Design And Construction Of Temperature Sensing Alarm

ABSTRACT

This project is titled design and construction of a temperature sensing alarm system. This circuit is a temperature sensing as well as alarm circuit. The circuit raises an alarm whenever the temperature crosses a certain limit. Temperature monitoring is a very important and frequently used application in industries and in many other places where the temperature should be kept below a maximum allowable level. This circuit comes to our rescue when a situation of that sort arises. And this can be achieved by the use of temperature sensor known as THERMISTOR. This thermistor is a temperature control device with a high or low resistance value which can go high or low when the temperature is increased or reduced depending on the type.

TABLE OF CONTENT

Title Page

Approval Page

Dedication

Acknowledgement

Abstract

Table of Content

CHAPTER ONE

1.0 Introduction

1.1 objective of the project

1.2 significance of the project

1.3 application of the project

1.4 scope of the project

1.5 limitation of the project

1.6 project organisation

CHAPTER TWO

2.0 Major Component’s Description

2.1 Resistors

2.2 Diodes

2.3 Capacitors

2.4 Transformers

2.5 Transistor

2.6 Integrated Circuit

2.7 Thermistor

2.8 buzzer

CHAPTER THREE

3.0 methodology

3.1 system block diagram

3.2 system circuit diagram

3.3 system description and operation

CHAPTER FOUR

4.0 Construction Procedure and Testing

4.1 Casing and Packaging

4.2 Assembling of Sections

4.3 Testing of System Operation

4.4 Installation of the Completed System

4.5 Problem Encountered

4.6 Cost Analysis

CHAPTER FIVE

5.1 Conclusion

5.2 Recommendation

5.3 Bibliography

CHAPTER ONE

1.0 INTRODUCTION

1.1 BACKGROUND OF THE PROJECT

Nowadays, rate of fire accident cause by heating appliances in this country is high. So there is every need that other means of safety should be made available for constant running of our electric equipments and gadgets and also to provide comfort to man. Hence, with the help of a Thermistor, which has come to solve the problem of fire accident and inaccuracy found in temperature measurement in Nigeria, a steady running and operation of our electric equipments and gadgets is guaranteed.

Temperature controlled circuits typically uses a temperature sensor (also known as a thermistor) to sense the water temperature and the steam when the water is boiled, and then cut off the electric power if the water temperature reaches the action temperature point or if sufficient amount of steam is detected.The temperature sensors, NTC (Negative Temperature Coefficient) resistors (thermistor), which is capable of sensing the water temperature through a very wide range of points.

A temperature sensing alarm system has a sensor which is mounted at the system to the measure when the temperature of a certain object exceed the required limit. A conventional temperature control system typically uses a bi-metal temperature sensor (also known as a thermostat) to sense the water temperature and the steam when the water is boiled, and then cut off the electric power if the water temperature reaches the bi-metal action temperature point or if sufficient amount of steam is detected. Some modern electric kettles use more precise electronic temperature sensors such as the NTC (Negative Temperature Coefficient) resistors (thermistors), which are capable of sensing the water temperature through a very wide range of points instead of just one point. In some cases, the control systems of the electric kettles are configured to take into account the temperature rising rate in addition to the water’s absolute temperature value so that the control precision is greatly improved. However, the heating system of an electric kettle is a very complicated energy balancing system. This device can be used in measuring or monitor the temperature of water in a kettle. The heat generated by the heating element may be decomposed into the following main components:

1. a) Energy for heating up the water in the water tank;
2. b) Energy stored in the heat conducting base;
3. c) Energy dissipated through the outer case of the water tank and related to the case material and the case mass; and
4. d) Energy dissipated by emission through the surface the outer case and related to the surface area and the color of the water tank’s body.

All of the above factors will affect the water temperature during the heating up and warmth keeping cycle, which may increase the difficulty of precisely controlling the water temperature. For example, the energy stored in the heat conducting base may increase the water temperature by a certain amount after the power supply is cut off, which causes the water temperature to overshoot. The choice of the material of the outer case may affect the water temperature significantly because energy loss is very serious when the water temperature is high. All these factors and effects should be taken into consideration in the design of electric kettles.

1.2 OBJECTIVE OF THE PROJECT

The objective of this work is to design a temperature monitoring device which can monitor a temperature range of 0°C -100°C automatically – without the help of the user. This device blows an alarm whenever the temperature gets to the set value.

1.3 SIGNIFICANCE OF THE PROJECT

The idea behind the design and construction of this system is to make available or alternative means providing safety and accuracy demand for electric appliances using for household or industrial purpose. This goes a long way in helping to curb the problem frequently encountered as a result of fire outbreak, burning of food, and inaccuracy found in measuring and maintaining temperature. That notwithstanding it makes it possible to have other means of heating food without constant temperature monitoring until when the required temperature will be achieved thereby creating time for the operator to be engaged on other works while the system is in operation.

1.4 APPLICATION OF THE PROJECT

Outside the culinary world, temperature sensing alarms are used for a number of purposes.

A furnace can be used either to provide heat to a building or used to melt substances such as glass or metal for further processing. A blast furnace is a particular type of furnace generally associated with metal smelting (particularly steel manufacture) using refined coke or similar hot-burning substance as a fuel, with air pumped in under pressure to increase the temperature of the fire.

A kiln is a high-temperature temperature control electric kettles used in manufacturing to convert mineral feedstock (in the form of clay or calcium or aluminum rocks) into a glassier, more solid form. In the case of ceramic kilns, a shaped clay object is the final result, while cement kilns produce a substance called clinker that is crushed to make the final cement product.

An autoclave is an kettle-like device with features similar to a pressure cooker that allows the heating of aqueous solutions to higher temperatures than water’s boiling point in order to sterilize the contents of the autoclave.

Industrial temperature control electric kettles are similar to their culinary equivalents and are used for a number of different applications that do not require the high temperatures of a kiln or furnace.

1.5 SCOPE OF THE PROJECT

Temperature controlled circuits include an alarm for producing sound, a sensor for sensing the temperature of the water, and a control unit being configured to collect data during the operation of the circuits. The control unit is also configured to execute a predetermined program and calculate a cut-off temperature based on the data and a predetermined target temperature. The control unit is further configured to turn ON the alarm the monitoring objects exceed the required limit.

1.6 LIMITATION OF THE PROJECT

Though temperature sensing alarm circuits is can be used to monitor liquid, but when the sensor is directly exposed to liquid (water) can damaged the sensor thereby causing the sensor or the whole system to malfunctioning.

1.7 PROJECT WORK ORGANISATION

The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:

Chapter one of this work is on the introduction to the study. In this chapter, the background, significance, objective limitation and problem of the study were discussed.

Chapter two is on literature review of this study. In this chapter, all the literature pertaining to this work was reviewed.

Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.

Chapter four is on testing analysis. All testing that result accurate functionality was analyzed.

Chapter five is on conclusion, recommendation and references.