Navigation Robot Document Ion

Navigation Robot

Introduction

Autonomous navigation of a mobile robot is a challenging task. Much work has been done in indoor navigation in the last decade. Fewer results have been obtained in outdoor robotics. Since the early 90's, the Global Positioning System (GPS) has been the main navigation system for ships and aircrafts. In open fields, satellite navigation gives absolute position accuracy. The absolute heading information is also obtained by satellite navigation when the mobile robot is in motion. However, the use of GPS satellite navigation is mainly restricted to open areas where at least three satellites can be seen. For example, mobile robots working in underground or deep open mines cannot use satellite navigation at all, and in forest or city areas, there are serious limitations to its use. It is obvious that the use of several alternative sensors according to the environment will make the navigation system more flexible. The goal of this thesis is to develop a multi sensor navigation system for unknown outdoor environments. Navigation should be possible in unstructured outdoors as well as indoor environments. The system should use all available sensor information and emphasize those that best suit the particular environment. The sensors considered in this thesis include a temperature sensor, camera sensor and light dependent resistor. The main contribution of the thesis is a flexible navigation system developed and tested for performing versatile tasks in an outdoor environment. Today’s men rely heavily on robotics, which are capable of penetrating areas where manned vehicles cannot enter while keeping humans out of harm’s way. Similarly there cannot be lost with impunity; they cannot enter into or create toxic environments. One must avoid both the purely negative consequences that are positive for one's enemies (the taking of prisoners of war, hostages and other potential sources of sensitive information). And also they face severe threat from these Unmanned Air Vehicles.

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Robots are tremendously flexible devices, and can also be used for a variety of purposes like navigation of unknown areas, defusing land mines, patrolling at boarders, etc. Nowadays, with the advancement of technology, particularly in the field of computers, micro processors, micro controllers and communications, all the activities in our day-to-day living have become a part of information and we find computers and micro controllers at each and every application. In our project we used micro controllers connected with FM transmitter at base station to send commands to navigation robot. At vehicle end we used micro controller connected with FM receiver to receive commands, and to control movements of the vehicle. Stepper motors are used for driving the vehicle because they rotate in precise angles, so that we can control the vehicle precisely at required directions. We are using total three stepper motors. Two for forward, reverse, left and right directions. Third one is used for rotating camera position in to different angels. If the first two motors coupled to wheels, are moving in clock wise direction then the vehicle moves in forward direction and If they are moving in anti clock wise direction then the vehicle moves in reverse direction. If left motor is rotating with more speed and right motor is rotating with less speed, then the vehicle turns towards right direction. Similarly if right motor is rotating with more speed and left motor is rotating with less speed, then the vehicle turn towards left direction. If the third motor moves in clockwise direction then the camera moves towards left and if it moves in anti clockwise direction then the camera moves towards right.

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Operation principle of Navigation robot vehicle

In the base station we used keys to control the Robot these are connected to the 8051mc.The 8051mc takes commands from operator using keys and sending serial data to FM transmitter. The signal is frequency modulated with 100MHz carrier, which ultimately forms FSK. The signal is radiated using single Arial in to free space. The FM receiver receives the temperature feedback sent by the FM Tx at the vehicle section. The data received by the FM Rx is given to the micro controller (AT89C51) and from it to the LCD display, which displays the temperature. It is also used to display the commands at the same time its shows the temp. We used a TV, which has an in built AM Rx. It is used to show the location of robot with the help of camera at the vehicle section.

In the vehicle section, the FM receiver is constructed using TEA5710 I.C., which consists, RF amp, mixer, local oscillator, IF amplifiers, voltage limiters and demodulators. It receives the signals using single Arial and gives demodulated o/p. This o/p signal is further conditioned using LM324 op-amp. The o/p of the receiver is very low, so its level is amplified using differential amplifier. The o/p is fed to micro controller (AT89C51). The micro controller receives the serial data and accordingly drives the stepper motors. Here we used uni-polar stepper motors, which will have four windings. Each winding is driven with MOSFET (IRF540) for better switching and lesser power dissipation. The BC548 transistors are used to drive the MOSFET, because controller o/p is in the range of +5V and MOSFET is operating in the range of +12V. Full step mode is used for driving the stepper motor. In this mode, the rotating angle per step is 1.8º and torque is high. The gear ratio is 20:1 so in order to rotate the wheel one revolution, the stepper motor will have to move 20 revolutions. For one revolution of stepper motor we have to send 200 pulses i.e. 200 X 1.8º = 360º. So these operations are achieved using assembly level programming (ALP). The program is embedded permanently in to the flash memory of micro controller at the time of development.

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Block diagram and description The block diagram and its brief description of the project work are explained in block wise and this block diagram consists the following blocks. At The Transmitter End: 1. RF transmitter 2. RF Receiver 3. LCD Display 4. Power supply 5. Micro controller unit 6. TV At The Receiver End: 1. RF transmitter 2. AM transmitter 3. RF Receiver 4. Signal Amplifier 5. Micro controller unit 6. Motor driver 7. Temperature sensor 8. ADC 9. LDR sensor 10. Camera 11. Motors 12. Battery power supply

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Block diagram of vehicle control Section (transmitter section)

Keys

Micro controller

RF transmitter

TV

LCD Display

RF Rx

230V I/P

Power Supply

+5V

Block diagram of vehicle unit (receiver section)

RF RX

Micro Controller

Motor 1 Driver Motor 2 Driver Motor 3 Driver

MOT1 MOT2 MOT3

Amplifier

Unit 8051MC

RFTX ADC 808

Camera

AM TX LM 35

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Voltage regulator +12V +12V

Battery

Voltage regulator

+5V

Description of vehicle control Section
F.M. Transmitter This block generates a continuous frequency of 35MHz, which is used to form a permanent link between the transmitter and receiver, and this is known as carrier frequency. The output serial port is fed to this F.M radio transmitter. This is a frequency modulated radio transmitter. 20mw. The radiating power of the transmitter is

FM Receiver The FM receiver is designed with IC TEA5710, which is AM/FM Radio receiver IC, operates at a local oscillator of 88 - 108MHz and is tuned with the transmitter. This IC consists of built in RF amplifier, a double balanced mixer, local oscillator, a two stage IF amplifier, a quadrature demodulator for a ceramic filter and an automatic frequency control. The built in RF amplifier, a part from the amplification of received RF signal, it also reduces the Noise figure, which could other wise be a problem because of the large band widths needed for FM. It also matches the input impedance of the radio receiver with the antenna. . LCD Display Lcd display is used to display the temperature received from the FM RX and also it is used to display the movement of the keys. The Intersil ICL7106 are high performance, low power, 31/2 digit A/D converters. Included are seven segment

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decoders, display drivers, a reference, and a clock. The ICL7106 is designed to interface with a liquid crystal display (LCD) and includes a multiplexed back plane drive. The ICL7106 bring together a combination of high accuracy, versatility, and true economy. It features auto zero to less than 10μV, zero drift of less than 1μV/oC, input bias current of 10pA (Max), and rollover error of less than one count. True differential inputs and reference are useful in all systems, but give the designer an uncommon advantage When measuring load cells, strain gauges and other bridge type transducers. Finally, the true economy of single power supply operation (ICL7106) enables a high performance panel meter to be built with the addition of only 10 passive components and a display. Features • Guaranteed Zero Reading for 0V Input on All Scales • True Polarity at Zero for Precise Null Detection • 1pA Typical Input Current • True Differential Input and Reference, Direct Display Drive - LCD ICL7106 • Low Noise - Less Than 15μVP-P • On Chip Clock and Reference • Low Power Dissipation - Typically Less Than 10mW • No Additional Active Circuits Required • Enhanced Display Stability Power supply Power supply unit provides +5V & +9V regulated power to the system. It consists of two parts Rectifier and Monolithic IC voltage regulators. The o/p voltage of the battery is +12V so we give the supply of battery to regulators. The output voltage of the rectifier then regulated to +5V using LM7805 monolithic IC voltage regulators and the o/p voltage of LM7809 monolithic IC voltage regulators is regulated to +9V.

Description of vehicle unit

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F.M. Transmitter This block generates a continuous frequency of 45MHz, which is used to form a permanent link between the transmitter and receiver, and this is known as carrier frequency. The output serial port is fed to this F.M radio transmitter. This is a frequency modulated radio transmitter. The radiating power of the transmitter is 20mw.This is used to send the temperature from LM35, which is a temp sensor as o/p from LM35 is analog so we converted it to digital using ADC0808. FM Receiver The FM receiver is designed with IC TEA5710, which is AM/FM Radio receiver IC, operates at a local oscillator of 88 - 108MHz and is tuned with the transmitter. This IC consists of built in RF amplifier, a double balanced mixer, local oscillator, a two stage IF amplifier, a quadrature demodulator for a ceramic filter and an automatic frequency control. The built in RF amplifier, a part from the amplification of received RF signal, it also reduces the Noise figure, which could other wise be a problem because of the large band widths needed for FM. It also matches the input impedance of the radio receiver with the antenna. Signal Amplifier Here we are using a differential amplifier in series with a voltage follower constructed by using LM324 quad op-amps. The low level signal will be buffered and amplified to TTL level for input of micro controller. The LM324 series consists of four independent, high gains; internally frequency compensated operational amplifiers, which were designed specifically to operate from a single power supply over a wide range of voltages. Operation from split power supplies is also possible and the low power supply current drain is independent of the magnitude of the power supply voltage. Application areas include transducer amplifiers, DC gain blocks and all the conventional op amp circuits, which now can be more easily implemented in single power supply systems. For example, the LM324 series can be directly operated off of the standard +5V power supply voltage, which is used in digital systems and will easily

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provide the required Interface electronics without requiring the additional ±15V power supplies. Unique Characteristics • In the linear mode the input common-mode voltage Range includes ground and the output voltage can also • Swing to ground, even though operated from only a • Single power supply voltage • The unity gain cross frequency is temperature compensated • Eliminates need for dual supplies • Four internally compensated op amps in a single Package • Allows directly sensing near GND and VOUT also goes to GND • Compatible with all forms of logic • Power drain suitable for battery operation Features • Internally frequency compensated for unity gain • Large DC voltage gain 100 dB • Wide bandwidth (unity gain) 1 MHz (Temperature compensated) • Wide power supply range: Single supply 3V to 32V or dual supplies ±1.5V to ±16V • Very low supply current drain (700 µA)—essentially independent of supply voltage • Low input biasing current 45 nA (Temperature compensated) • Low input offset voltage 2 mV and offset current: 5 nA Temperature sensor The LM35 series are precision integrated-circuit temperature sensors, whose output voltage is linearly proportional to the Celsius (Centigrade) temperature. The LM35 thus has an advantage over linear temperature sensors calibrated in ß Kelvin, as the user is not required to subtract a large constant voltage from its output to obtain convenient Centigrade scaling. The LM35 does not require any external calibration or trimming to provide typical accuracies of g (/4ßC at room temperature and g*/4ßC over

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a full b55 to a150ßC temperature range. Low cost is assured by trimming and Calibration at the wafer level. The LM35's low output impedance, linear output, and precise inherent calibration make interfacing to readout or control circuitry especially easy. It can be used with single power supplies, or with plus and minus supplies. As it draws only 60 mA from its supply, it has very low self-heating, less than 0.1ßC in still air. The LM35 is rated to operate over a b55ß to a150ßC temperature range, while the LM35C is rated for a b40ß to a110ßC range (b10ß with improved accuracy). The LM35 series is available packaged in hermetic TO-46 transistor packages, while the LM35C, LM35CA, and LM35D are also available in the plastic TO-92 transistor package. The LM35D is also available in an 8-lead surface mount small outline package and a plastic TO-202 package. Features • Calibrated directly in ß Celsius (Centigrade) • Linear a 10.0 mV/ßC scale factor • 0.5ßC accuracy guarantee able (at a25ßC) • Rated for full b55ß to a150ßC range • Suitable for remote applications • Low cost due to wafer-level trimming • Operates from 4 to 30 volts • Less than 60 mA current drain • Low self-heating, 0.08ßC in still air • No linearity only g (/4ßC typical • Low impedance output, 0.1 X for 1 mA load Analog to digital converter (ADC) The ADC0808 is used to convert the analog output of the LM35 to digital output. The ADC0808 are monolithic CMOS devices with an 8-channel multiplexer, an 8-bit analog-to-digital (A/D) converter, and microprocessor-compatible control logic. The 8-channel multiplexer can be controlled by a microprocessor through a 3-bit address decoder with address load to select any one of eight single-ended analog switches connected directly to the comparator. The 8-bit A/D converter uses the

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successive-approximation conversion technique featuring a high-impedance threshold detector, a switched-capacitor array, a sample and- hold, and a successiveapproximation register (SAR). Detailed information on interfacing to most popular microprocessors is readily available from the factory. The comparison and converting methods used eliminate the possibility of missing codes, non monotonic, and the need for zero or full-scale adjustment. Also featured are latched 3-state outputs from the SAR and latched inputs to the multiplexer address decoder. The single 5-V supply and low power requirements make the ADC0808 especially useful for a wide variety of applications. Radiometric conversion is made possible by access to the reference voltage input terminals. The ADC0808 are characterized for operation from –40  to C 85C. Features • Total Unadjusted Error . . .  0.75 LSB Max for ADC0808 and  1.25 LSB Max for ADC0809 • Resolution of 8 Bits • 100- Conversion Time s • Radiometric Conversion • Monotonicity Over the Entire A/D Conversion Range • No Missing Codes • Easy interface with Microprocessors • Latched 3-State Outputs • Latched Address inputs • Single 5-V Supply • Low Power Consumption • Designed to Be Interchangeable With National Semiconductor ADC0808, ADC0809

Micro controller unit

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The AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4K bytes of Flash programmable and erasable read only memory (PEROM). The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set and pinout. The onchip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C51 is a powerful microcomputer, which provides a highly flexible and cost-effective solution to many embedded control applications. It consists of 128 bytes of RAM, 32 I/O lines, two 16-bittimer/counters, a five vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator and clock circuitry. In addition, the AT89C51 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue functioning. The Power-down Mode saves the RAM contents but freezes the oscillator disabling all other chip functions until the next hardware reset. Features • Compatible with MCS-51™ Products • 4K Bytes of In-System Reprogrammable Flash Memory – Endurance: 1,000 Write/Erase Cycles • Fully Static Operation: 0 Hz to 24 MHz • Three-level Program Memory Lock • 128 x 8-bit Internal RAM • 32 Programmable I/O Lines • Two 16-bit Timer/Counters • Six Interrupt Sources • Programmable Serial Channel • Low-power Idle and Power-down Modes

Motor driver

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For driving of motor coils, we used IRF540 MOSFET, which Utilize advanced processing techniques to achieve the lowest possible on-resistance per silicon area. This benefit, Combined with the fast switching speed and ruggedized device design that HEXFET Power MOSFETs are well Known for, provides the designer with an extremely efficient device for use in a wide variety of applications. It can operate up to a temperature up to 175°C Operating Temperature. This MOSFET is driven by BC548 transistor. For each motor four MOSFET sections are required.

Motors Unipolar stepper motors are used for moving the vehicle, because the driving circuit is simpler and yet it works well. It consists four windings and there are two driving methods are there. One is full step and other is half step. Full step moves 1.8º and half step moves 0.9º. The torque for full step driving is more compared to half step driving. Battery power supply A +12v, 7Ah Ni – cad, maintenance free battery is used to power the vehicle. The voltage of the battery is further regulated to +5V & +9V using LM7805 and LM7809 monolithic IC voltage regulators for I.C. operations.

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Navigation Robot Functional description of vehicle control section
F.M. Transmitter
12345

Fig – F.M. transmitter This block generates a continuous frequency of 35MHz, which is used to form a permanent link between the transmitter and receiver, and this is known as carrier frequency. The output of serial port is fed to this F.M radio transmitter. This is a frequency modulated radio transmitter. The radiating power of the transmitter is 20mw, and it is designed using BC 494 B high frequency switching transistor. This FM circuit uses a medium power VHF oscillator built around BF494 transistor. The instantaneous frequency of the carrier is varied directly in accordance with the base band signal by means of a device known as VCO (Voltage Controlled Oscillator) one of implementing such a device is to use to sinusoidal oscillator having a relatively high-Q frequency. modulated at 100MHz carrier. A varicap-based circuit is used for good quality frequency modulation. By varying variable capacitor (trimmer) or by adjusting spacing of coil L1 can alter operating frequency. Coil L1 consists of five turns of 20 SWG wire, space wound air core. Antenna tap is taken at one turn from bottom end. By using 70cm single wire Ariel, range of up to 50 fts may be expected. Using a multi-element ground plane antenna can extend the range. Length of each pole is 70 cms for 100MHz frequency. Determining Network and to control the oscillator by symmetrical incremental variation of the reactive components. Thus the serial data is

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Vertical pole is the active radiator. All radials are shorted and connected to ground of PCB. Power supply

Fig – power supply Power supply unit provides 5V regulates power supply to the systems. It consists of two parts namely, 1. Rectifier 2. Monolithic voltage regulator Rectifier Here the step down transformer 230-0v/9-0-9 and gives the secondary current up to 500mA, to the Rectifier. The Transformer secondary is provided with a center tap. Hence the voltage V1 and V2 are equal and are having a phase difference of 180 0. So it is anode of Diode D1 is positive with respect to the center tap, the anode of the other diode d2 will be negative with respect to the center tap. During the positive half cycle of the supply D1 conduct’s and current flows through the center tap D1 and load. During this period D2 will not conduct as its anode is at a negative potential. During the negative half cycle of the supply voltage, the voltage on the diode D2 will be positive and hence D2 conducts. The current flows through the transformer winding, Diode D2 and load. It is to be noted that the current i1 and i2 are flowing in the same direction in load. The average of the two current i1 and i2 flows through the load producing a voltage drop, which is the D.C. output voltage of the rectifier. Using capacitor filters

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the ripple in the out waveform can be minimized. The voltage can be regulated by using monolithic IC voltage regulators. Monolithic IC voltage regulator: A voltage regulator is a circuit that supplies a constant voltage regardless of changes in load currents. Although voltage regulators can be designed using op-amps, it is quicker and easier to use IC voltage regulators. Furthermore, IC voltage regulators are versatile and relatively inexpensive and are available with features such as programmable output, current/voltage boosting, internal short-circuit current limiting, thermal shutdown and floating operation for high voltage applications Here we are using 7800 series voltage regulators. The 7800 series consists of 3terminal +ve voltage regulators with seven voltage options. These ICs are designed as fixed voltage regulators and with adequate heat sinking can deliver output currents in excess of 1A. Although these devices do not require external components, such components can be used to obtain adjustable voltages and currents. For proper operation a common ground between input and output voltages is required. In addition, the difference between input and output voltages (Vi – Vo) called drop out voltage, must be typically 1.5V even during the low point as the input ripple voltage. Further more, the capacitor Ci is required if the regulator is located an appreciable distance from a power supply filter. Even though Co is not needed, it may be used to improve the transient response of the regulator. Typical performance parameters for voltage regulators are line regulation, load regulation, temperature stability and ripple rejection. Line regulation is defined as the change in output voltage for a change in the input voltage and is usually expressed in milli volts or as a percentage of Vo. Temperature stability or average temperature coefficient of output voltage (TCVo) is the change in output voltage per unit change in temperature and is expressed in either milli volts/ºC or parts per million (PPM/ºC). Ripple rejection is the measure of a regulator’s ability to reject ripple voltage. It is usually expressed in decibels. The smaller the values of line regulation, load regulation and temperature stability the better the regulation.

Functional description of vehicle unit
FM Receiver

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The FM receiver is designed with IC CXA1619BM/BS, which is AM/FM Radio receiver IC, operates at a local oscillator of 88 - 108MHz and is tuned with the transmitter. This IC consists of built in RF amplifier, a double balanced mixer, local oscillator, a two stage IF amplifier, a quadrature demodulator for a ceramic filter and an automatic frequency control. The built in RF amplifier, a part from the amplification of received RF signal, it also reduces the Noise figure, which could other wise be a problem because of the large band widths needed for FM. It also matches the input impedance of the radio receiver with the antenna Signal buffer and level converter

Fig – signal buffer In the first stage the output of the op-amp is connected directly to inverting input so that it acts as a voltage follower or buffer. This will prevent any loading of signal by the next stage. In the second stage a variable voltage reference is connected to non-inverting input and signal is connected to inverting input. If the signal is lower then the reference the output will go high (+5V), or if the signal is higher then the reference then the output goes low (0V). Normally the signal level will be 2V for low and 2.5V for high. After comparator the output will be 0V for high input and +5Vfor low input i.e. the level is converted. AM Transmitter

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This circuit is deliberately limited in power output but will provide amplitude modulation (AM) of picture over the medium wave band. The circuit is in two half’s, an audio amplifier and an RF oscillator. The oscillator is built around Q1 and associated components. The tank circuit L1 and VC1 is tunable from about 500kHz to 1600KHz.. Q1 needs regenerative feedback to oscillate and this is achieved by connecting the base and collector of Q1 to opposite ends of the tank circuit. The 1nF capacitor C7, couples signals from the base to the top of L1, and C2, 100pF ensures that the oscillation is passed from collector, to the emitter, and via the internal base emitter resistance of the transistor, back to the base again. Resistor R2 has an important role in this circuit. It ensures that the oscillation will not be shunted to ground via the very low internal emitter resistance, re of Q1, and also increases the input impedance so that the modulation signal will not be shunted. Oscillation frequency is adjusted with VC1. Q2 is wired as a common emitter amplifier, C5 decoupling the emitter resistor and realising full gain of this stage. The microphone is an electrets condenser mic and

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the amount of AM modulation is adjusted with the 4.7k preset resistors P1. An antenna is not needed, but 30cm of wire may be used at the collector to increase transmitter range. Bit micro controller The Micro controller is used for interface with FM receiver and stepper motors and it gives proper stepping pulses for vehicle movements, by receiving serial data from FM receiver.

Introduction Looking back into the history of microcomputers, one would at first come across the development of microprocessor i.e. the processing element, and later on the peripheral devices. The three basic elements-the CPU, I/O devices and memory-have developed in distinct directions. While the CPU has been the proprietary item, the memory devices fall into general-purpose category and the I/O devices may be grouped somewhere in-between. The AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4K bytes of Flash programmable and erasable read only memory (PEROM). The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set and pinout. The onchip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C51 is a powerful microcomputer, which provides a highly flexible and cost-effective solution to many embedded control applications. The AT89C51 provides for 4k EPROM/ROM, 128 byte RAM and 32 I/O lines. It also includes a universal asynchronous receive-transmit (UART) device, two 16-bit timer/counters and elaborate interrupt logic. Lack of multiply and divide instructions which had been always felt in 8-bit microprocessors/micro controllers, has also been taken care of in the 89C51- Thus the 89C51 may be called nearly equivalent of the following devices on a single chip: 8085 + 8255 + 8251 + 8253 + 2764 + 6116. In short, the AT89C51 has the following on-chip facilities:

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 4k ROM (EPROM on 8751)  128 byte RAM  UART  32 input-output port lines  Two, 16-bit timer/counters  Six interrupt sources and  On-chip clock oscillator and power on reset circuitry

Pin Description Of 8051

Pin Diagram

VCC Supply voltage. GND Ground. Port 0 Port 0 is an 8-bit open-drain bi-directional I/O port. As an output port, each pin can sink eight TTL inputs. When 1sare written to port 0 pins, the pins can be used as high impedance inputs. Port 0 may also be configured to be the multiplexed low order address/data bus during accesses to external program and data memory. In this mode P0

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has internal pull-ups. 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 bi-directional I/O port with internal pull-ups. The Port 1 output buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins they are pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 1 pins that are externally being pulled low will source current (IIL) because of the internal pull-ups. Port 1 also receives the low-order address bytes during Flash programming and verification.

Port 2 Port 2 is an 8-bit bi-directional I/O port with internal pull-ups. The Port 2 output buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins they are pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 2 pins that are externally being pulled low will source current (IIL) because of the internal pull-ups. Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16-bit addresses (MOVX @DPTR). In this application, it uses strong internal pull-ups when emitting 1s. During accesses to external data memory that use 8-bit addresses (MOVX @ RI), Port 2 emits the contents of the P2 Special Function Register. Port 2 also receives the high-order address bits and some control signals during Flash programming and verification.

Port 3 Port 3 is an 8-bit bi-directional I/O port with internal pull-ups. The Port 3 output buffers can sink/source four TTL inputs. When 1s are written to Port 3 pins they are pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 3 pins that are serves the functions of various special features of the AT89C51 as listed below:

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Port 3 also receives some control signals for Flash programming and verification. 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 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. Note, however, that one ALE pulse is skipped during each access to external Data Memory. If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has no effect if the micro controller is in external execution mode.

PSEN Program Store Enable is the read strobe to external program memory. When the AT89C51 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.

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EA/VPP EA is called as 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, for parts that require 12-volt VPP. XTAL1 Input to the inverting oscillator amplifier and input to the internal clock operating circuit. XTAL2 This is an Output from the inverting oscillator amplifier.

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Internal Block diagram

Fig – AT89C51 internal block diagram Silent features The 89C51 can be configured to bypass, the internal 4k ROM and run solely with external program memory. For this its external access (EA) pin has to be grounded, which makes it equivalent to 8031. The program store enable (PSEN) signal acts as read pulse for program memory. The data memory is external only and a separate RD* signal is available for reading its contents. Use of external memory requires that three of its 8-bit ports (out of four) be configured to provide data/address multiplexed bus. Hi address bus and control signals related to external memory use. The RXD and TXD ports of UART also appear on pins

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10 and 11 of 8051 and 8031, respectively. One 8-bit port, which is bit addressable and, extremely useful for control applications. The UART utilizes one of the internal timers for generation of baud rate. The crystal used for generation of CPU clock has therefore to be chosen carefully. The 11.0596 MHz crystals; available abundantly, can provide a baud rate of 9600. The 256-byte address space is utilized by the internal RAM and special function registers (SFRs) array, which is separate from external data RAM space of 64k. The 00-7F space is occupied by the RAM and the 80 - FF space by the SFRs. The 128 byte internal RAM has been utilized in the following fashion: 00-IF: Used for four banks of eight registers of 8-bit each. The four banks may be selected by software any time during the program.  20-2F: The 16 bytes may be used as 128 bits of individually addressable locations. These are extremely useful for bit-oriented programs.  30- 7F: This area is used for temporary storage, pointers and stack. On reset, the stack starts at 08 and gets incremented during use.  The list of special function registers along with their hex addresses is given Table 5.3 AT89C51 Address register Addr. Port/Register 80 P0 (Port 0) 81 SP (stack pointer) 82 DPH (data pointer High) 83 DPL (data pointer Low) 88 TCON (timer control) 89 TMOD (timer mode) 8A TLO (timer 0 low byte) 8B TL1 (timer 1 low byte) 8C TH0 (timer 0 high byte) 8D TH1 (timer 1 high byte) 90 P1 (port 1) 98 SCON (serial control) 99 SBUF (serial buffer) A0 P2 (port 2) A8 Interrupt enable (IE) B0 P3 (port 3) B8 Interrupt priority (IP) D0 Processor status word (PSW) E0 Accumulator (ACC) F0 B register Table– AT89C51 SFR

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Hardware details The on chip oscillator of 89C51 can be used to generate system clock. Depending upon version of the device, crystals from 3.5 to 12 MHz may be used for this purpose. The system clock is internally divided by 6 and the resultant time period becomes one processor cycle. The instructions take mostly one or two processor cycles to execute, and very occasionally three processor cycles. The ALE (address latch enable) pulse rate is 16th of the system clock, except during access of internal program memory, and thus can be used for timing purposes. AT89C51 Serial port pins PIN P3.ORXD P3.ITXD P3.2INTO P3.3INT1 P3.4TO P3.5T1 P3.6WR P3.7RD ALTERNATE USE Serial data input Serial data output External interrupt 0 External interrupt 1 External timer 0 input External timer 1 input External memory write pulse External memory read pulse Table – AT89C51 serial port pins SFR SBUF SBUF TCON-1 TCON- 2 TMOD TMOD ------------

The two internal timers are wired to the system clock and prescaling factor is decided by the software, apart from the count stored in the two bytes of the timer control registers. One of the counters, as mentioned earlier, is used for generation of baud rate clock for the UART. It would be of interest to know that the 8052 have a third timer, which is usually used for generation of baud rate. The reset input is normally low and taking it high resets the micro controller, in the present hardware, a separate CMOS circuit has been used for generation of reset signal so that it could be used to drive external devices as well. Writing the software The 89C51 has been specifically developed for control applications. As mentioned earlier, out of the 128 bytes of internal RAM, 16 bytes have been organized

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in such a way that all the 128 bits associated with this group may be accessed bit wise to facilitate their use for bit set/reset/test applications. These are therefore extremely useful for programs involving individual logical operations. One can easily give example of lift for one such application where each one of the floors, door condition, etc may be depicted by a single hit. The 89C51 has instructions for bit manipulation and testing. Apart from these, it has 8-bit multiply and divide instructions, which may be used with advantage. The 89C51 has short branch instructions for 'within page' and conditional jumps, short jumps and calls within 2k memory space which are very convenient, and as such the controller seems to favor programs which are less than 2k byte long. Some versions of 8751 EPROM devices have a security bit which can be programmed to lock the device and then the contents of internal program EPROM cannot be read. The device has to be erased in full for further alteration, and thus it can only be reused but not copied. EEPROM and FLASH memory versions of the device are also available now. The term used in micro controller is: Memory unit Memory is part of the micro controller whose function is to store data. The easiest way to explain it is to describe it as one big closet with lots of drawers. If we suppose that we marked the drawers in such a way that they cannot be confused, any of their contents will then be easily accessible. It is enough to know the designation of the drawer and so its contents will be known to us for sure. Memory components are exactly like that. For a certain input we get the contents of a certain addressed memory location and that’s all. Two new concepts are brought to us: addressing and memory location. Memory consists of all memory locations, and addressing is nothing but selecting one of them. This means that we need to select the desired memory location on one hand, and on the other hand we need to wait for the contents of that location. Besides reading from a memory location, memory must also provide for writing onto it. This is done by supplying an additional line, called control line. We will designate this line as R/W (read/write). Control line is used in the following way: if r/w=1, reading is done, and if opposite is true then writing is done on the memory location. Memory is the first element, and we need a few operation of our micro controller.

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Central Processing Unit Let add 3 more memory locations to a specific block that will have a built in capability to multiply, divide, subtract, and move its contents from one memory location onto another. The part we just added in is called “central processing unit” (CPU). Its memory locations are called registers. Registers are therefore memory locations whose role is to help with performing various mathematical operations or any other operations with data wherever data can be found. Look at the current situation. We have two independent entities (memory and CPU), which are interconnected, and thus any exchange of data is hindered, as well as its functionality. If, for example, we wish to add the contents of two memory locations and return the result again back to memory, we would need a connection between memory and CPU. Simply stated, we must have some “way” through data goes from one block to another. Bus That “way” is called “bus”. Physically, it represents a group of 8, 16, or more wires. There are two types of buses: address and data bus. The first one consists of as many lines as the amount of memory we wish to address, and the other one is as wide as data, in our case 8 bits or the connection line. First one serves to transmit address from CPU memory, and the second to connect all blocks inside the micro controller. Input-output unit Those locations we’ve just added are called “ports”. There are several types of ports: input, output or bi-directional ports. When working with ports, first of all it is necessary to choose which port we need to work with, and then to send data to, or take it from the port. When working with it the port acts like a memory location. Something is simply being written into or read from it, and it could be noticed on the pins of the micro-controller.

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Stepper Motor drives

Fig – stepper motor drive circuit When the output of the controller is high, the base current Iв flows in to base of the transistor, thus providing voltage drop more then 0.7V across the Vвe junction, thus the transistor goes in to saturation mode. So the Ic is maximum and the voltage drop across the Vce junction is zero. I.e. the input to MOSFET is zero. So the MOSFET will not conduct and stepper motor coil will not energize. If the output of the controller is low, the base current Iв is zero, thus providing voltage drop less then 0.1V across the Vвe junction, thus the transistor goes in to cutoff mode. So the Ic is minimum and the voltage drop across the Vce junction is maximum. I.e. the input to MOSFET is almost Vcc. So the MOSFET will conduct and stepper motor coil get energized. Is For driving of motor coils, we used IRF540 MOSFET, which are having low onstate resistance so that the dissipation is less, fast switching and low thermal resistance. This MOSFET is driven by BC548 transistor. For each motor four MOSFET sections are required.

Stepper motors
Introduction Stepper Motors have several features, which distinguish them from AC Motors, and DC Servo Motors.

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 Brush less - Steppers are brush less Motor with contact brushes creates sparks, undesirable in certain environments. (Space missions, for example.)  Holding Torque - Steppers have very good low speed and holding torque. Steppers are usually rated in terms of their holding force (oz/in) and can even hold a position (to a lesser degree) without power applied, using magnetic 'detent' torque.  Open loop positioning - Perhaps the most valuable and interesting feature of a stepper is the ability to position the shaft in fine predictable increments, without need to query the motor as to its position. Steppers can run 'open-loop' without the need for any kind of encoder to determine the shaft position. Closed loop systemssystems that feed back position information, are known as servo systems. Compared to servos, steppers are very easy to control; the position of the shaft is guaranteed as long as the torque of the motor is sufficient for the load, under all its operating conditions.  Load Independent - The rotation speed of a stepper is independent of load, provided it has sufficient torque to overcome slipping. The higher rpm a stepper motor is driven, the more torque it needs, and so all steppers eventually poop out at some rpm and start slipping. Slipping is usually a disaster for steppers, because the position of the shaft becomes unknown. For this reason, software usually keeps the stepping rate within a maximum top rate. In applications where a known RPM is needed under a varying load, steppers can be very handy.

Types of stepper Motors Stepper Motors come in a variety of sizes, and strengths, from tiny floppy disk motors, to huge machinery steppers rated over 1000 oz in. There are two basic types of steppers-- bipolar and unipolar. The bipolar stepper has 4 wires. Unipolar steppers have 5,6 or 8 wires. This document will discuss control of Unipolar Steppers. Motor Basics

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The Unipolar Stepper motor has 2 coils, simple lengths of wound wire. The coils are identical and are not electrically connected. Each coil has a center tap - a wire coming out from the coil that is midway in length between its two terminals. You can identify the separate coils by touching the terminal wires together-- If the terminals of a coil are connected, the shaft becomes harder to turn. Because of the long length of the wound wire, it has a significant resistance (and inductance). You can identify the center tap by measuring resistance with a suitable ohm-meter (capable of measuring low resistance <10 ohm) The resistance from a terminal to the center tap is half the resistance from the two terminals of a coil. Coil resistance of half a coil is usually stamped on the motor; For example, '5 ohms/phase' indicates the resistance from center tap to either terminal of a coil. The resistance from terminal to terminal should be 10 ohms.

Fig – stepper motor coil diagram Motor Control Circuitry

Fig – magnetic field diagram Current flowing through a coil produces a magnet field, which attracts a permanent magnet rotor, which is connected to the shaft of the motor. The basic principle of stepper control is to reverse the direction of current through the 2 coils of a stepper motor, in sequence, in order to influence the rotor. Since there are 2 coils and 2 directions, that gives us a possible 4-phase sequence. All we need to do is get the sequencing right and the motor will turn continuously. You may wonder how the stepper can achieve such fine stepping increments with only a 4-phase sequence. The

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internal arrangement of the motor is quite complex- the winding and core repeating around the perimeter of the motor many times. The rotor is advanced only a small angle, either forward or reverse, and the 4-phase sequence is repeated many times before a complete revolution occurs.

Fig – stepper motor basic control diagram Let us return to the 4-phase sequence of reversing the current though the 2 coils. A Bipolar stepper controller achieves the current reversal by reversing the polarity at the two terminals of a coil. The Unipolar controller takes advantage of the center tap to achieve the current reversal with a clever trick -- The Center tap is tied to the positive supply, and one of the 2 terminals is grounded to get the current flowing one direction. The other terminal is grounded to reverse the current. Current can thus flow in both directions, but only half coils are energized at a time. Both terminals are never grounded at the same time, which would energize both coils, achieving nothing but a waste of power.

Conceptual Model of Unipolar Stepper Motor

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Fig– conceptual model of unipolar stepper motor With center taps of the windings wired to the positive supply, the terminals of each winding are grounded, in sequence, to attract the rotor, which is indicated by the arrow in the picture. (Remember that a current through a coil produces a magnetic field.) This conceptual diagram depicts a 90-degree step per phase. In a basic "Wave Drive" clockwise sequence, winding 1a is de-activated and winding 2a activated to advance to the next phase. The rotor is guided in this manner from one winding to the next, producing a continuous cycle. Note that if two adjacent windings are activated, the rotor is attracted mid-way between the two windings. The following table describes 3 useful stepping sequences and their relative merits. The sequence pattern is represented with 4 bits; a '1' indicates an energized winding. After the last step in each sequence the sequence repeats. Stepping backwards through the sequence reverses the direction of the motor.

Table of Stepping Sequences

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Sequence 0001 0010 0100 1000 0011 0110 1100 1001 0001 0011 0010 0110 0100 1100 1000 1001 Name Wave Drive, OnePhase HiTorque, TwoPhase Half-Step Half Step - Effectively doubles the stepping resolution of the motor, but the torque is not uniform for each step. (Since we are effectively switching between Wave Drive and Hi-Torque with each step, torque alternates each step.) This sequence reduces motor resonance, which can sometimes cause a motor to stall at a particular resonant frequency. Note that this sequence is 8 steps. Table– Table of stepping sequences Hi Torque - This sequence energizes two adjacent phases, which offers an improved torque-speed product and greater holding torque. Description Consumes the least power. Only one phase is energized at a time. Assures positional accuracy regardless of any winding imbalance in the motor.

Identifying Stepper Motors

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Fig– stepper motor identification diagram Stepper motors have numerous wires, 4, 5, 6, or 8. When you turn the shaft you will usually feel a "notched" movement. Motors with 4 wires are probably bipolar motors and will not work with a unipolar control circuit. The most common configurations are pictured above. You can use an ohmmeter to find the center tap - the resistance between the center and a leg is 1/2 that from leg to leg. Measuring from one coil to the other will show an open circuit, since the 2 coils are not connected. (Notice that if you touch all the wires together, with power off, the shaft is difficult to turn!) Shortcut for finding the proper wiring sequence Connect the center tap(s) to the power source (or current-Limiting resistor.) Connect the remaining 4 wires in any pattern. If it doesn't work, you only need try these 2 swaps... 1 1 1 2 2 8 4 8 2 8 4 4 (arbitrary switch first end wiring order) pair

switch middle pair

You're finished when the motor turns smoothly in either direction. If the motor turns in the opposite direction from desired, reverse the wires so that ABCD would become DCBA.

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Heat Considerations Over-heating can be an early indicator of a problem or need for additional heat sinking. This is true of both the controller and motors. Components can be warm to the touch, but not so hot that you can't leave your finger on them for a few seconds. Motors are designed to be mounted in such a way that, heat is drawn away from the motors. This is usually accomplished with a metal mounting bracket. Motors that are not yet mounted may require some type of temporary heat sinking. Motors heat more running at the LOW speeds or in Hold Mode. If a component or motor is running too hot, try using the Wave Drive stepping mode only, if it still runs too hot, try heat sinking, and/or a fan. If it still runs too hot, something is wrong. Battery power supply LM7805 C1 IN OUT GND C3 +5V

BATTERY +12V

Fig battery power supply A +12v, 7Ah Ni – cad, maintenance free battery is used to power the vehicle. The voltage of the battery is further regulated to +5V using LM7805 monolithic IC voltage regulators for I.C. operations as described

SOFTWARE ASSEMBLE SECTION
; ;> ;> TITLE ;> TARGET

LANGUAGE–PROGRAM

FOR

CONTROL

: NAVIGATION ROBOT : AT89C51

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;> VERSION : VER-01 ;> STARTED : 15-01-2006 ;> ; ;> ;> INCLUDES : $MOD51 ;> ; ;> ;> HARD WARE DETAILS : ;> MOTOR CONTROL 1 - P0.0 TO P0.3 ;> MOTOR CONTROL 2 - P0.4 TO P0.7 ;> MOTOR CONTROL 3 - P2.0 TO P2.3 ;> LIGHT CONTROL - P3.3 LCTR BIT P3.3 ;> A0 OF ADC - P3.7 A0 BIT P3.7 ;> ALE OF ADC - P3.6 ALE BIT P3.6 ;> SOC OF ADC - P3.4 SOC BIT P3.4 ;> EOC OF ADC - P3.5 EOC BIT P3.5 ;> ; ;> ;> FLAGS : KEY_RLS BIT 00H ;> ; ;> ;> VARIABLES : COMMAND DATA 30H STEP_CNT DATA 31H ADC_VAL DATA 32H TMR_VAL1 DATA 33H TMR_VAL2 DATA 34H TMP_VAL DATA 35H CHK_SUM DATA 36H ;> ; ;> ;> VECTOR ADDRESESS: ORG 0000H ljmp INITIALISATION ORG 000BH push ACC push PSW ; T0 interrupt

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lcall T0INT pop PSW pop ACC reti ORG 0023H push ACC push PSW ; SERIAL INTERRUPT

jbc RI, RECEIVE_DATA ajmp SKIP_CHKS RECEIVE_DATA: mov A, SBUF cjne A, #55H, CHEK_NEXT0 mov R0, #00H cpl P2.0 setb P2.2 ljmp SKIP_CHKS CHEK_NEXT0: cjne R0, #00H, CHEK_NEXT1 cjne A, #0AAH, CHEK_NEXT1 mov R0, #01H ljmp SKIP_CHKS CHEK_NEXT1: cjne R0, #01H, CHEK_NEXT2 mov R0, #02H mov TMP_VAL, A ljmp SKIP_CHKS CHEK_NEXT2: cjne R0, #02H, SKIP_CHKS mov R0, #00H mov CHK_SUM, A mov A, #0AAH xrl A, TMP_VAL cjne A, CHK_SUM, SKIP_CHKS mov COMMAND, TMP_VAL cpl P2.2 SKIP_CHKS: pop PSW pop ACC reti ;> ; ;> INITIALISATION: mov P0, #0FFH mov P1, #0FFH

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mov P2, #0FFH mov P3, #0FFH mov SP, #65H mov DPTR, #0400H anl PCON, #7FH ; CLR SMOD BIT mov TMOD, #21H ; TIMER 1 IN MODE 2, TIMER 0 IN MODE 1 mov TH1, #0E7H ; SET BAUD RATE AS 1200 mov SCON, #50H ; SERIAL MODE 1 AND RECEIVE ENABLE mov IE, #92H ; ENABLE SERIAL INTERRUPT & TIMER 0 INTERRUPT setb TR1 ; RUN TIMER 1 mov TMR_VAL2, #0E8H mov TMR_VAL1, #00H mov TH0, #0EDH mov TL0, #0FFH setb TR0 ; RUN TIMER 0 mov STEP_CNT, #00h mov COMMAND, #'0' ;> ; ;> MAIN: clr A0 lcall READ_ADC mov SBUF, #055H CHAN0: jnb TI, CHAN0 clr TI lcall SERL_DLY1 mov SBUF, #0AAH CHAN1: jnb TI, CHAN1 clr TI lcall SERL_DLY1 mov SBUF, ADC_VAL CHAN2: jnb TI, CHAN2 clr TI lcall SERL_DLY1 mov A, #0AAH xrl A, ADC_VAL mov SBUF, A CHAN3: jnb TI, CHAN3 clr TI ; AA IS HEADER FOR TEMPERATURE ; AA IS HEADER FOR TEMPERATURE

; CALUCLATE CHEK SUM

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lcall SERL_DLY setb A0 lcall READ_ADC mov A, ADC_VAL cjne A, #0B0H, CHEK_LIGHT CHEK_LIGHT: jc SWITCHON_LIGHT setb LCTR SWITCHON_LIGHT: jnc SWITCHOFF_LIGHT clr LCTR SWITCHOFF_LIGHT: ljmp MAIN ;> ; ;> T0INT: mov A, COMMAND cjne A, #'1', SKIP_FOR_MOVE mov DPTR, #STEP_RUN orl P2, #0F0H lcall MOVE_FRWD ajmp SKIP_OFF_MOT SKIP_FOR_MOVE: mov A, COMMAND cjne A, #'2', SKIP_REV_MOVE mov DPTR, #STEP_RUN orl P2, #0F0H lcall MOVE_REV ajmp SKIP_OFF_MOT SKIP_REV_MOVE: mov A, COMMAND cjne A, #'3', SKIP_LEFT_MOVE mov DPTR, #STEP_LEFT orl P2, #0F0H lcall MOVE_LEFT ajmp SKIP_OFF_MOT SKIP_LEFT_MOVE: mov A, COMMAND cjne A, #'4', SKIP_RIGHT_MOVE mov DPTR, #STEP_RIGHT orl P2, #0F0H lcall MOVE_RIGHT ajmp SKIP_OFF_MOT SKIP_RIGHT_MOVE: mov A, COMMAND cjne A, #'5', SKIP_CW_MOVE inc TMR_VAL1 mov R1, TMR_VAL1

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cjne R1, #02H, SIP_OF_MO mov TMR_VAL1, #00H mov DPTR, #STEP_GUN mov P0, #0FFH lcall MOVE_CW SIP_OF_MO: ajmp SKIP_OFF_MOT SKIP_CW_MOVE: mov A, COMMAND cjne A, #'6', SKIP_CCW_MOVE inc TMR_VAL1 mov R1, TMR_VAL1 cjne R1, #02H, SKIP_OFF_MOT mov TMR_VAL1, #00H mov DPTR, #STEP_GUN mov P0, #0FFH lcall MOVE_CCW ajmp SKIP_OFF_MOT SKIP_CCW_MOVE: mov A, COMMAND cjne A, #'7', SKIP_OFF_MOT SKIP_OFF_MOT: mov A, COMMAND cjne A, #'8', SKIP_OFF_MOT1 mov P0, #0FFH orl P2, #0FFH SKIP_OFF_MOT1: mov TH0, #0B6H mov TL0, #03BH ret ;> ; ;> MOVE_FRWD: mov A, STEP_CNT movc A, @A+dptr mov P0, A inc STEP_CNT mov A, STEP_CNT cjne A, #04h, NOTCH1 mov STEP_CNT, #00h NOTCH1: ret ;> ; ;> MOVE_REV: mov A, STEP_CNT movc A, @A+dptr mov P0, A

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dec STEP_CNT mov A, STEP_CNT cjne A, #0FFh, NOTCH4 mov STEP_CNT, #03h NOTCH4: ret ;> ; ;> MOVE_LEFT: mov A, STEP_CNT movc A, @A+dptr mov P0, A inc STEP_CNT mov A, STEP_CNT cjne A, #08h, NOTCH2 mov STEP_CNT, #00h NOTCH2: ret ;> ; ;> MOVE_RIGHT: mov A, STEP_CNT movc A, @A+dptr mov P0, A inc STEP_CNT mov A, STEP_CNT cjne A, #08h, NOTCH3 mov STEP_CNT, #00h NOTCH3: ret ;> ; ;> MOVE_CW: mov A, STEP_CNT movc A, @A+dptr mov R7, A mov A, P2 anl A, #0FH orl A, R7 mov P2, A inc STEP_CNT mov A, STEP_CNT cjne A, #04h, NOTCH7 mov STEP_CNT, #00h NOTCH7: ret ;>

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; ;> MOVE_CCW: mov A, STEP_CNT movc A, @A+dptr mov R7, A mov A, P2 anl A, #0FH orl A, R7 mov P2, A dec STEP_CNT mov A, STEP_CNT cjne A, #0FFh, NOTCH8 mov STEP_CNT, #03h NOTCH8: ret ;> ; ;> ; ADC reading function READ_ADC: setb ALE lcall CLK_DLY setb SOC lcall CLK_DLY clr ALE lcall CLK_DLY clr SOC lcall CLK_DLY EOC_LOOP: jnb EOC, EOC_LOOP lcall ADC_DLY nop nop mov ADC_VAL, P1 nop RET ;> ; ;> ; software delay loops ADC_DLY: mov R7, #7FH AIN: djnz R7, AIN RET ;> ; ;> ; software delay loops CLK_DLY:

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mov R7, #1FH CIN: djnz R7, CIN RET ;> ; ;> SERL_DLY: mov R6, #10H SOUT: mov R7, #00H SIN: djnz R7, SIN djnz R6, SOUT RET ;> ; ;> SERL_DLY1: mov R6, #05H SOUT1: mov R7, #10H SIN1: djnz R7, SIN1 djnz R6, SOUT1 RET ;> ; ;> DELAY: mov R7, #2d EXT: mov R6, #10d IN: mov R5, #30d OUT: djnz R5, OUT djnz R6, IN djnz R7, EXT ret ;> ; ;> ORG 0400H STEP_RUN: db 9AH db 56H db 65H db 0A9H STEP_LEFT: db 051H db 069H db 0A8H db 09AH db 052H db 066H

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db db 0A4H 095H

STEP_RIGHT: db 5AH db 46H db 65H db 29H db 0AAH db 86H db 95H db 19H STEP_GUN: db 090H db 050H db 060H db 0A0H END

PROGRAM FOR VEHICLE SECTION
; ;> ;> TITLE : NAVIGATION ROBOT TRANSMITTER ;> TARGET : AT89C51 ;> STARTED : 15-01-2006 ;> ; ;> ;> INCLUDES : $MOD51 ;> ; ;> ;> HARD WARE DETAILS : ;> ;> DISPLAY ENEBLE - P3.5 DEN BIT P3.5 ;> DISPLAY READ/WRITE - P3.6 DRW BIT P3.6 ;> DISPLAY REG SELECT - P3.7 DRS BIT P3.7 ;> KEY INPUT 1 - P1.0 KEY1 BIT P1.0 ;> KEY INPUT 2 - P1.1 KEY2 BIT P1.1 ;> KEY INPUT 3 - P1.2 KEY3 BIT P1.2 ;> KEY INPUT 4 - P1.3 KEY4 BIT P1.3 ;> KEY INPUT 5 - P1.4

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;> ;> ;> ;> ;> ; ;> ;> KEY5 BIT P1.4 KEY INPUT 6 - P1.5 KEY6 BIT P1.5 KEY INPUT 7 - P1.6 KEY7 BIT P1.6 KEY INPUT 8 - P1.7 KEY8 BIT P1.7 TRANSMITTER CONTROL TXC BIT P3.3

- P3.3

FLAGS : BUSY_CHEK BIT 00H KEY_RLS BIT 01H SERL_INT BIT 02H READ_TMP BIT 03H

;> ; ;> ;>

VARIABLES : KEY_PRS DATA 30H TMP_VAL DATA 31H CHK_SUM DATA 32H ADC_VAL DATA 33H TMPR_VAL DATA 34H TMPR_VAH DATA 35H

;> ; ;> ;> ;>

DEFINITIONS COM DAT EOL

: EQU 0fch EQU 0fdh EQU 0feh ; command ; data ; end of line ;display headers

;> ; ;> ;>

VECTOR ADDRESESS: ORG 0000H ljmp RESET ORG 0023H push ACC push PSW ; SERIAL INTERRUPT

jbc RI, RECEIVE_DATA ajmp SKIP_CHKS RECEIVE_DATA:

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mov A, SBUF cjne A, #55H, CHEK_NEXT0 setb READ_TMP mov R0, #00H ljmp SKIP_CHKS CHEK_NEXT0: cjne R0, #00H, CHEK_NEXT1 cjne A, #0AAH, CHEK_NEXT1 mov R0, #01H ljmp SKIP_CHKS CHEK_NEXT1: cjne R0, #01H, CHEK_NEXT2 mov R0, #02H mov TMP_VAL, A ljmp SKIP_CHKS CHEK_NEXT2: cjne R0, #02H, SKIP_CHKS mov R0, #00H mov CHK_SUM, A mov A, #0AAH xrl A, TMP_VAL cjne A, CHK_SUM, SKIP_CHKS mov ADC_VAL, TMP_VAL setb SERL_INT clr READ_TMP SKIP_CHKS: pop PSW pop ACC reti ;> ; ;> RESET: mov mov mov mov mov clr lcall mov lcall mov lcall lcall mov lcall lcall mov P2, #0FFH ; move all ports HIGH P3, #0FFH P1, #0FFH P0, #0FFH sp, #65H ; init stack pointer TXC DLY1 dptr, #INITIALISE MESSAGE dptr, #COLLEGE MESSAGE DLY dptr, #NAME MESSAGE DLY dptr, #CLRSCR

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lcall MESSAGE mov dptr, #ENTER lcall MESSAGE mov ADC_VAL, #00H anl PCON, #7FH ; CLR SMOD BIT mov TMOD, #20H ; TIMER 1 IN MODE 2 mov TH1, #0E7H ; SET BAUD RATE AS 1200 mov SCON, #50H ; SERIAL MODE 1 AND RECEIVE ENABLE mov IE, #90H ; ENABLE SERIAL INTERRUPT setb TR1 ; RUN TIMER 1 setb SERL_INT ;> ; ;> MAIN: jnb SERL_INT, DONT_DISP_TMP clr SERL_INT lcall HTOD lcall DISP_TEMP DONT_DISP_TMP: mov A, P1 cjne A, #0FFH, NO_KEYPRESSED setb TXC lcall SERL_DLY1 mov SBUF, #055H CHAN9: jnb TI, CHAN9 clr TI lcall SERL_DLY1 mov SBUF, #055H CHAN13: jnb TI, CHAN13 clr TI lcall SERL_DLY1 mov SBUF, #055H CHAN11: jnb TI, CHAN11 clr TI lcall SERL_DLY1 clr TXC lcall SERL_DLY ljmp MAIN NO_KEYPRESSED: setb TXC lcall SERL_DLY1 ; 55 IS reset

; 55 IS reset

; 55 IS reset

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mov SBUF, #055H CHAN12: jnb TI, CHAN12 clr TI lcall SERL_DLY1 mov SBUF, #0AAH CHAN0: jnb TI, CHAN0 clr TI lcall SERL_DLY1 NO_KEYPRESSED1: jb KEY1, NOT_KEY1 mov dptr, #MOVE_FORD lcall MESSAGE mov A, #'1' mov SBUF, #'1' CHAN1: jnb TI, CHAN1 clr TI NOT_KEY1: jb KEY2, NOT_KEY2 mov dptr, #MOVE_REV lcall MESSAGE mov A, #'2' mov SBUF, #'2' CHAN2: jnb TI, CHAN2 clr TI NOT_KEY2: jb KEY3, NOT_KEY3 mov dptr, #MOVE_LEFT lcall MESSAGE mov A, #'3' mov SBUF, #'3' CHAN3: jnb TI, CHAN3 clr TI NOT_KEY3: jb KEY4, NOT_KEY4 mov dptr, #MOVE_RIGHT lcall MESSAGE mov A, #'4' mov SBUF, #'4' CHAN4: jnb TI, CHAN4 clr TI NOT_KEY4: jb KEY5, NOT_KEY5 mov dptr, #MOVE_CAMCC lcall MESSAGE ; AA IS HEADER

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mov A, #'5' mov SBUF, #'5' CHAN5: jnb TI, CHAN5 clr TI NOT_KEY5: jb KEY6, NOT_KEY6 mov dptr, #MOVE_CAMCCW lcall MESSAGE mov A, #'6' mov SBUF, #'6' CHAN6: jnb TI, CHAN6 clr TI NOT_KEY6: jb KEY7, NOT_KEY7 mov dptr, #ENTER lcall MESSAGE mov A, #'8' mov SBUF, #'8' CHAN7: jnb TI, CHAN7 clr TI NOT_KEY7: jb KEY8, NOT_KEY8 mov dptr, #ENTER lcall MESSAGE mov A, #'8' mov SBUF, #'8' CHAN8: jnb TI, CHAN8 clr TI NOT_KEY8: lcall SERL_DLY1 xrl A, #0AAH mov SBUF, A CHAN10: jnb TI, CHAN10 clr TI lcall SERL_DLY1 clr TXC lcall SERL_DLY ljmp MAIN ;> ; ;> DISP_LET: lcall READY ; Check weather display is ready

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setb setb mov clr nop setb clr ret ;> ; ;> DISP_COM: lcall READY clr DRS clr BUSY_CHEK mov P2, R7 clr DRW nop setb DEN clr DEN ret ;> ; ;> MESSAGE: ; sub for sending charactors to display push acc MESSAGE1: lcall READY ; Check weather display is ready clr a ; Clr accumulator movc a, @a+dptr ; Load accumulator with the contents of dptr inc dptr ; cjne a, #EOL, COMD ; If the data is not end of line goto comd pop acc ret ; if the data is end of line stop sending COMD: cjne clr clr sjmp DDATA: cjne a, #DAT, SENDIT comd setb DRS setb BUSY_CHEK sjmp MESSAGE1 SENDIT: ; set DRS to high ( DATA MODE ) ; goto message again ; ; a, #COM, DDATA ; if the data is not command goto data DRS ; COMMAND MODE BUSY_CHEK MESSAGE1 ; goto message again ; ; if the data is not data to be send goto ; Check weather display is ready ; place the data at port 1 ; send enable strobe ; return to message DRS BUSY_CHEK P2, R7 DRW DEN DEN

; place the data at port 1 ; send enable strobe

; return to message

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mov clr nop setb clr sjmp ;> ; ;> READY: ; sub to check display busy clr DEN ; disable display buffer mov p2, #0ffh ; set port1 in read mode clr DRS ; COMMAND MODE setb DRW ; READ MODE WAIT: ; clr DEN ; send enable strobe setb DEN ; jb p2.7, WAIT ; if display is not send ready signal be in loop clr DEN ; disable display buffer jnb BUSY_CHEK, NO_DRS_SET setb DRS NO_DRS_SET: ret ; return to message ;> ; ;> ; converting hex value into decimal HTOD: mov TMPR_VAL, #00H mov TMPR_VAH, #00H mov a, ADC_VAL cjne a, #00h, CHEKDA1 RET CHEKDA1: clr c mov R2, ADC_VAL mov a, #00h mov r1, #00h LOOP1: clr c inc a da a jnc CONT1 inc R1 CONT1: djnz R2, LOOP1 mov TMPR_VAL, a mov TMPR_VAH, r1 RET p2, a DRW DEN DEN MESSAGE1 ; place the data at port 1 ; set WRITE MODE ; send enable strobe ; ; goto message again

; END SUB

; END SUB

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;> ; ;> DISP_TEMP: mov R7, #0C0H lcall DISP_COM mov A, TMPR_VAH anl A, #0Fh add A, #30H mov R7, A lcall DISP_LET mov anl swap add mov lcall A, TMPR_VAL A, #0F0h A A, #30H R7, A DISP_LET

mov A, TMPR_VAL anl A, #0Fh add A, #30H mov R7, A lcall DISP_LET mov R7, #223D lcall DISP_LET mov R7, #'C' lcall DISP_LET mov R7, #' ' lcall DISP_LET RET ;> ; ;> DLY: mov r4, #1fh GONE: mov r5, #00h OUT: mov r6, #00h IN: djnz r6, IN djnz r5, OUT djnz r4, GONE ret DLY1: mov r4, #03h ; END SUB

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GONE1: mov r5, #10h OUT1: mov r6, #00h IN1: djnz r6, IN1 djnz r5, OUT1 djnz r4, GONE1 ret ;> ; ;> SERL_DLY: mov R6, #7FH SOUT: mov R7, #00H SIN: djnz R7, SIN djnz R6, SOUT RET ;> ; ;> SERL_DLY1: mov R6, #05H SOUT1: mov R7, #10H SIN1: djnz R7, SIN1 djnz R6, SOUT1 RET ;> ; ;> ;> ROM TABLE AREA ;> INITIALISE: db COM, 30h, 30h, 30h, 30h, 3ch, 06h, 0ch, 01h, EOL NAME: db COM, 80h, DAT, 'NAVIGATION ROBOT', COM, 0C0H, DAT,'WITH CAMERA F/B', EOL COLLEGE: db COM, 80h, DAT, 'SINDHURA COLLEGE', COM, 0C0H, DAT,'OF ENGG. @ TECH.', EOL ENTER: db COM, 80h, DAT, 'ENTER COMMAND...', EOL MOVE_FORD: db COM, 80h, DAT, 'MOVING FORWARD..', EOL MOVE_REV: db COM, 80h, DAT, 'MOVING REVERSE..', EOL MOVE_LEFT: db COM, 80h, DAT, 'MOVING LEFT... ', EOL MOVE_RIGHT: db COM, 80h, DAT, 'MOVING RIGHT... ', EOL MOVE_CAMCC: db COM, 80h, DAT, 'MOVING CAM CW.. ', EOL MOVE_CAMCCW:

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db COM, 80h, DAT, 'MOVING CAM CCW..', EOL CLRSCR: db COM, 01h, EOL ;> ; ;> END

Discussion of results Sl. No. 1 2 3 4 5 6 7 8 Input command Action observed key ‘↑’ or ‘1’ ‘↓’ or ‘2’ ‘→’ or ‘3’ ‘←’ or ‘4’ ‘L’ or ‘l’ ‘R’ or ‘r’ ‘U’ or ‘u’ ‘D’ or ‘d’ Vehicle moved in forward direction Vehicle moved in backward direction Vehicle turned towards right Vehicle turned towards left Camera moved left Camera moved right Stop
Table – Result table

CONCLUSIONS AND RECOMMENDATIONS
. In this project we just introduced wireless control for all operations to eliminate human interference in the vehicle. The operator can operate this from a distant place. The camera associated with the vehicle scans the location and the AM TX sends the

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scanned picture information which can be seen in TV set at the base station. Now the operator can see the location in the TV and accordingly commands are given. We used a light dependent resistor that measures the light intensity and if the intensity is low the lights automatically will be on. The communication link is two ways from MC to vehicle. Operator can know the temperature feed back of the location and also the vehicle movements. The power is provided from battery but there is no on-site recharging facility. With these features, we can operate this vehicle in invisible fields like mines, toxic areas and places where man cannot enter.

FUTURE SCOPE

The flexibility of the navigation system presented here means that a mobile robot can enter different environments, and the system automatically selects an appropriate set of sensors for each particular environment. It additionally means that the system can work without landmarks, but if they exist, they will be used to improve navigation accuracy.

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This kind of flexibility in the navigation system is of the utmost importance when in the near future increasingly mobile robots will move out from structured indoor environments into unknown outdoor environments.

BIBILOGRAPHY
1. 8051 programming and applications - by K.J.Ayala 2 Microprocessors and interfacing - by Douglas V.Hall 3. Mastering Serial Communications - Peter W. Gafton

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4. Linear Integrated Circuits - By: D. Roy Choudhury, 5. Op-Amps Hand Book - By: MALVIND 6. www.atmel.com 7. www.maxim.com 8. www.robotics.com 9. www.stepperworld.com

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