A MINI PROJECT REPORT

ON

TV REMOTE AS CORDLESS MOUSE FOR COMPUTER

By

A.Sindhuja 11B81A04C7 P.Sneha Sree 11B81A04D4 M.Swathi 11B81A04F8

Department of Electronics & Communication EngineeringCVR COLLEGE OF ENGINEERING(An Autonomous Institution, Affiliated to JNTUH, Accredited by NBA, AICTE)Vastunagar, Mangalpalli(V), Ibrahimpatnam(M), R.R.District, A.P2014

TV REMOTE AS CORDLESS MOUSE FOR COMPUTERA Mini Project Report submitted in the partial fulfillment of Requirements for the award of degree

BACHELOR OF TECHNOLOGYINELECTRONICS & COMMUNICATION ENGINEERING

BY

A.Sindhuja 11B81A04C7P.Sneha Sree11B81A04D4 M.Swathi 11B81A04F8

UNDER THE SUPERVISION OFMs. Ms. Dhruva R.Rinku, M.Tech.Senior Assistant Professor

Department of Electronics & Communication EngineeringCVR COLLEGE OF ENGINEERING(An Autonomous Institution, Affiliated to JNTUH, Accredited by NBA, AICTE)Vastunagar, Mangalpalli(V), Ibrahimpatnam(M), R.R.District, A.PWeb: http://cvr.ac.in Email: vlsi@cvr.ac.in, info@cvr.ac.in2014

Cherabuddi Education SocietysCVR COLLEGE OF ENGINEERING ACCREDITED BY NATIONAL BOARD OF ACCREDITATION, AICTE(Approved by A.I.C.T.E. & Govt. of Andhra Pradesh and Affiliated to JNT University)Vastunagar, Mangalpalli (V), Ibrahimpatnam (M), R.R. District, PIN 501 510Web: http://cvr.ac.in, email: info@cvr.ac.in Phones: Code within A.P.: 958414; Code from Outside: 08414 General: 252222, 252369 Office Telefax: 252396, Principal: 252396 (O)

Department of Electronics and Communication EngineeringCERTIFICATEThis is to certify that the mini project report entitled TV Remote as Cordless Mouse for Computer is submitted byA.Sindhuja 11B81A04C7P.Sneha Sree11B81A04D4 M.Swathi 11B81A04F8

in partial fulfillment of requirement for the award of Bachelor of Technology degree in Electronics and Communication Engineering from JNTUH, Kukatpally, Hyderabad for the academic year 2014-15.

Ms.Dhruva R.Rinku, M.Tech. Dr. K. S. Nayanathara Project Guide Head of the Department

ACKNOWLEDGEMENTFirst and foremost I express my deep sense of gratitude to the Almighty which cannot be described in words, for the blessings and strength the God has showered on me in fulfilling my aspirations and shall always be looking to his blessings.

I wish to express my deepest gratitude and thanks to Principal Prof. L.V.A.R. Sarma for his constant support and encouragement. At the outset, I am very much indebted to the Management of CVR COLLEGE OF ENGINEERING (CVRCE) for the valuable education imparted to me in the successful completion of the

I would like to express my gratitude to Dr. K. S. Nayanathara, Head of the Department, E.C.E, for No words can express my gratitude to my Parents, without whose support and encouragement this achievement would not have been possible. I also express my thanks to my friends and well-wishers who have extended their co-operation in this regard.

ABSTRACT The project is designed to use a TV remote as a cordless mouse for the computer. A conventional PC/laptop uses a mouse to operate and control all its applications. As a PC mouse is wired to the system, one has to sit near the PC to operate it. This becomes very tedious when the PC is used for presentation purposes (when using a projector). In this proposed system TV remote can be used as a cordless mouse, and the user need not operate the PC sitting near it. A typical TV remote sends coded infrared data that is read by an IR sensor interfaced to an 8051 family microcontroller. This data so received by the microcontroller sends it to the COM port of a PC through a level shifter IC. This IR code is traditionally RC5 code as followed by some manufacturers. Software named PC remote is used on the PC that recognizes data received from the microcontroller through the COM port and performs the required operation. Designated numbers on the TV remote are used to perform up - down, right - left cursor movement. Features like left click and right click of the mouse can also be performed with of the TV remote .Further this project can be enhanced using Bluetooth/ RF technology to overcome the traditional line of sight communication drawbacks of the infrared type. NOTE: The project works only on operating systems having hyper terminal (E.g. Windows XP). The computer must have a RS232 serial port. A.Sindhuja. (11B81A04C7) P.Sneha Sree. (11B81A04D4) M.Swathi. (11B81A04F8)

CONTENTS PAGE NO.1. INTRODUCTION 1.1 Introduction to Embedded systems 091.2 Objective 101.3 Thesis Organisation 102. BLOCK DIAGRAM EXPLANATION 2.1 Descriptioni. Power Supply 11 ii. Standard Connections to 8051 Series Microcontroller 12 iii. Reset 12iv. External Access 13v. MAX 232 13vi. Brief explanation of TSOP1738 13 3. HARDWARE REQUIREMENTS 3.1 Transformers 14 3.2 Voltage Regulator (LM7805) 16 3.3 Filter 18 3.4 Rectifier 19 3.5 Microcontroller (AT89S52/C51) 19 3.6 TSOP1738 26 3.7 MAX232 28 3.8 DB9 Connector 32 3.9 LED 33 3.10 Diode 1N4007 34 3.11 Resistors 35 3.12 Capacitors 36 4. SOFTWARE REQUIREMENTS4.1 IDE 374.2 Concept of Compiler 374.3 Concept of Cross Compiler 37 4.4 Building projects and Creating HEX Files 37 4.5 CPU Simulation 384.6 PC Remote Software 38 5. OPERATION 5.1 Connections 39 5.2 Working 39 5.3 Operation Procedure 39 6. HARDWARE TESTING 6.1 Continuity Test 406.2 Power on Test 407. RESULTS 428. CONCLUSION 449. BIBLIOGRAPHY 45

45

LIST OF FIGURES PAGE NO 2. Block Diagram 113.1 A Typical Transformer 143.2(a) Block Diagram of Voltage Regulator 17 3.2(b) Rating of Voltage Regulator 173.5(a) Block Diagram of AT89S52 223.5(b) Pin Diagram of AT89S52 233.5(c) Oscillator Connections 253.6(a) TSOP1738 263.6(b) TSOP Block Diagram 273.7(a) Pin Diagram of MAX232 30 3.8(a) DB9 Connector 323.9(a) Symbol of LED 34

1. INTRODUCTION

1.1 INTRODUCTION TO EMBEDDED SYSTEMSWhat is embedded system?An Embedded System is a combination of computer hardware and software, and perhaps additional mechanical or other parts, designed to perform a specific function. 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 an minimal operating systems and hardware layout designed for the specific purpose. Examples Small controllers and devices in our everyday life like Washing Machine, Microwave Ovens, where they are embedded in. CLASSIFICATION:1. Real Time Systems.1. RTS is one which has to respond to events within a specified deadline.1. A right answer after the dead line is a wrong answer.RTS CLASSIFICATION:1. Hard Real Time Systems1. Soft Real Time SystemHARD 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.1.2. OBJECTIVEIn this technology driven days everything is made easy and simple. The main objective of this project is designed to control computer using TV remote.1.3. THESIS ORGANISATION: The rest of the chapters in the thesis organized as follows: Chapter 2 illustrates about the Block diagram and explains all the blocks. Chapter 3 illustrates about all the hardware components used in the project. Chapter 4 illustrates about the software requirements of the project. Chapter 5 illustrates about the operation and implementation of the project. Chapter 6 explains the result of project.

2. BLOCK DIAGRAM

2.1 DESCRIPTION i. POWER SUPPLY:The circuit uses standard power supply comprising of a step-down transformer from 230Vto 12V and 4 diodes forming a bridge rectifier that delivers pulsating dc which is then filtered by an electrolytic capacitor of about 470F to 1000F. The filtered dc being unregulated, IC LM7805 is used to get 5V DC constant at its pin no 3 irrespective of input DC varying from 7V to 15V. The input dc shall be varying in the event of input ac at 230volts section varies from 160V to 270V in the ratio of the transformer primary voltage V1 to secondary voltage V2 governed by the formula V1/V2=N1/N2. As N1/N2 i.e. no. of turns in the primary to the no. of turns in the secondary remains unchanged V2 is directly proportional to V1.Thus if the transformer delivers 12V at 220V input it will give 8.72V at 160V.Similarly at 270V it will give 14.72V.Thus the dc voltage at the input of the regulator changes from about 8V to 15V because of A.C voltage variation from 160V to 270V the regulator output will remain constant at 5V. The regulated 5V DC is further filtered by a small electrolytic capacitor of 10F for any noise so generated by the circuit. One LED is connected of this 5V point in series with a current limiting resistor of 330 to the ground i.e., negative voltage to indicate 5V power supply availability. The unregulated 12V point is used for other applications as and when required.ii. STANDARD CONNECTIONS TO 8051 SERIES MICRO- CONTROLLER: ATMEL series of 8051 family of micro controllers need certain standard connections. The actual number of the Microcontroller could be 89C51 , 89C52, 89S51, 89S52, andas regards to 20 pin configuration a number of 89C2051. The 4 set of I/O ports are used based on the project requirement. Every microcontroller requires a timing reference for its internal program execution therefore an oscillator needs to be functional with a desired frequency to obtain the timing reference as t =1/f. A crystal ranging from 2 to 20 MHz is required to be used at its pin number 18 and 19 for the internal oscillator. It may be noted here the crystal is not to be understood as crystal oscillator It is just a crystal, while connected to the appropriate pin of the microcontroller it results in oscillator function inside the microcontroller. Typically 11.0592 MHz crystal is used in general for most of the circuits using 8051 series microcontroller. Two small value ceramic capacitors of 33pF each is used as a standard connection for the crystal as shown in the circuit diagram.iii. RESET:Pin no 9 is provided with a re-set arrangement by a combination of an electrolytic capacitor and a register forming RC time constant. At the time of switch on, the capacitor gets charged, and it behaves as a full short circuit from the positive to the pin number 9.After the capacitor gets fully charged the current stops flowing and pin number 9 goes low which is pulled down by a 10k resistor to the ground. This arrangement of reset at pin 9 going high initially and then to logic 0 i.e., low helps the program execution to start from the beginning. In absence of this the program execution could have taken place arbitrarily anywhere from the program cycle. A pushbutton switch is connected across the capacitor so that at any given time as desired it can be pressed such that it discharges the capacitor and while released the capacitor starts charging again and then pin number 9 goes to high and then back to low, to enable the program execution from the beginning. This operation of high to low of the reset pin takes place in fraction of a second as decided by the time constant R and C.iv. External Access(EA): Pin no 31 of 40 pin 8051 microcontroller termed as EA is required to be connected to 5V for accessing the program form the on-chip program memory. If it is connected to ground then the controller accesses the program from external memory. However as we are using the internal memory it is always connected to +5V. v. MAX232: The MAX232 used in the project is an integrated circuit that converts signals from an RS-232 serial port to signals suitable for use in TTL compatible digital logic circuits like microcontroller. The MAX232 is a dual driver/receiver and typically converts the RX, TX, CTS and RTS signals.vi. BRIEF EXPLANATION OF TSOP 1738: TheTSOP 1738is a member ofIR remote control receiverseries. This IR sensor module consists of a PIN diode and a pre amplifier which are embedded into a single package. The output ofTSOPis active low and it gives +5V in off state. When IR waves, from a source, with a center frequency of 38 kHz incident on it, its output goes low.TSOP modulehas an inbuilt control circuit for amplifying the coded pulses from the IR transmitter. A signal is generated when PIN photodiode receives the signals. This input signal is received by an automatic gain control (AGC). For a range of inputs, the output is fed back to AGC in order to adjust the gain to a suitable level. The signal from AGC is passed to a band pass filter to filter undesired frequencies. After this, the signal goes to a demodulator and this demodulated output drives an npn transistor. The collector output of the transistor is obtained at pin 3 of TSOP module.

3. HARDWARE REQUIREMENTS

HARDWARE COMPONENTS:1. TRANSFORMER (230 12 V AC)2. VOLTAGE REGULATOR (LM 7805)3. FILTER4. RECTIFIER5. MICROCONTROLLER (AT89S52/AT89C51) 6. TSOP17387. MAX2328. DB9 CONNECTOR9. LED10. 1N400711. RESISTORS12. CAPACITORS3.1 TRANSFORMER: Transformers convert AC electricity from one voltage to another with a little loss of power. Step-up transformers increase voltage, step-down transformers reduce voltage. Most power supplies use a step-down transformer to reduce the dangerously high voltage to a safer low voltage.

FIG 3.1: A TYPICAL TRANSFORMER

The input coil is called the primary and the output coil is called the secondary. There is no electrical connection between the two coils; instead they are linked by an alternating magnetic field created in the soft-iron core of the transformer. The two lines in the middle of the circuit symbol represent the core. Transformers waste very little power so the power out is (almost) equal to the power in. Note that as voltage is stepped down and current is stepped up. The ratio of the number of turns on each coil, called the turns ratio, determines the ratio of the voltages. A step-down transformer has a large number of turns on its primary (input) coil which is connected to the high voltage mains supply, and a small number of turns on its secondary (output) coil to give a low output voltage. TURNS RATIO = (Vp /Vs) = ( Np / Ns )Where,

Vp = primary (input) voltage.Vs = secondary (output) voltageNp = number of turns on primary coilNs = number of turns on secondary coilIp = primary (input) current Is= secondary (output) current.Ideal power equation:

The ideal transformer as a circuit elementIf the secondary coil is attached to a load that allows current to flow, electrical power is transmitted from the primary circuit to the secondary circuit. Ideally, the transformer is perfectly efficient; all the incoming energy is transformed from the primary circuit to the magnetic field and into the secondary circuit. If this condition is met, the incoming electric power must equal the outgoing power:

3.2 VOLTAGE REGULATOR 7805:Features: Output Current up to 1A. Output Voltages of 5, 6, 8, 9, 10, 12, 15, 18, 24V. Thermal Overload Protection. Short Circuit Protection. Output Transistor Safe Operating Area Protection.

Circuit DiagramDescription:The LM78XX/LM78XXA series of three-terminal positive regulators are available in the TO-220/D-PAK package and with several fixed output voltages, making them useful in a Wide range of applications. Each type employs internal current limiting, thermal shutdown and safe operating area protection, making it essentially indestructible. If adequate heat sinking is provided, they can deliver over 1A output Current. Although designed primarily as fixed voltage regulators, these devices can be used with external components to obtain adjustable voltages and currents.

Internal Block Diagram:

FIG 3.2(a): BLOCK DIAGRAM OF VOLTAGE REGULATORAbsolute Maximum Ratings TABLE 3.2(b): RATINGS OF THE VOLTAGE REGULATOR

3.3 RECTIFIER:A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), current that flows in only one direction, a process known as rectification. Rectifiers have many uses including as components of power supplies and as detectors of radio signals. Rectifiers may be made of solid state diodes, vacuum tube diodes, mercury arc valves, and other components. The output from the transformer is fed to the rectifier. It converts A.C. into pulsating D.C. The rectifier may be a half wave or a full wave rectifier. In this project, a bridge rectifier is used because of its merits like good stability and full wave rectification. In positive half cycle only two diodes( 1 set of parallel diodes) will conduct, in negative half cycle remaining two diodes will conduct and they will conduct only in forward bias only.

3.4 FILTER:

Capacitive filter is used in this project. It removes the ripples from the output of rectifier and smoothens the D.C. Output received from this filter is constant until the mains voltage and load is maintained constant. However, if either of the two is varied, D.C. voltage received at this point changes. Therefore a regulator is applied at the output stage.The simple capacitor filter is the most basic type of power supply filter. The use of this filter is very limited. It is sometimes used on extremely high-voltage, low-current power supplies for cathode-ray and similar electron tubes that require very little load current from the supply. This filter is also used in circuits where the power-supply ripple frequency is not critical and can be relatively high. Below figure can show how the capacitor charges and discharges.

3.5 MICROCONTROLLER AT89S52:The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with 8K bytes of in-system programmable Flash memory. The device is manufactured using Atmels high-density non-volatile memory technology and is compatible with the industry standard 80C51 instruction set and pin out. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional non-volatile memory programmer. By combining a versatile 8-bit CPU with in-system programmable Flash on a monolithic chip, the Atmel AT89S52 is a powerful microcontroller which provides a highly-flexible and cost-effective solution to many embedded control applications. Features: Compatible with MCS-51 Products 8K Bytes of In-System Programmable (ISP) Flash Memory Endurance: 10,000 Write/Erase Cycles 4.0V to 5.5V Operating Range Fully Static Operation: 0 Hz to 33 MHz Three-level Program Memory Lock 256 x 8-bit Internal RAM 32 Programmable I/O Lines Three 16-bit Timer/Counters Eight Interrupt Sources Full Duplex UART Serial Channel Low-power Idle and Power-down Modes Interrupt Recovery from Power-down Mode Watchdog Timer Dual Data Pointer Power-off Flag Fast Programming Time Flexible ISP Programming (Byte and Page Mode) Green (Pb/Halide-free) Packaging Option

Block Diagram of AT89S52: Fig 3.5: Block Diagram Of AT89S52

Pin Configurations of AT89S52:

FIG 3.5(b): PIN DIAGRAM OF AT89S52

Pin Description:

VCC: Supply voltage.GND:Ground.

Port 0: Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can sink eight TTL inputs. Port 0 also receives the code bytes during Flash programming and outputs the code bytes during program verification. External pull-ups are required during program verification.Port 1:Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 1 output buffers can sink/source four TTL inputs. P1.0 and P1.1 can be configured to be the timer/counter 2 external count input (P1.0/T2) and the timer/counter 2 trigger input (P1.1/T2EX).Port 2:Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 2 output buffers can sink/source four TTL inputs. Port 2 uses strong internal pull-ups when emitting 1s. During accesses to external data memory that uses 8-bit addresses (MOVX @ RI), Port 2 emits the contents of the P2 Special Function Register.Port 3:Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 3 output buffers can sink/source four TTL inputs. Port 3 pins that are externally being pulled low will source current (IIL) because of the pull-ups.RST:Reset input. A high on this pin for two machine cycles while the oscillator is running resets the device. ALE/PROG:Address Latch Enable (ALE) is an output pulse for latching the low byte of the address during accesses to external memory. This pin is also the program pulse input (PROG) during Flash programming. In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator frequency and may be used for external timing or clocking purposes. However, that one ALE pulse is skipped during each access to external data memory.PSEN:Program Store Enable (PSEN) is the read strobe to external program memory. When the AT89S52 is executing code from external program memory, PSEN is activated twice each machine cycle, except that two PSEN activations are skipped during each access to external data memory.EA/VPP:External Access Enable EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC for internal program executions. This pin also receives the 12-volt programming enable voltage (VPP) during Flash programming.XTAL1:Input to the inverting oscillator amplifier and input to the internal clock operating circuit.XTAL2:Output from the inverting oscillator amplifier.Oscillator Characteristics: XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier which can be configured for use as an on-chip oscillator. Either a quartz crystal or ceramic resonator may be used. To drive the device from an external clock source, XTAL2 should be left unconnected while XTAL1 is driven.

FIG 3.5(c): Oscillator

Idle Mode: In idle mode, the CPU puts itself to sleep while all the on chip peripherals remain active. The mode is invoked by software. The content of the on-chip RAM and all the special functions registers remain unchanged during this mode. The idle mode can be terminated by any enabled interrupt or by a hardware reset.Power down Mode: In the power down mode the oscillator is stopped, and the instruction that invokes power down is the last instruction executed. The on-chip RAM and Special Function Registers retain their values until the power down mode is terminated. The only exit from power down is a hardware reset. 3.6 TSOP1738:Description: The TSOP17 series are miniaturized receivers for infrared remote control systems. PIN diode and preamplifier are assembled on lead frame, the epoxy package is designed as IR filter.The demodulated output signal can directly be decoded by a microprocessor. TSOP1738 is the standard IR remote control receiver series, supporting all major transmission codes.Features: Photo detector and preamplifier in one package Internal filter for PCM frequency Improved shielding against electrical field disturbance TTL and CMOS compatibility Output active low Low power consumption High immunity against ambient light Continuous data transmission possible (up to 2400 bps) Suitable burst length >=10 cycles/burstFIG 4.6(a) TSOP 1738

Block diagram of TSOP:

The circuit of the TSOP17 is designed in that way that unexpected output pulses due to noise or disturbance signals are avoided. A band pass filter, an integrator stage and an automatic gain control are used to suppress such disturbances. The distinguishing mark between data signal and disturbance signal are carrier frequency, burst length and duty cycle. The data signal should full fill the following condition: Carrier frequency should be close to center frequency of the band pass (e.g. 38kHz). Burst length should be 10 cycles/burst or longer. After each burst which is between 10 cycles and 70 cycles a gap time of at least 14 cycles is necessary. For each burst which is longer than 1.8ms a corresponding gap time is necessary at some time in the data stream. This gap time should have at least same length as the burst. Up to 1400 short bursts per second can be received continuously. Some examples for suitable data format are: NEC Code, Toshiba Micom Format, Sharp Protocol, RC5 Protocol, RC6 Protocol, R2000 Protocol, Sony Format (SIRCS). When a disturbance signal is applied to the TSOP17.It can still receive the data signal. However the sensitivity is reduced to that level that no unexpected pulses will occur. Some examples for such disturbance signals which are suppressed by the TSOP17 series are: DC light (e.g. from tungsten bulb or sunlight) Continuous signal at 38 kHz or at any other frequency In this project we use RC5 protocol which converts the information from remote into pulses and modulates it and sends to microcontroller. The RC5 - code has an instruction set of 2048 different instructions and is divided into 32 addresses (5 bits) of each 64 instructions or commands (6 bits). The transmitted code is a data word that consists of 14 bits and is defined as:2 start bits (ss) for the automatic gain control in the infrared receiver.ss = 10 (Add 64 to command)ss = 11 (Use command as it is)The command set can be increased by 64 commands by using a modified start bit 10 instead of 11 using the second start bit as7th command bit. 1 toggle bit (change every time when a new button is pressed on the IR transmitter) 5 address bits for the system address. 6 instruction bits for the command or key pressed.The RC5 code uses the Bi-Phase modulation technique, meaning that a single bit is split up into two half bits:0 -> 101 -> 01The duration time of each bit is equal to 1.778ms containing32 pulses with a repetition rate of 36 kHz, the carrier frequency of this code. The total time of a fullRC5 code is 24.889ms. The space between two transmitted codes is 50 bit times or 88.889ms. The carrier frequency is used to enable a narrow band reception to improve the noise rejection. The carrier frequency of the RC5 code is 36 kHz. The complete signal is repeated every 114ms as long as the command button is still pressed. The toggle bit is changing its polarity each time the button is pressed.

3.7 MAX232:The MAX232 is an integrated circuit that converts signals from an RS-232 serial port to signals suitable for use in TTL compatible digital logic circuits. The MAX232 is a dual driver/receiver and typically converts the RX, TX, CTS and RTS signals.The drivers provide RS-232 voltage level outputs (approx. 7.5V) from a single +5V supply via on-chip charge pumps and external capacitors. This makes it useful for implementing RS-232 in devices that otherwise do not need any voltages outside the 0V to +5V range, as power supply design does not need to be made more complicated just for driving the RS-232 in this case. The receivers reduce RS-232 inputs (which may be as high as 25V), to standard 5V TTL levels. These receivers have a typical threshold of 1.3V, and a typical hysteresis of 0.5V.The later MAX232A is backwards compatible with the original MAX232 but may operate at higher baud rates and can use smaller external capacitors (0.1F) in place of the 1.0F capacitors used with the original device. The newer MAX3232 is also backwards compatible, but operates at a broader voltage range, from 3 to 5.5V.

Voltage levels:It is helpful to understand what occurs to the voltage levels. When a MAX232 IC receives a TTL level to convert, it changes a TTL Logic 0 to between +3 and +15V, and changes TTL Logic 1 to between -3 to -15V, and vice versa for converting from RS232 to TTL. This can be confusing when you realize that the RS232 Data Transmission voltages at a certain logic state are opposite from the RS232 Control Line voltages at the same logic state. To clarify the matter, see the table below. For more information see RS-232 Voltage Levels.

FIG3.7(a):Pin Diagram of MAX-232Pin Description:

Application:The MAX232 has two receivers (converts from RS-232 to TTL voltage levels) and two drivers (converts from TTL logic to RS-232 voltage levels). This means only two of the RS-232 signals can be converted in each direction.

Typically a pair of a driver/receiver of the MAX232 is used for TX and RX And the second one for CTS and RTS. There are not enough drivers/receivers in the MAX232 to also connect the DTR, DSR, and DCD signals. Usually these signals can be omitted when e.g. communicating with a PC's serial interface. If the DTE really requires these signals either a second MAX232 is needed, or some other IC from the MAX232 family can be used.

3.8 DB9 CONNECTOR:The DB9 (originally DE-9) connector is an analog 9-pin plug of the D-Sub miniature connector family (D-Sub or Sub-D). The DB9 connector is mainly used for serial connections, allowing for the asynchronous transmission of data as provided for by standard RS-232 (RS-232C).

Fig 3.8: DB9 CONNECTORPin description:

This is a common connector used in many computer, audio/video, and data applications. The official name is D-sub miniature, but many people call it D-sub or just DB. The connector gets its name from its trapezoidal shape that resembles the letter D. Most DB connectors have two rows of pins. Common types of D-sub connectors are DB9 and DB25, used on PCs for serial and parallel ports. Interfacing Between Microcontroller and Db9 Connector:

3.9 LED:

A light-emitting diode (LED) is a semiconductor light source. LEDs are used as indicator lamps in many devices, and are increasingly used for lighting. When a light-emitting diode is forward biased (switched on), electrons are able to recombine with holes within the device, releasing energy in the form of photons. This effect is called electroluminescence and the color of the light (corresponding to the energy of the photon) is determined by the energy gap of the semiconductor. An LED is often small in area (less than 1mm2), and integrated optical components may be used to shape its radiation pattern. LEDs present many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved robustness, smaller size, faster switching, and greater durability and reliability. Light-emitting diodes are used in applications as diverse as replacements for aviation lighting, automotive lighting as well as in traffic signals. The compact size, the possibility of narrow bandwidth, switching speed, and extreme reliability of LEDs has allowed new text and video displays and sensors to be developed, while their high switching rates are also useful in advanced communications technologyElectronic Symbol:

Fig 3.9(a): symbol of LED

3.10 Diode 1N4007 Diodes are used to convert AC into DC these are used as half wave rectifier or full wave rectifier. Three points must he kept in mind while using any type of diode. 1. Maximum forward current capacity 2. Maximum reverse voltage capacity 3. Maximum forward voltage capacity

Fig: 1N4007 diodesThe number and voltage capacity of some of the important diodes available in the market are as follows: Diodes of number IN4001, IN4002, IN4003, IN4004, IN4005, IN4006 and IN4007 have maximum reverse bias voltage capacity of 50V and maximum forward current capacity of 1 Amp.

Fig:PN Junction diode3.11 RESISTORS:A resistor is a two-terminal electronic component designed to oppose an electric current by producing a voltage drop between its terminals in proportion to the current, that is, in accordance with Ohm's law: V = IRResistors are used as part of electrical networks and electronic circuits. They are extremely common in most electronic equipment. Practical resistors can be made of various compounds and films, as well as resistance wire (wire made of a high-resistivity alloy, such as nickel/chrome).The primary characteristics of resistors are their resistance and the power they can dissipate. Other characteristics include temperature coefficient, noise, and inductance.

A resistor is a two-terminal passive electronic component which implements electrical resistance as a circuit element. When a voltage V is applied across the terminals of a resistor, a current I will flow through the resistor in direct proportion to that voltage. The reciprocal of the constant of proportionality is known as the resistance R, since, with a given voltage V, a larger value of R further "resists" the flow of current I as given by Ohm's law

Units:The ohm (symbol: ) is the SI unit of electrical resistance, named after Georg Simon Ohm. An ohm is equivalent to a volt per ampere 3.12 CAPACITORS: A capacitor or condenser is a passive electronic component consisting of a pair of conductors separated by a dielectric. When a voltage potential difference exists between the conductors, an electric field is present in the dielectric. This field stores energy and produces a mechanical force between the plates. The effect is greatest between wide, flat, parallel, narrowly separated conductors.An ideal capacitor is characterized by a single constant value, capacitance, which is measured in farads. This is the ratio of the electric charge on each conductor to the potential difference between them.

Charge separation in a parallel-plate capacitor causes an internal electric field. A dielectric (orange) reduces the field and increases the capacitance.

4. SOFTWARE REQUIREMENTS:4.1 INTRODUCTION TO KEIL MICRO VISION (IDE): Keil an ARM Company makes C compilers, macro assemblers, real-time kernels, debuggers, simulators, integrated environments, evaluation boards, and emulators for ARM7/ARM9/Cortex-M3, XC16x/C16x/ST10, 251, and 8051 MCU families. Keil development tools for the 8051 Microcontroller Architecture support every level of software developer from the professional applications engineer to the student just learning about embedded software development. Keil is a cross compiler. 4.2 CONCEPT OF COMPILER:Compilers are programs used to convert a High Level Language to object code. Desktop compilers produce an output object code for the underlying microprocessor, but not for other microprocessors i.e the programs written in one of the HLL like Cwill compile the code to run on the system for a particular processor like x86 (underlying microprocessor in the computer). The compiler derives its name from the way it works, looking at the entire piece of source code and collecting and reorganizing the instruction. However compilers require some time before an executable program emerges. Now as compilers translate source code into object code, which is unique for each type of computer, many compilers are available for the same language.4.3 CONCEPT OF CROSS COMPILER:A cross compiler is similar to the compilers but we write a program for the target processor (like 8051 and its derivatives) on the host processors (like computer of x86). It means being in one environment you are writing a code for another environment is called cross development. And the compiler used for cross development is called cross compiler.So the definition of cross compiler is a compiler that runs on one computer but produces object code for a different type of computer.

4.4 Building Projects and Creating a HEX Files:Typical, the tool settings under Options Target are all you need to start a new application. You may translate all source files and line the application with a click on the Build Target toolbar icon. When you build an application with syntax errors, Vision2 will display errors and warning messages in the Output Window Build page. A double click on a message line opens the source file on the correct location in a Vision2 editor window. Once you have successfully generated your application you can start debugging. After you have tested your application, it is required to create an Intel HEX file to download the software into an EPROM programmer or simulator. Vision2 creates HEX files with each build process when Create HEX files under Options for Target Output is enabled. You may start your PROM programming utility after the make process when you specify the program under the option Run User Program #1.4.5 CPU Simulation:Vision2 simulates up to 16 Mbytes of memory from which areas can be mapped for read, write, or code execution access. The Vision2 simulator traps and reports illegal memory accesses. In addition to memory mapping, the simulator also provides support for the integrated peripherals of the various 8051 derivatives. The on-chip peripherals of the CPU you have selected are configured from the Device. 4.6 PC REMOTE SOFTWARE: PC Remote software is an easy to use and reliable application that can provide you with remote access to a computer allowing you to control its actions. With the help of this software all the instruction related to mouse in computer operating system are interfaced with sensor and microcontroller and work on the information sent by the remote. It has some built in methods and instructions which helps the remote act as mouse.

5. OPERATION5.1 Connections:The output of power supply which is 5v is connected to the 40th pin of microcontroller &Gnd is connected to 20th pin of microcontroller. Pin 3.0 of port 3 of microcontroller are connected to pins 11 & 12 of Max232.Pins 13 and 14 of Max232 are given to pins 2 and 3 of DB9 connector. Pin 3.3 of port 3 of microcontroller are given to 3rd pin of TSOP1738.

5.2 Working: The project uses an IR receiver such as TSOP1738 that responds to only specific frequency of 38 kHz, in order to avoid receiving false signal from normal environmental infrared sources. The output of this receiver is interfaced to interrupt 1 i.e., pin 13 of the microcontroller. A standard TV remote that delivers infrared codes at 38 kHz is thus received by the TSOP receiver feeding a 14 bit data so emitted from the remote to the controller through receiver. The program is so returned that it recognizes the 14 bit data relating to a particular number being pressed at the remote.Here the TV remote buttons are used for sending specific 14 bit data to pin 13 of port 3.3. Software used at the PC receives these commands through the serial port being connected to the MC through MAX232, RS232 interface. Thus the TV remote works like a mouse from a distance.5.3 Operation Proceedure: Run PC control software Select com1 and select enable option 2 = up arrow 5 = down arrow 4 = left arrow 6 = right arrow 1 = left click 3 = right click Volume+ = to increase cursor speed Volume- = to decrease cursor speed

6. HARDWARE TESTING6.1 CONTINUITY TEST:In electronics, a continuity test is the checking of an electric circuit to see if current flows (that it is in fact a complete circuit). A continuity test is performed by placing a small voltage (wired in series with an LED or noise-producing component such as a piezoelectric speaker) across the chosen path. If electron flow is inhibited by broken conductors, damaged components, or excessive resistance, the circuit is "open".Devices that can be used to perform continuity tests include multi meters which measure current and specialized continuity testers which are cheaper, more basic devices, generally with a simple light bulb that lights up when current flows.An important application is the continuity test of a bundle of wires so as to find the two ends belonging to a particular one of these wires; there will be a negligible resistance between the "right" ends, and only between the "right" ends.This test is the performed just after the hardware soldering and configuration has been completed. This test aims at finding any electrical open paths in the circuit after the soldering. Many a times, the electrical continuity in the circuit is lost due to improper soldering, wrong and rough handling of the PCB, improper usage of the soldering iron, component failures and presence of bugs in the circuit diagram. We use a multi meter to perform this test. We keep the multi meter in buzzer mode and connect the ground terminal of the multi meter to the ground. We connect both the terminals across the path that needs to be checked. If there is continuation then you will hear the beep sound.6.2 POWER ON TEST:This test is performed to check whether the voltage at different terminals is according to the requirement or not. We take a multi meter and put it in voltage mode. Remember that this test is performed without microcontroller. Firstly, we check the output of the transformer, whether we get the required 12 v AC voltage.

Then we apply this voltage to the power supply circuit. Note that we do this test without microcontroller because if there is any excessive voltage, this may lead to damaging the controller. We check for the input to the voltage regulator i.e., are we getting an input of 12v and an output of 5v. This 5v output is given to the microcontrollers 40th pin. Hence we check for the voltage level at 40th pin. Similarly, we check for the other terminals for the required voltage. In this way we can assure that the voltage at all the terminals is as per the requirement.

7. RESULTSThis figure gives the view of the circuit after all the connections are made.

This figure gives the view of the circuit when power is supplied to circuit.

This figure illustrates the first stage of running PC Remote software i.e. selecting one of the available COM Ports.

This figure illustrates the second stage of running software i.e. enabling the COM Port.

This figure illustrates the completion of running software and now if we want to stop software simply we need to select disable.

8. CONCLUSION Thus, by using this project TV remote can be used as a cordless mouse for Computer by using TV remote software. The information from remote is sensed by an IR sensor and is converted into microcontroller compatible format and the computer is interfaced to the sensor. The software makes all the instructions of the mouse in kernel compatible to remote instructions. By pressing some buttons in mouse the following actions take place: 2 = up arrow 5 = down arrow 4 = left arrow 6 = right arrow 1 = left click 3 = right click Volume+ = to increase cursor speed Volume- = to decrease cursor speed

13. BIBLIOGRAPHYTEXT BOOKS REFERED:

1. The 8051 Microcontroller and Embedded systems by Muhammad Ali Mazidi and Janice Gillispie Mazidi, Pearson Education.2. ATMEL 89S52 Data Sheets.

WEBSITES

www.atmel.com www.beyondlogic.org www.wikipedia.org www.howstuffworks.com www.alldatasheets.com