Description
This alarm plays your prerecorded voice message. It is built around the readily available quartz clock. Take the buzzer out of the quartz clock and connect its positive terminal to pin 1 and negative terminal to pin 2 of optocoupler IC MCT2E (IC2). Pin 4 of IC2 is grounded and pin 5 is connected to trigger pin 2 of monostable multivibrator.
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
KEYWORD: alarm using your own voice, sound activated alarm, sound activated switch, diy sound activated switch, noise sensor alarm, history of sound activated switch, sound activation, sound operated circuit, sound trigger circuit
IC 555 (IC3) as shown in Fig. 2.
Fig. 1: Voice recording circuit
Fig. 1 shows the circuit for recording your voice message. When you press switch S2, it plays the meassage. The control circuit shown in Fig. 2 avoids the need for pressing switch S2 and thereby sounding the voice alarm automatically at the preset time.
Connect points A and B of the recording circuit to the corresponding points A and B of the control circuit. After making the connections, press record switch S1 to record your 6-second voice message through condenser microphone. Set the desired alarm time in quartz clock. At the time of alarm, buzzer terminals provide voltage to the internal LED of optocoupler IC2. This results in conduction of internal transistor of IC2, and its collector voltage at pin 5 drops to trigger IC3. The output of IC3 goes high for approximately 6 seconds. During this period, the prerecorded message is heard continuously. The message repeats every 6 seconds. The sound is loud enough in a room.
Fig. 2: Voice control circuit
The circuit operates off 3 volts and it can be easily fitted in a small box and fixed on the back side of the alarm quartz clock.
The voice control circuit is generally made up of 555 Timer IC. The circuit is shown above which generally includes MCT2E IC, 555 IC, two 2k resistors, 2.2k resistor, 56k resistor, 2 capacitors and one BC547 transistor.
This circuit is very useful for home and office use, if you want to give any message to your guests or clients when it is locked.
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