Design And Construction Of A Doorbell Cum Visitor Indicator
ABSTRACT
This doorbell cum visitor indicator circuit can also give identification of the visitor to your home in your absence. When you’re home, you can use it simply as a normal doorbell. The circuit comprises a monostable built around timer IC 555 (IC1), relay driver transistor BC548 (T1), inverter section built around IC 7404 (IC2), latching section built around IC 555 (IC3) and LED display driver transistor BC548 (T2).
TABLE OF CONTENTS
COVER PAGE
TITLE PAGE
APPROVAL PAGE
DEDICATION
ACKNOWELDGEMENT
ABSTRACT
CHAPTER ONE
1.0 INTRODUCTION
1.1 BACKGROUND OF THE PROJECT
- PURPOSE OF THE PROJECT
- AIM OF THE PROJECT
- OBJECTIVE OF THE PROJECT
- PURPOSE OF THE PROJECT
- LIMITATION OF THE PROJECT
- ADVANTAGES OF THE PROJECT
- PROBLEM OF THE PROJECT
- APPLICATION OF THE PROJECT
- RESEARCH QUESTION
- PROJECT ORGANISATION
CHAPTER TWO
LITERATURE REVIEW
- OVERVIEW OF THE STUDY
- REVIEW OF THE RELATED STUDY
CHAPTER THREE
3.0 CONSTRUCTION METHODOLOGY
3.1 BASIC OF THE SYSTEM
3.2 BLOCK DIAGRAM OF THE SYSTEM
3.3 SYSTEM OPERATION
3.4 CIRCUIT DIAGRAM
3.5 CIRCUIT DESCRIPTION
3.6 DESCRIPTION OF COMPONENTS USED
3.7 POWER SUPPLY UNIT
CHAPTER FOUR
4.0 TESTING AND RESULTS
- CONSTRUCTION PROCEDURE AND TESTING
- INSTALLATION OF THE COMPLET DESIGN
- ASSEMBLING OF SECTIONS
- TESTING OF SYSTEM OPERATION
- COST ANALYSIS
CHAPTER FIVE
- CONCLUSION
- RECOMMENDATION
- REFERENCES
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Visitor indicator circuit
The circuit (see Fig. 1) comprises a monostable built around timer IC 555 (IC1), relay driver transistor BC548 (T1), inverter section built around IC 7404 (IC2), latching section built around IC 555 (IC3) and LED display driver transistor BC548 (T2).
Fig. 1: Circuit diagram of doorbell cum visitor indicator
The monostable output drives the relay through transistor amplifier T1. The normally-opened (N/O) contact of the relay connects an electric bell with mains supply as shown in Fig. 1. The output of the monostable also goes to inverter N1, which, in turn, enables the latching circuit built around IC3 in conjunction with DPDT slide switch S2. The output of IC3 at its pin 3 is fed to LED1 (visitor-out indicator) and LED2 through LED16 via LED driver transistor T2.
The switch panel shown in Fig. 2 is to be mounted on the entry gate or door, while the LED display panel shown in Fig. 3 is to be kept inside the house near the owner’s desk.
Fig. 2: Switch panel to be mounted on the gate Fig. 3: Suggested LED display to be kept nearthe owner’s desk
Circuit operation
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Before you leave your house, slide switch S2 (Out) to ‘on’ position and press reset switch S3 once. When somebody visits your home and presses doorbell switch S1, it will trigger the monostable (IC1) and also energise the relay to ring the bell. The monostable output through inverter N1 will enable the latching circuit and LED1 will glow continuously to indicate that you’re out of the house.
The message “Please indicate the first letter of your name (single alphabet in English only) by flipping switches S4 through S18 to ‘on’ position,” as required, is written just below LED1 indicator as shown in Fig. 2.
Suppose the visitor’s name is Tina Chopra. As the initial alphabet of her first name is ‘T,’ she has to flip the topmost-row and middle-column switches towards ‘on’ position. The position of the switches for this example is shown in Fig. 2.
When you return home, just flip switch S19 to ‘on’ position to check the visitor’s initial. The topmost-row and middle-column LEDs will glow to indicate the alphabet ‘T,’ so you know that one of your friends having name starting with ‘T’ had visited your place in your absence. The status of the LEDs for this example is shown in Fig. 3 by the red LEDs.
Now you can slide switch S2 to ‘off’ position or press reset button S3 once. When the indicator is not in use, slide DPDT switch S2 to ‘off’ position to bypass the latching and LED display sections by cutting off the power supply and thus prevent unnecessary continuous drain of power. Now the rest of the circuit will work as a doorbell only.
The rows and columns may be increased to accommodate a 5×7 display matrix. The circuit can be used for a single visitor only.
The Title Page should be the first section of your project “Design And Construction Of A Doorbell Cum Visitor Indicator”, 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 A Doorbell Cum Visitor Indicator 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 A Doorbell Cum Visitor Indicator 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 A Doorbell Cum Visitor Indicator 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 A Doorbell Cum Visitor Indicator 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