Design And Construction Of A Luxmeter Using A Light Dependent Resistor

A luxmeter is a device that measures illuminance and luminous emittance using the SI unit of lux.  It effectively measures the amount of power from the light falling on a given unit of area, except that the power measurement is weighted to reflect the sensitivity of the human eye to varying wavelengths of light.  A lux meter measures how bright the light falling on the sensor is. The aim of this work is to build a luxmeter using Arduino, an LCD shield, the LDR, and a 5 kohm resistor.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

CHAPTER ONE

1.0      INTRODUCTION

1.1      BACKGROUND OF THE PROJECT

• PROBLEM STATEMENT
• AIM AND OBJECTIVE OF THE PROJECT
• PURPOSE OF THE PROJECT
• SCOPE OF THE PROJECT
• LIMITATION OF THE PROJECT
• APPLICATION OF THE PROJECT
• RESEARCH QUESTION
• METHODOLOGY
• PROJECT ORGANISATION

CHAPTER TWO

LITERATURE REVIEW

• REVIEW OF MEASURING LIGHT INTENSITY USING A LUX METER
• REVIEW OF THE RELATED STUDY
• OVERVIEW OF LUX

CHAPTER THREE

3.0     METHODOLOGY

3.1     BLOCK DIAGRAM OF THE SYSTEM

3.2      SYSTEM WORKING PRINCIPLE

3.3      HARDWARE REQUIRED

3.4      LUX METER BUILDING

3.6     SYSTEM CODE

3.7      IMPLEMENTATION

CHAPTER FOUR

4.0      TESTING AND RESULTS

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

CHAPTER FIVE

• CONCLUSION
• RECOMMENDATION
• REFERENCES

CHAPTER ONE

1.0                                                        INTRODUCTION

1.1                                           BACKGROUND OF THE STUDY

Accurate and quantifiable measurement of light is essential in creating desired outcomes in practical day to day applications as well as unique applications. From measuring the amount of light in a work space surface, to ensuring emergency exits have proper illumination, light measurement and analysis is an important step in ensuring efficiency and safety. To perform these measurements, technicians often make use of lux meters which are specialized devices that measure the intensity of light falling on a surface, or “lux.”[1] [8]

Luminous intensity is a measure of the wavelength-weighted power emitted by a light source in a particular direction per unit solid angle, based on the luminosity function, a standardized model of the sensitivity of the human eye. The SI unit of luminous intensity is the candela (cd), an SI base unit. The lux (symbol: lx) is the SI unit of illuminance and luminous emittance, measuring luminous flux per unit area. It is equal to one lumen per square meter. In photometry, this is used as a measure of the intensity, as perceived by the human eye, of light that hits or passes through a surface. It is analogous to the radiometric unit, watts per square meter, but with the power at each wavelength weighted according to the luminosity function, a standardized model of human visual brightness perception. In English, “lux” is used in both singular and plural.

The light sensor for a lux meter can be one of several different types of sensors, including photodiodes and phototransistors, but the easiest to use and often the most readily available type of sensor is a photoresistor or light dependent resistor (LDR).  As you would expect, the resistance of an LDR changes as the amount of light falling on it changes.  If you can measure the resistance of the LDR and you know the characteristics of your particular LDR, you can quantify the amount of lux falling on the LDR.  In general, the brighter the light, the lower the resistance, but unfortunately, the relationship between resistance and lux for an LDR is not a nice linear relationship.  It is instead an exponential relationship which is a little trickier to deal with.  With a little bit of time though, you can take a few measurements to determine the mathematical relationship between resistance and lux and program the relationship into a microcontroller to create a simple and reasonably effective lux meter.

1.2                                                  PROBLEM STATEMENT

It is very difficult to determine the amount of light in a particular environment with our physical eyes, in order to solve this problem a lux meter was build. A luxmeter is a device measures illuminance and luminous emittance using the SI unit of lux.  It effectively measures the amount of power from the light falling on a given unit of area, except that the power measurement is weighted to reflect the sensitivity of the human eye to varying wavelengths of light.  A simpler way to describe a lux meter is to say that it measures how bright the light falling on the sensor is.

1.3                                   AIM AND OBJECTIVE OF THE PROJECT

The main aim of this work is to build a device that measures illuminance and luminous emittance using the SI unit of lux. At the end of this work, student involved shall be able to achieve the following:

1. process of characterizing an LDR,
2. writing software that can calculate illuminance and

• then building an LDR and Arduino based luxmeter.

1.4                                              PURPOSE OF THE PROJECT

The purpose of this work is to effectively measures the amount of power from the light falling on a given unit of area

1.5                                          APPLICATION OF THE PROJECT

Lux meter is used to measure the intensity of light. These precise measuring tools have been carefully engineered using state of the art technology and find usage in multiple applications, such as in Photographic Mesurements : It also measures the photography subject’s illuminance. Also In photometry, this is used as a measure of the intensity, as perceived by the human eye. We use it in our labs to measure visibility and maintains it by providing extra bulbs/tubes, so that we can provide good visibility to complete day to day tasks with comfort.

Lux meter also used to measure levels of light in schools, hospitals, production areas, laboratories

1.6                                                 SCOPE OF THE PROJECT

The amount of light is an important issue in several scenarios ranging from scenic design, light pollution study, robots navigation, occupational health and safety, illumination engineering, agriculture, medical appliances and many more. It is typically determined by using an illumination meter. The meter, also known as lux meter is used to measure the density of light in an area which measured in lx unit. It is used in photometry as a measure of the intensity, as perceived by the human eye of light that hits or passes through a surface. As in normal meter, the lux value was obviously a displayed value, and hardly used for embedded application as well as for lighting monitoring considering its expensive price. This limits the lighting monitoring in certain critical field. Therefore, in this paper, we present our initial works on the development of a webcam based lux meter that is applicable and suitable for lighting monitoring as well as the ability to be used in embedded application.

1.7                                           LIMITATION OF THE PROJECT

1. The LDR luxmeter is not incredibly accurate, but can be good enough in some conditions.
2. During LDR characterization, it is very important to ensure the light falling on the LDR and commercial sensor is identical.

• The LDR luxmeter is cheap and easy to make.  You only need one commercial light sensor to help you make as many LDR light sensors as you want.

1.8                                                   RESEARCH QUESTION

1. How does LDR measure light intensity?
2. Which type of resistor is used for measuring the intensity of light?

• What is the output of LDR Sensor?

1. How does an LDR work? What is the use of a lux meter?
2. What are the principles of a lux meter?
3. What is a lux meter?

• How does a lux meter work?
• What is lux meter and how does it operate?

1.9                                                        METHODOLOGY

To achieve the aim and objectives of this work, the following are the steps involved:

1. Study of the previous work on the project so as to improve it efficiency.
2. Draw a block diagram.

• Test for continuity of components and devices,

1. Design of the device was carried out.
2. Studying of various component used in circuit.
3. Construction of the circuit was carried out. The construction of this project includes the placing of components on Vero boards, soldering and connection of components,

• Finally, the whole device was cased and final test was carried out.

1.10                                                      PROJECT ORGANISATION

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.