Design And Construction Of An Accurate Foot-Switch
Certain industrial controls require accurate switching operations. For example, in case of a foot-switch for precise drilling work, even a small error in switching may cause considerable loss. This low-cost but accurate foot-operated switch can prevent that.
The heart of the circuit is IC NE555 timer which is wired in one-shot mode. Its output pin 3 goes high only when both switches S1 and S2 are pressed simultaneously. You can release any one of the switches without changing the output state. When you release both the switches, the output goes low. The switches are placed under a foot paddle. LED1 is used as a warning indicator. If either S1 or S2 gets pressed erroneously, LED1 blinks to warn the operator. The operator can then withdraw his foot in case of a mistake or depress the other switch also to trigger the circuit. LED1 is to be mounted on the operator’s desk.
TABLE OF CONTENTS
TITLE PAGE
APPROVAL PAGE
DEDICATION
ACKNOWLEDGEMENT
ABSTRACT
TABLE OF CONTENT
CHAPTER ONE
1.0 INTRODUCTION
1.1 BACKGROUND OF THE PROJECT
1.2 AIM OF THE PROJECT
1.3 OBJECTIVE OF THE PROJECT
1.4 SIGNIFICANCE OF THE PROJECT
1.5 PURPOSE OF THE PROJECT
1.6 APPLICATION OF THE PROJECT
1.7 ADVANTAGES OF THE PROJECT
1.8 PROBLEM/LIMITATION OF THE PROJECT
1.9 PROJECT ORGANISATION
CHAPTER TWO
2.0 LITERATURE REVIEW
2.1 REVIEW OF RELATED STUDIES
2.2 REVIEW OF RELATED TERMS
2.3 REVIEW OF 555 TIMER IC
CHAPTER THREE
3.0 CONSTRUCTION METHODOLOGY
3.1 SYSTEM CIRCUIT DIAGRAM
3.2 SYSTEM OPERATION
3.3 CIRCUIT DESCRIPTION
3.4 SYSTEM CIRCUIT DIAGRAM
3.5 CIRCUIT OPERATION
3.6 IMPORTANCE AND FUNCTION OF THE MAJOR COMPONENTS USED IN THIS CIRCUIT
3.7 POWER SUPPLY UNIT
CHAPTER FOUR
RESULT ANALYSIS
4.0 CONSTRUCTION PROCEDURE AND TESTING
4.1 CASING AND PACKAGING
4.2 ASSEMBLING OF SECTIONS
4.3 TESTING
4.4.1 PRE-IMPLEMENTATION TESTING
4.4.2 POST-IMPLEMENTATION TESTING
4.5 RESULT
4.6 COST ANALYSIS
4.7 PROBLEM ENCOUNTERED
CHAPTER FIVE
5.1 CONCLUSION
5.2 RECOMMENDATION
5.3 REFERENCES
3.1 BLOCK DIAGRAM
Before carrying out any project, the block diagram must be drawn and fully understood. Block diagram gives a pictorial understanding of any work. The block diagram of the system is as below:
Fig. 1: Circuit of the foot-switch
The switches are placed under a foot paddle as shown in Fig. 2. LED1 is used as a warning indicator. If either S1 or S2 gets pressed erroneously, LED1 blinks to warn the operator. The operator can then withdraw his foot in case of a mistake or depress the other switch also to trigger the circuit. LED1 is to be mounted on the operator’s desk.
The circuit operation is simple. Resistors R2, R3 and R4 form a voltage divider. IC NE555 has two comparators, a flip-flop and power output section built into it. Pressing either S1 or S2 puts the input voltage between the upper comparator (2/3Vcc) and the lower comparator (1/3Vcc). Thus, it has no effect on the state of the internal flip-flop of IC NE555. Pressing the two switches simultaneously sets the flip-flop and the output of NE555 goes high. Transistor T2 energises relay RL1 for driving the load.
Fig. 2: Foot paddle switch
Releasing any of the switches brings the comparator voltage back to the initial level inside NE555 and it has no effect on the state of the flip-flop. Releasing both the switches brings the input level with respect to ground below the low trigger level, and thus it resets the output.
Use of the voltage divider results in stable operation over the entire permissible supply voltage range. The RC circuit at pin 4 provides power-on reset.
When only S1 is pressed, R3 (1 kilo-ohm) is less than R5 (1.5 kilo-ohms) and IC1 is not triggered. However, transistor T1 (BC548) gets forward biased and LED1 glows. When both S1 and S2 are pressed, the effective resistance between +Vcc and pin 2 of IC1 is about 500 ohms, which is less than R5 (1.5 kilo-ohms), and IC NE555 gets triggered.
The Title Page should be the first section of your project “Design And Construction Of An Accurate Foot-Switch”, providing essential details like the project title, your name, your supervisor’s name, the institution, and the submission date. After that, the Abstract offers a brief summary of your project, touching on its purpose, methods, results, and conclusions in 150-300 words. The Acknowledgments section is where you can thank those who supported your research, such as your supervisor, peers, or organizations that provided resources.
Next, the Table of Contents organizes the Design And Construction Of An Accurate Foot-Switch by listing its chapters and sections, along with page numbers for easy reference. The List of Figures and List of Tables help guide readers to specific visual elements like graphs, charts, or tables included in the document. There should also be an Abbreviations and Glossary section to explain any specialized terms or acronyms, making the content clearer to readers unfamiliar with the technical language.
The main body of the Design And Construction Of An Accurate Foot-Switch should start with the Introduction, which provides background information, outlines the research problem, states your objectives, and gives a brief overview of your research methods. Following that, the Literature Review offers an in-depth look at previous research relevant to your project, identifying gaps your study aims to address. The Methodology section then explains the research design, tools, and data collection methods you used to conduct the project and analyze the data.
In the Results and Discussion section, you present your findings and discuss them in relation to the Design And Construction Of An Accurate Foot-Switch research questions or objectives, often using tables or charts to help explain the data. The Conclusion summarizes the key results, discusses their implications, and suggests possible directions for future research. You may also include recommendations based on your findings, offering practical advice for improvements or applications. Finally, the Design And Construction Of An Accurate Foot-Switch project should include a References or Bibliography section to list all the sources you cited, as well as Appendices for any additional material. A Statement of Originality is often included to confirm the authenticity of your work