices rests with the ZDO (Zigbee Define Object). The userdefined application refers to the end device that conforms to the Zigbee Standard. 2. Physical (PHY) layer: The IEEE802.15.4 PHY physical layer accommodates high levels of integration by using direct sequence to permit simplicity in the analog circuitry and enable cheaper implementations. 3. Media access control (MAC) layer:




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The IEEE802.15.4 MAC media access control layer permits use of several topologies without introducing complexity and is meant to work with large numbers of devices.

Figure 2.15 IEEE 802.15.4 / Zigbee Stack Architecture 2.7.3 Device types There are three different Zigbee device types that operate on these layers in any self-organizing application network. These devices have 64-bit IEEE addresses, with option to enable shorter addresses to reduce packet size, and work in either of two addressing modes star and peer-to-peer. 1. The Zigbee coordinator node There is one, and only one, Zigbee coordinator in each network to act as the router to other networks, and can be likened to the root of a (network) tree. It is designed to store information about the network. 2. The full function device FFD




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The FFD is an intermediary router transmitting data from other devices. It needs lesser memory than the Zigbee coordinator node, and entails lesser manufacturing costs. It can operate in all topologies and can act as a coordinator. 3. The reduced function device RFD This device is just capable of talking in the network; it cannot relay data from other devices. Requiring even less memory, (no flash, very little ROM and RAM), an RFD will thus be cheaper than an FFD. This device talks only to a network coordinator and can be implemented very simply in star topology.

2.7.4 Zigbee CharacteristicsThe focus of network applications under the IEEE 802.15.4 / Zigbee standard include the features of low power consumption, needed for only two major modes (Tx/Rx or Sleep), high density of nodes per network, low costs and simple implementation. These features are enabled by the following characteristics 2.4GHz and 868/915 MHz dual PHY modes. This represents three license-free bands: 2.4-2.4835 GHz, 868-870 MHz and 902-928 MHz. The number of channels allotted to each frequency band is fixed at sixteen (numbered 11-26), one (numbered 0) and ten (numbered 1-10) respectively. The higher frequency band is applicable worldwide, and the lower band in the areas of North America, Europe, Australia and New Zealand. Low power consumption, with battery life ranging from months to years. Considering the number of devices with remotes in use at present, it is easy to see that more numbers of batteries need to be provisioned every so often, entailing regular (as well as timely), recurring expenditure. In the Zigbee standard, longer battery life is achievable by either of two means: continuous network connection and slow but sure battery drain, or intermittent connection and even slower battery drain.




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Maximum data rates allowed for each of these frequency bands are fixed as 250 kbps @2.4 GHz, 40 kbps @ 915 MHz, and 20 kbps @868 MHz. High throughput and low latency for low duty-cycle applications ( Options. In this menu, setup the units for mm or in depending on how you think, and click see through the top copper layer at the bottom. The standard color scheme of red and green is generally used but it is not as pleasing as red and blue. 2. The Interface When a project is first started you will be greeted with a yellow outline. This yellow outline is the dimension of the PCB. Typically after positioning of parts and traces, move them to their final position and then crop the PCB to the correct size. However, in designing a board with a certain size constraint, crop the PCB to the correct size before starting.

Fig 5.1 toolbar of different functions

The select tool: It is fairly obvious what this does. It allows you to move and manipulate parts. When this tool is selected the top toolbar will show buttons to move traces to the top / bottom copper layer, and rotate buttons.

The zoom to selection tool: does just that. The place pad: button allows you to place small soldier pads which are useful for board connections or if a part is not in the part library but the part dimensions are




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available. When this tool is selected the top toolbar will give you a large selection of round holes, square holes and surface mount pads. The place component: tool allows you to select a component from the top toolbar and then by clicking in the workspace places that component in the orientation chosen using the buttons next to the component list. The components can always be rotated afterwards with the select tool if the orientation is wrong. The place trace: tool allows you to place a solid trace on the board of varying thicknesses. The top toolbar allows you to select the top or bottom layer to place the trace on. The Insert Corner in trace: button does exactly what it says. When this tool is selected, clicking on a trace will insert a corner which can be moved to route around components and other traces. The remove a trace button is not very important since the delete key will achieve the same result. 3. Design Considerations Before starting a project there are several ways to design a PCB and one must be chosen to suit the projects needs. Single sided, or double sided When making a PCB you have the option of making a single sided board, or a double sided board. Single sided boards are cheaper to produce and easier to etch, but much harder to design for large projects. If a lot of parts are being used in a small space it may be difficult to make a single sided board without jumpering over traces with a cable. While theres technically nothing wrong with this, it should be avoided if the signal traveling over the traces is sensitive (e.g. audio signals). A double sided board is more expensive to produce professionally, more difficult to etch on a DIY board, but makes the layout of components a lot smaller and easier. It should be noted that if a trace is running on the top layer, check with the components to make sure you can get to its pins with a soldering iron. Large capacitors, relays, andNALLA MALLA REDDY ENGINEERING COLLEGE ELECTRONICS AND COMMUNICATION ENGINEERING


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similar parts which dont have axial leads can NOT have traces on top unless boards are plated professionally. Ground-plane or other special purposes for one side: When using a double sided board you must consider which traces should be on what side of the board. Generally, put power traces on the top of the board, jumping only to the bottom if a part cannot be soldiered onto the top plane (like a relay), and viceversa. Some projects like power supplies or amps can benefit from having a solid plane to use for ground. In power supplies this can reduce noise, and in amps it minimizes the distance between parts and their ground connections, and keeps the ground signal as simple as possible. However, care must be taken with stubborn chips such as the TPA6120 amplifier from TI. The TPA6120 datasheet specifies not to run a ground plane under the pins or signal traces of this chip as the capacitance generated could affect performance negatively.

5.2 PIC CompilerPIC compiler is software used where the machine language code is written and compiled. After compilation, the machine source code is converted into hex code which is to be dumped into the microcontroller for further processing. PIC compiler also supports C language code. Its important that you know C language for microcontroller which is commonly known as Embedded C. As we are going to use PIC Compiler, hence we also call it PIC C. The PCB, PCM, and PCH are separate compilers. PCB is for 12-bit opcodes, PCM is for 14-bitopcodes, and PCH is for 16-bit opcode PIC microcontrollers. Due to many similarities, all three compilers are covered in this reference manual. Features and limitations that apply to only specific microcontrollers are indicated within. These compilers are specifically designed to meet the unique needs of the PIC microcontroller.




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This allows developers to quickly design applications software in a more readable, highlevel language. When compared to a more traditional C compiler, PCB, PCM, and PCH have some limitations. As an example of the limitations, function recursion is not allowed. This is due to the fact that the PIC has no stack to push variables onto, and also because of the way the compilers optimize the code. The compilers can efficiently implement normal C constructs, input/output operations, and bit twiddling operations. All normal C data types are supported along with pointers to constant arrays, fixed point decimal, and arrays of bits. PIC C is not much different from a normal C program. If you know assembly, writing a C program is not a crisis. In PIC, we will have a main function, in which all your application specific work will be defined. In case of embedded C, you do not have any operating system running in there. So you have to make sure that your program or main file should never exit. This can be done with the help of simple while (1) or for (;;) loop as they are going to run infinitely. We have to add header file for controller you are using, otherwise you will not be able to access registers related to peripherals. #include // header file for PIC 16F73// 5.3 Proteus Proteus is software which accepts only hex files. Once the machine code is converted into hex code, that hex code has to be dumped into the microcontroller and this is done by the Proteus. Proteus is a programmer which itself contains a microcontroller in it other than the one which is to be programmed. This microcontroller has a program in it written in such a way that it accepts the hex file from the pic compiler and dumps this hex file into the microcontroller which is to be programmed. As the Proteus programmer requires power supply to be operated, this power supply is given from the power supply




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circuit designed and connected to the microcontroller in proteus. The program which is to be dumped in to the microcontroller is edited in proteus and is compiled and executed to check any errors and hence after the successful compilation of the program the program is dumped in to the microcontroller using a dumper. Procedural steps for compilation, simulation and dumping: 5.4 Compilation and simulation steps For PIC microcontroller, PIC C compiler is used for compilation. The compilation steps are as follows: Open PIC C compiler. You will be prompted to choose a name for the new project, so create a separate folder where all the files of your project will be stored, choose a name and click save.

Fig 5.2 Picture of opening a new file using PIC C compiler




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Click Project, New, and something the box named 'Text1' is where your code should be written later. Now you have to click 'File, Save as' and choose a file name for your source code ending with the letter '.c'. You can name as 'project.c' for example and click save. Then you have to add this file to your project work.

Fig 5.3: Picture of compiling a new file using PIC C compiler




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Fig 5.4 Picture of compiling a project.c file using PIC C compiler

You can then start to write the source code in the window titled 'project.c' then before testing your source code; you have to compile your source code, and correct eventual syntax errors.




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Fig 5.5 Picture of checking errors and warnings using PIC C compiler

By clicking on compile option .hex file is generated automatically. This is how we compile a program for checking errors and hence the compiled program is saved in the file where we initiated the program.




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Fig 5.6 Picture of .hex file existing using PIC C compiler

After compilation, next step is simulation. Here first circuit is designed in Express PCB using Proteus 7 software and then simulation takes place followed by dumping. The simulation steps are as follows: Open Proteus 7 and click on IS1S6. Now it displays PCB where circuit is designed using microcontroller. To design circuit components are required. So click on component option. 10. Now click on letter p, then under that select PIC16F73 ,other components related to the project and click OK. The PIC 16F73 will be called your 'Target device, which is the final destination of your source code.




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5.3 Dumping steps: The steps involved in dumping the program edited in proteus 7 to microcontroller are shown below: 1. Initially before connecting the program dumper to the microcontroller kit the window is appeared as shown below.

Fig 5.7 Picture of program dumper window




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2. Select Tools option and click on Check Communication for establishing a connection as shown in below window

Fig 5.8 Picture of checking communications before dumping program into microcontroller




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3. After connecting the dumper properly to the microcontroller kit the window is appeared as shown below.

Fig 5.9 Picture after connecting the dumper to microcontroller




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4. Again by selecting the Tools option and clicking on Check Communication the microcontroller gets recognized by the dumper and hence the window is as shown below.

Fig 5.10 Picture of dumper recognition to microcontroller




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5. Import the program which is .hex file from the saved location by selecting File option and clicking on Import Hex as shown in below window.




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Fig 5.11 Picture of program importing into the microcontroller

6. After clicking on Import Hex option we need to browse the location of our programand click the prog.hex and click on open for dumping the program into the microcontroller.NALLA MALLA REDDY ENGINEERING COLLEGE ELECTRONICS AND COMMUNICATION ENGINEERING


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Fig 5.12 Picture of program browsing which is to be dumped




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7. After the successful dumping of program the window is as shown below.

Fig 5.13 Picture after program dumped into the microcontroller




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CHAPTER 6 ADVANTAGES AND DISADVANTAGES 6.1 Advantages1. Useful for illiterates and dumb people. 2. Basic needs can be served by gentle touch. 3. Low power consumption. 4. Very effective and efficient design. 5. Usage of wireless technology (Zigbee). 6. Can be used with any language. 7. Fast response.

6.2 Disadvantages1. Interfacing Touch screen to Microcontroller is sensitive. 2. Care should be taken in handling Touch screen.

6.3 ApplicationsThe applications of this project are: Very useful even for illiterates. Faster and secure data transmission. User friendly and easy to install. Helpful in abroad to express users needs. Deaf and dump people also can interact with others. Can be used with any languages.




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CHAPTER 7 RESULTS

7.1 ResultThe project Touch screen and Zigbee based wireless communication assistant for dumb /illiterates in airlines is designed as a user friendly communication system for illiterate/dumb people traveling by Airlines.

7.2 Kit Overview

Fig 7.1 Kit Overview




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Transmitter Inputs

Fig 7.2 Transmitter Images on GLCD




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CONCLUSIONS AND FUTURE SCOPEConclusionsIntegrating features of all the hardware components used have been developed in it. Presence of every module has been reasoned out and placed carefully, thus contributing to the best working of the unit. Secondly, using highly advanced ICs with the help of growing technology, the project has been successfully implemented. Thus the project has been successfully designed and tested.

Future ScopeOur project Touch screen and Zigbee based wireless communication assistant for dumb /illiterates in airlines is mainly intended to design a user friendly multi-language communication system for illiterate/dumb people traveling by Airlines. This project consists of Zigbee based system that transmits the wireless signals according to the input given by the user using touch screen. At the receiver (airhostess) end the information will be displayed on LCD in English language. Here when user sends his need through touch screen, then micro controller transmits that information through Zigbee transmitter. The information received by the Zigbee receiver will be displayed on LCD. This project provides an efficient device that helps dumb/illiterate to communicate with airhostess in airlines. Zigbee used in this project provides a typical range of 50m. By using high power Zigbee module we can extend this range up to 1.3 km. using Zigbee we can send text only. By using IR/RF transmitter and receiver we can send audio and video signals also. But Zigbee provides better data security and range is also more compared to IR. And another thing to be noted is Zigbee works in license freeNALLA MALLA REDDY ENGINEERING COLLEGE ELECTRONICS AND COMMUNICATION ENGINEERING


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bands. Zigbee is most preferable when data security is important. Further enhancements are yet to be made in the field of Zigbee. Touch screen used here is 4wire resistive touch screen. This is chosen because resistive touch screens stability and durability are more compared to other touch screens. Response time is also very less. It is resistant to intense light and not very sensitive as compared to other technologies but it accepts only one touch at a time. By using other technology like surface acoustic wave or infrared we can further improve project so that it can accept more than one touch at a time. But those touch screens are very sensitive and less resistant to intense light. And also they cant produce accurate results as they are sensitive to environment changes.




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REFERENCESSites referred 1. www.wikipedia.com 2. www.allaboutcircuits.com 3. www.microchip.com 4. www.howstuffworks.com Books referred 1. Raj kamal Microcontrollers Architecture, Programming, Interfacing and System Design, 2nd edition 2. Mazidi and Mazidi Embedded Systems,3rd edition 3. PCB Design Tutorial David.L.Jones 4. PIC Microcontroller Manual Microchip. 5. Embedded C Michael.J.Pont.



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