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PC BASED MANUAL GUIDED VEHICLE USING RF WIRELESS TECHNOLOGY
The main aim of this project is to design a system that behaves like a robot and control it using RF technology. Robot is a system that contains sensors, control systems, manipulators, power supplies and software all working together to perform a task. Designing, building, programming and testing a robot is a combination of physics, mechanical engineering, electrical engineering, structural engineering, mathematics and computing.
This project describes a new economical solution of robot control systems. The presented robot control system can be used for different sophisticated robot applications. The control system consists of an RF transmitter and receiver, a microcontroller that collects data from the RF receiver and controls the robot.
The RF modules used here are STT-433 MHz Transmitter, STR-433 MHz Receiver, HT640 RF Encoder and HT648 RF Decoder. The controlling of the robot is done by providing the input from the PC at the transmitter. The microcontroller, at the transmitter side, accepts the input from the keyboard and passes this data to the RF transmitter.
At the receiving end, the RF receiver receives this data, gives it to RF decoder. This decoder converts the single bit data into 8-bit data and presents it to the microcontroller. Now, the controller read the data and performs the corresponding action according to the given input at the transmitter side i.e., to move the robot back, front, left or right.
SOFTWARE AND HARDWARE TOOLS:
Software Tools:
1. Keil compiler
2. Orcad.
3. Proload
Hardware Tools:
1. Microcontroller AT89S52.
2. RF transmitter and receiver modules.
3. RF encoder and decoder.
4. DC motors and L293D for Robot.
5. PC
6. MAX232
Block diagram
Transmitter section
Receiver section
INTRODUCTION TO EMBEDDED SYSTEMS
Introduction:
One of the more surprising developments of the last few decades has been the ascendance of the computers to a position of prevalence in human affairs. Today there are more computers in our homes and offices than there are people who live and work in them. Yet many of these computers are not recognized as such their users. In this chapter we’ll explain what embedded systems are and where they are found. We will also introduce the subject of embedded programming, explain why we have selected assembly programming as the languages for our project.
What is an 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. A good example is the microwave oven. Almost every household has one, and tens of millions of them are used everyday, but very few people realize that a processor and software are involved in the preparation of their lunch or dinner. This is indirect contract to the personal computer in the family room. It too is comprised of computer hardware and software and mechanical components. However, a personal computer is not designed to perform a specific function. Rather, it is able to do many different things.
Many people use the term general purpose computer to make this distinction clear. As shipped, a general – purpose computer is a blank slate: the manufacture does not know what the customer will do with it. One customer may use it for a network fileserver; another may use it exclusively for playing games and third may use it to write the great American novel. Frequently an embedded system. One embedded system controls the anti-lock brakes, another monitor and controls the vehicles emission and a third displays information on the dashboard.
If an embedded system is designed well, the existence of the processor and software could be completely unnoticed by a user of the device. Such is the case for a microwave oven, VCR or alarm clock. In some cases, it would even be possible to build an equivalent device that does not contain the processor and software. This could be done by replacing the combination with a custom integrated circuit that performs the same functions in hardware.
However, a lot of flexibility is lost when a design is hard coded in this way. It is much easier and cheaper to change a few lines of software than to redesign a piece of custom hardware.
History and Future:
Given the definition of embedded systems earlier in this chapter, the first such systems could not possibly have appeared before 1971. That was the year Intel introduced the world’s first microprocessor. This, chip the 4004 was designed for use in a line of business calculators produced by the Japanese company Busicom. In 1969, Busicom asked Intel to design a set of custom integrated circuits one for each of their new calculator’s models. The 4004 was Intel’s response.
Rather than design custom hardware for each calculator, Intel proposed a general purpose circuit that could be used throughout the entire line of calculators. This general purpose processor was designed to read and execute a set of instructions-software stored in an external memory chip. Intel’s idea was that the software would give each calculator its unique set of features.
Real- Time Systems:
One subclass of embedded systems is worthy of an introduced at this point. As commonly defined, a real-time system is a computer system that has timing constraints. In other words, a real-time system is partly specified in terms of its ability to make certain calculations or decisions in a timely manner. These important calculations are said to have deadlines for completion. And for all practical purposes, a missed deadline is just as bad as a wrong answer. The issue of what happens if a deadline is missed is a crucial one.
If instead the system is involved in satellite communication, the damage could be limited to a single corrupt data packet. The more severe the consequences, the more likely it will be said that the deadline is “hard” and thus the system a hard real-time system.
The Importance of Assembly Language in Embedded System:
Even those who absolutely hate assembly language will admit that if speed is your primary concern, assembly language is the way to go.
Speed: Assembly language programs are generally the fastest programs around.
Space: Assembly language programs are often the smallest.
Capability: You can do things in assembly language will help you write better programs, even when using HLLs.
Assembly language is the uncontested speed champion among programming languages. An expert assembly language programmer will almost always produce a faster program than an expert C programmer. While certain programs may not benefit much from implementation in assembly, you can speed up many programs by a factor of five or ten over their HLL counterparts by careful coding in assembly language: even greater improvement is possible if you’re not using an optimizing compiler.
Capability is another reason people resort to assembly language. HLLs are an abstraction of typical machine architecture. They are designed to be independent of the particular machine architecture. As a result, they rarely take into account any special features of the machine, features which are available to assembly language programmers. If you want to use such features, you will to use assembly language.
Introduction to Microcontroller:
Microcontroller is a true computer on a chip the design incorporates all of the features found in a Microprocessor CPU: ALU, stack pointer, program counter and registers. It has also had added additional features like RAM, ROM, serial I/O, counting and clock circuitry.
Like the Microprocessor, a microcontroller is a general purpose devices, but one that is meant to read data, perform limited calculations on that data and control the operation of a machine using a fixed program that is stored in ROM and that does not change over life time of the system.
The design approach of a microcontroller used a more limited set of single byte and double byte instruction that are used to move code and data from internal memory to ALU. Many instructions are coupled with pins on the IC package: the pins are capable of having several different pins depending on the wishes of the programmer