Design And Construction Of A Digital Frequency, Temperature And Voltage Meter

ABSTRACT

This work is building a frequency, temperature and voltage meter. Digital frequency meter measures power supply frequency in the range 48 – 52 Hz to an accuracy of three decimal places has been designed and constructed using an 8-bit micro-controller. Digital voltmeters can measure a range of alternating current (AC) voltages, direct current (DC) voltages, or both AC and DC voltages. Devices typically display between three and seven digits. Whilst the temperature measuring device displays temperature information numerically.

The whole system incorporates a microcontroller which is interfaced to other components. These components include temperature sensor, frequency sensor, temperature sensor, arduino microcontroller and a 16×2 LCD display unit. At the end of this work a multipurpose meter was built which measures the three mentioned physical qualities which is the aim of this study.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

CHAPTER ONE

INTRODUCTION

1.1      BACKGROUND OF THE PROJECT

• PROBLEM STATEMENT
• AIM AND OBJECTIVE OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• SCOPE OF THE PROJECT

CHAPTER TWO

LITERATURE REVIEW

• OVERVIEW OF A VOLTMETER
• TYPES OF VOLTMETER
• HISTORICAL BACKGROUND OF DIGITAL VOLTMETER
• BASICS OF DIGITAL FREQUENCY METETR
• DESCRIPTION OF HERTZ
• HERTZ REVIEW
• REVIEW OF DIFFERENT TEMPERATURE SENSORS

CHAPTER THREE

METHODOLOGY

• BLOCK DIAGRAM
• SYSTEM CIRCUIT DIAGRAM
• SYSTEM OPERATION
• CIRCUIT DESCRIPTION
• PROGRAM CODE
• POWER SUPPLY UNIT
• ATMEGA88 UNIT
• LCD DISPLAY

CHAPTER FOUR

TESTING AND RESULTS

• CONSTRUCTION PROCEDURE AND TESTING
• INSTALLATION OF THE COMPLET DESIGN
• ASSEMBLING OF SECTIONS
• TESTING OF SYSTEM OPERATION

CHAPTER FIVE

• CONCLUSION
• RECOMMENDATION

REFERENCES

CHAPTER ONE

1.0                                                        INTRODUCTOIN

1.1                                           BACKGROUND OF THE STUDY

A measuring instrument is a device to measure a physical quantity. In the physical sciences, quality assurance, and engineering, measurement is the activity of obtaining and comparing physical quantities of real-world objects and events (Jones, 2012). Established standard objects and events are used as units, and the process of measurement gives a number relating the item under study and the referenced unit of measurement. Measuring instruments, and formal test methods which define the instrument’s use, are the means by which these relations of numbers are obtained. All measuring instruments are subject to varying degrees of instrument error and measurement uncertainty (Jones, 2012).

This study covers building a digital device that measures three physical quantities – frequency, temperature and voltage.

Digital frequency meter is a general purpose instrument that displays the frequency of a periodic electrical signal to an accuracy of three decimal places. It counts the number events occurring within the oscillations during a given interval of time (Jones, 2012). As the preset period gets completed, the value in the counter display on the screen and the counter reset to zero. Various types of instruments are available which operates at a fixed or variable frequency. But if any frequency meter operates at a different frequency than specified range, it could carry out abnormally. For measuring low frequencies, the deflection type meters are widely used. The deflection of the pointer on the scale shows the change in frequency. The deflection type instruments are of two types: one is electrically resonant circuits and other is ratio meter (Mullin, 2015).

Digital voltmeter is an instrument that measure voltage or voltage drop in a circuit. Digital voltmeter uses solid-state components and display values digitally. Typically, Digital voltmeters (digital volt meters) can be used to locate excessive resistance that may indicate an open circuit or ground. They are also used to identify low voltage or voltage drops that may indicate a poor connection. The positive lead is connected to the circuits positive side and the negative lead is connected to the circuits ground. The digital voltmeters internal resistance is the impedance, which is usually expressed in ohms per volt. This amount is relatively high in order to prevent the device from drawing significant current and disturbing the operation of the circuit being tested. The sensitivity of the Volt meter determines the range of voltages that digital voltmeters can measure (Mullin, 2015).

Digital voltmeters can measure a range of alternating current (AC) voltages, direct current (DC) voltages, or both AC and DC voltages. Some digital voltmeters can capture minimum and maximum voltages called spike readings. Others measure the root mean square (RMS), a range of frequencies, or the signal power in decibels.

A temperature meter measures the temperature of beings or things. The most widely recognized temperature meter is a mercury thermometer used to measure the temperature of people. These thermometers consist of a graduated glass capillary with a pool of mercury in one end. However, there are many different types of temperature meters, such as digital thermometers that take temperature measurements on contact with an object or infrared temperature meters that take measurements at distance, without contact (Mullin, 2015).

This temperature meter devices can indicate temperature in °C (Celsius), °K (Kelvin) and °F (Fahrenheit). This study is aimed building a battery power multiple digital meter that measures frequency, temperature and voltmeter (Mullin, 2015).

The work is organized as follows: chapter one discuses the introductory part of the work,   chapter two presents the literature review of the study,  chapter three describes the methods applied, chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.

1.2                                                  PROBLEM STATEMENT

Measurement of physical quantities such as frequency, temperature and voltage is very important in electrical and electronics field. Purchasing or building separate devices for measurement of these physical quantities can be difficult, time consuming and costlier. In other to overcome these challenges, a three-multi option digital meter was built. The digital display systems of this meter also overcome challenges seen in analogue frequency, temperature and volt meter such as having pointer across a scale in proportion to the voltage of the circuit and also have interpolation errors and moving parts (Mullin, 2015). Whilst this digital meter is more accurate than analog type. They reduce reading and interpolation errors. In digital meters, parallax errors are eliminated.

1.3                                    AIM AND OBJECTIVES OF THE STUDY

The main aim of this work is to build a digital meter which has multi option of measuring frequency, temperature and voltage. The objectives of this study are:

1. To digitally determine the value frequency, temperature and voltage
2. To increase accuracy

• To improve the overall performance of frequency, temperature and voltage meter.

1.4                                           SIGNIFICANCE OF THE STUDY

Carrying out this work is a way of making student becoming conversant with microcontroller controller.

This study will help readers of the work to understand the advantages of digital voltmeter over analogue. This implementation is work will help the student to know how to build a rugged and very much reliable digital meter.

Working on this study shall serve as a means of providing a handy and less exorbitant measuring instrument for the school engineering laboratory.

1.5                                                   SCOPE OF THE STUDY

The scope of this work covers building a multiple digital meters that measures frequency, temperature and voltmeter. Microcontroller is the hearts of the circuits which accepts and display the measured quantities via LCD. LCD (Liquid Crystal Display) screen is an electronic display module and find a wide range of applications. A 4×20 LCD display is very basic module and is very commonly used in various devices and circuits. These modules are preferred over seven segments and other multi segment LEDs. The reasons being: LCDs are economical; easily programmable; have no limitation of displaying special and even custom characters (unlike in seven segments), animations and so on.