DESIGN AND CONSTRUCTION OF HEAT DETECTOR

Abstract

This project work focuses on the design and construction of heat detector for use in homes, industries, offices etc. It uses thermistor as the heat sensitive element; which is a type of resistor whose resistance changes significantly according to temperature change. The thermistor was connected as a voltage divider to one input therminal of the comparator (Pin 2) of the 555 timer IC as the resistance of the thermistor increases, the voltage at pin 2 decreases. Thus pin 1 becomes high and biases the N.P.N transistor moleing it to drive the 9V input load which activities the alarm circuit with the design of rate-of-heat detector a temperature increase of the sensor, to output is at 75oC or more per minutes; that is to trigger alarm. The heat sensor can be said to be ideal for environments with high dust or rapaid fire development.

Table of Content
Title Page: =================================    i
Certification: ==============================    ii
Table of Content: ===========================    iii

Chapter One
1.0    Introduction: =========================        1
1.1    Background of the Study: ================         1
1.2    Statement of the Problem: ================         4
1.3    Objective of the Study: ================            4
1.4    Significance of the Study: =================     5    
1.5    Scope of the Study: ======================     6
1.6    Research Question: ======================     6

Chapter Two
Literature Review: ===========================     8
2.1    Heat (Heat Transfer): =====================        8
2.2    Sensor: ===============================        11
2.2.1    Heat Sensor: ===========================       15
2.2.2    Electromechanical: ======================       17
2.2.3    Optomechanical: ========================       20
2.2.4     Electropneumatic: ======================       21
2.3    Application of Heat Sensor: ===========           22
2.4    Forms of Heat Sensor: ===============           24
2.4.1    Thermo couples: ====================           25
2.4.2     Resistant Temperature Devices (RTD): ======        26
2.4.3     Infrared Sensors: ======================        27
2.4.4 Bimetallic Devices: ================= ====        27
2.4.5     Thermometers: ========================       28
2.4.6 Silicon Diode: ======================               29
2.4.7 Thermostat: ==========================        29
2.5    Description of Component: ===============       30
2.5.1     Thermistor: ==========================      31
2.5.2 Transistor: ===========================      32
2.5.3 Resistor =============================      33
2.5.4 Capacitor: ===========================      35
2.5.5 Buzzer: =============================     36
2.5.6 Veroboard: ===========================     37
2.5.7   Light Emitting Diode: =================     37

Chapter Three
Materials and Method: =======================    39
References: ================================    48