Design and Construction of a Microcontroller-based Mains Switch Control System
Chapter One
OBJECTIVES OF THE STUDY
This research aims to construct effective software and hardware for microcontroller-based main switch control systems. Specifically, the objectives are to produce a device that:
- Saves the time of going from one switch to another to prove the industrial equipment since the switches can be controlled remotely (computer system).
- Has a program control switch, which will help to reduce the use of manual switches, if not eliminate it
- To create a system that ensures the integrity of the complete microcontroller system during all forms of environmental stress (shock, transient noise)
- Removes friction with the use of the program control switch.
CHAPTER TWO
LITERATURE REVIEW
INTRODUUCTION
A control system is a device or set of devices used to manage, command, direct or regulate the behaviour of other devices or system. The term control system may be applied to the essentially manual controls that allow an operator to, for example close and open a hydraulic press, where the logic requires that it cannot be moved unless safety guards are in place.
There are two common classes of control systems with many variations and combinations: logic or sequential controls and feedback or linear controls. There is also fuzzy logic, which attempts to combine some of the design simplicity of logic (the study of the principles of valid inference and demonstration) with the utility of linear control. Some devices or systems are not controllable. An automatic sequential control may trigger a series of mechanical actuators (mechanical device form ring or controlling a mechanism or system) in the correct sequence to perform a task. In the case of linear feedback systems, a control loop, including sensors (a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument), control algorithms and actuators, is arranged in such a fashion as to try to regulate a variable at a reference value or set point. An example of this may be to increase the fuel supply to a furnace when a measured temperature drops. As Wikipedia cited, PID controllers (proportional- integral- derivative controller) is a generic control loop feedback mechanism widely used in industrial control system, attempts to correct the error between a measured process variable and a desired setpoint by calculating and then outputting a corrective action that can adjust the process accordingly to keep the error minimal. Open loop control systems do not directly make use of feedback, but run only in pre arranged ways. Pure logic control systems were historically implemented by electricians with network relays and designed with a notation called Ladder logic [3].
Today, most of such systems are constructed with programmable logic devices. ON – OFF control, for example a switch control is a simple negative- feedback, when light goes below a setpoint (SP), the light is switched OFF but when it goes above a setpoint, the light is switched ON, logic controllers may respond to switches, light sensor and pressure switches and cause the machinery to perform some operation. They are used to sequence mechanical operations in many applications. Some techniques are used in control system like the Derivative action which is a part concerned with the rate of change of the error with time. This action makes control system behave much more intelligently. The microcontroller- based switch control system uses specialized equipment to control the switching of electrical devices. Through the interface on the computer, one can switch on/off electrical appliances from remote places. Sayers et al. (1991) noted that technological advances in Digital Signal processor (DSPS), networking, microprocessors, and programmable logic devices (PLDS) have empowered designers with entirely new techniques and methodologies that were economically unthinkable two decades ago. These advances, along with increased performance demands, have fueled the push of digital technology deeper into the controlled devices. The justification often quoted for this push to digital control includes reproductively, increased stability, increased resolution and decreased infrastructure costs (networks replace control wiring) [4].
OVERVIEW OF LIGHTING CONTROLLER
A switch is a device that opens or closes a circuit. Switch is a device that causes the operation of a circuit between discrete specified levels. The technology of the automation evolves from a manually switching of devices “on” or “off”. This automation can be illustrated with a control system that uses a computer system to control the state (on/off) of appliances.
Advanced English Dictionary, defines control to mean the authority, or the power to influence or guide something. It can also be defined as the levers, switches and other instruments for operating a machine or other devices. Lighting Controller here can be defined as responsible for directing or controlling the light automatically whether remotely or locally in contrast with the manual control where people need to go to the located switch to turn on or off the light. This reflects the evolution from Energy Management Systems in which a central computer was used to control the lamps in a building. A lighting automation technology can enable the person by assisting in daily routines and enabling the individual to achieve tasks, they might not have previously been able to achieve. Tasks can range in levels of complexity from simple tasks such as turning on or off lights through to fully automating the majority of electrical systems within the building. Referring to Bill Gates (2000), We will be able to control our entertainment systems in simple but elegant ways, use any TV in the house to monitor inexpensive outdoor surveillance cameras and connect to the Internet from multiple locations [23]. Some of these tasks will not require a PC, but in the end it will make sense to have a computer to quietly orchestrate the operations of the systems in a house.
Most of the today’s lighting automation technologies requires computer to operate them. Even the stand alone designs need computer to be initialized. The existence of computer technology had driven the lighting automation technology into the right path. The capability of the lighting automation technology has transformed the environment to be an intelligent environment or smart environment (Heimer, 1995) [23].
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CHAPTER THREE
METHODOLOGY AND SYSTEM ANALYSIS
INTRODUCTION:
System Analysis means the procedural study of the operation of a system with an attempt to discover its problem areas i.e. to know why the system is not functioning properly and what can be done to restructure the system. This chapter is concerned with investigation and analysis of the existing system with a view to understanding how it works including the problems and limitations. The characteristic attributes of a problem situation where system analysis is required are complexity of the issue and uncertainty of the outcome of any course of action that might reasonably be taken. System analysis usually has some combination of the following: Identification and re- Identification of objectives, constrains, and alternative course of action; examination of the probable consequences of the alternative in terms of costs, benefits and risk; presentation of the results in a comparative framework so that the decision maker can make an informed choice from among the alternatives.
This chapter also deals with the methodology, considering the advantages of each and the justification of the need for the proposed system.
METHODOLOGY
Internationally Software Engineering has accepted standards for transforming ideas in software. They include:
- The structured system Analysis and Design methodology (SSADM)
- Prototyping
- Experts system methodology
- Usability engineering methodologies,
The methodology applied in the system is prototyping and is discussed below.
CHAPTER FOUR
SYSTEM DESIGN
INTRODUCTION:
In this chapter, the design of a switch control system is described for controlling appliances such as bulbs using a computer system through a serial port. The Graphical user interface (GUI) through which command is given to the switch controller circuit is achieved with visual basic. The system can control other appliances such as Television, Refrigerator, Ceiling fan etc. This design is a prototype of a switch control system which can be used in a large organization to control several electrical appliances connected to it. There is an interface provided by visual basic programming language, which contains “ON” buttons and “OFF” buttons through which control command is sent to electrical devices. Therefore when any command button is clicked to switch on or off, device signals go from the control module through the serial port, serial cable to the Max- 232 interface which amplifies the signals. The signal goes to the microcontroller and from the microcontroller the signal gets to the relay through the transistor down to the bulbs which are the receiving module. The design consists of two modules: the hardware and the software modules both working together to achieve the desired result. In the hardware module, the power source supplies current to all the hardware component of the control box. Max 232 acts as buffer that amplifies the signals coming from the computer. The 8051 microprocessor used is the controller that controls the relay and makes it function like a switch.
CHAPTER FIVE
SYSTEM IMPLEMENTATION AND TESTING
INTRODUCTION
The various units of the microcontroller- based mains switch control system (both the hardware and software subsystems) are implemented using different circuitry formulations that satisfy the aim of the design, and software coding using a specific software language that provide appropriate control as specified in the design
Concerning the implementation of this system the hardware part of the design; that is, the wired diagram of the system is shown. In chapter four the design of the system was shown to be consisting of three circuits, the power supply circuit, switching circuit and the data circuit. This chapter also states the system operation of the device. Brief attention was given to the issue of programming and the other constructions carried out during the design process. The chapter five of this work will deal with the implementation of the hardware and software designs, testing the system, and performance evaluation.
CHAPTER SIX
SUMMARY AND CONCLUSION
SUMMARY
In summary, the project work (A microcontroller-based mains switch control system) was introduced in chapter one giving us an insight that it was a microcontroller- based mains switch control system interfaced to a personal computer through which appliances could be switched ON or OFF without leaving one’s seat. In chapter two of the research work, various literatures on the topic under study were reviewed analyzing the invention, operations, function of microcontroller to control appliances. Chapter three provides an analysis of the existing system and proposed system as well as the methodology. Chapter four was based on the system design. Chapter five dealt with the system implementation and testing of the entire microcontroller- based mains switch control system. Finally this project is able to switch ON or OFF a device using computer system via serial port.
The system was designed in such a way that maintenance and repairs are easily done in case of any faults. Soldering techniques and practical electronic were carefully studied and the experience gained from it was instrumental to the success of this project
PROBLEMS ENCOUNTERED
Some problems were encountered in the cause of developing the prototype of this system. Most prominent is the issue of frequent power failure from the public power supply. This prolonged the wiring time. Secondly, the problem of some components initially tested okay not functioning on circuit board during testing.
CONTRIBUTION TO THE BODY OF KNOWLEDGE
The microcontroller based controlled system approach is an automated switching of appliances that leads to:
- Theeliminationof direct contact with switch by providing an interface on the computer screen through which the electrical devices will be
- The saving of the time it takes the operator going from one switch toanotheris a delight to the
- The ability to turn “ON” or “OFF” the selected electrical devicesanytime any day (e.g. in the hotel room, children’s room etc) is a plusto the
- Real-time
- System reliability in controlling power
- The elimination of user’s movement in switching ON or OFF the appliancesis an advantage to the physically
RECOMMENDATIONS
- Before going ahead to wire components on the circuit board ensurethat you test the hardware properly and simulate the design. This will enable you make all necessary adjustments to reduce mistakes and design
- For better implementation use the same family of chips if possible(i.e only TTL or only CMOS). This will ensure compatibility of
- Ensure to keep within specified values; because exceeding any ofthese values may cause a permanent damage to either the clips in particular or the entire system as a It is recommended that this work beused in industries such as hotels, schools to provide easy and safe use of the electrical The management of any organization using this work should employ a computer literate person to operate the system.
CONCLUSION
The result achieved in the design and construction of the microcontroller- based mains switch control system is actually a move away from manual mode of switching to that of automation. For the fact that the materials used are locally sourced make room for cost effectiveness of design and economic application viable.
The system was designed in such a way that maintenance and repairs are easily done in case of any faults.
REFERENCES
- IEEE Std 610.10-1994, IEEE Standard Glossary of Computer Hardware Terminology (Computer Hardware Dictionary)
- Osinuga and Oresotu (2001) Description of a Computer Port Interface (2001).
- Wikipedia the free encyclopedia (2008). History of Modern computing (http://www.wiki.com/histroy/mordencomputing).
- Sayers, A.P. Robson, A.E. Adams and G.E.Chester,(1991) Principles of Microprocessor, Hewlett-Packard Journal.
- Ismail, and V.M Rooney, (1987) Microprocessor Hardware and Software Concepts IT Press, Chicago.
- Takashi (1990) Observed the increase in processing capacity of evolving Microprocessors.
- Chris Kotoroski, (2008) A push –to – break breaks word toggle switch. [8]. Tendler,J.M. Dobson, S. Field, S. LE and Sinharoy, B. (2002) Power for system micro architecture, IBM Journal of Research and Development.
