Description
ABSTRACT
This work presents the construction of a light dimmer circuit that utilizes the current-regulating properties of a triac. Prior to being triggered, the triac provides a barrier in the circuit, preventing current flow from a 220V AC source through the light bulb. During this time voltage across a capacitor within in the circuit builds up until it exceeds the breakover voltage of a diac. Once the breakover voltage is exceeded, the diac “fires” the triac into a conducting state and current flows through the light bulb. The amount of voltage seen over the light bulb is determined by the firing angle of the triac which is set by the RC time constant of the circuit. This process then repeats every half cycle.
TABLE OF CONTENTS
COVER PAGE
TITLE PAGE
APPROVAL PAGE
DEDICATION
ACKNOWELDGEMENT
ABSTRACT
CHAPTER ONE
1.0 INTRODUCTION
1.1 BACKGROUND OF THE PROJECT
- AIM AND OBJECTIVE OF THE PROJECT
- PROBLEM STATEMENT
- PURPOSE OF THE PROJECT
- APPLICATION OF THE PROJECT
- SIGNIFICACE OF THE PROJECT
- LIMITATION OF THE PROJECT
- SCOPE OF THE PROJECT
- PROJECT ORGANISATION
- METHODOLOGY
CHAPTER TWO
LITERATURE REVIEW
- REVIEW OF THE STUDY
- HISTORICAL BACKGROUND OF THE PROJECT
- OVERVIEW OF TRIAC
- BASICS OF TRIAC
- CONSTRUCTIONAL REVIEW OF TRIAC
- WORKING AND OPERATION OF TRIAC
- VOLTAGE-CURRENT CHARACTERISTICS OF TRIAC
- ADVANTAGES OF TRIAC
- DISADVANTAGES OF TRIAC
- APPLICATION OF TRIAC
- DIFFERENCE BETWEEN SCR AND TRIAC
CHAPTER THREE
SYSTEM DESIGN METHODLOGY
- SYSTEM BUILDING BLOCK
- CIRCUIT DIAGRAM OF THE SYSTEM
- CIRCUIT DESCRIPTION
- SYSTEM CODE
- DESCRIPTION OF SYSTEM OPERATION TECHNIQUES
CHAPTER FOUR
- TESTING AND RESULTS
- CONSTRUCTION PROCEDURE AND TESTING
- INSTALLATION OF THE COMPLET DESIGN
- ASSEMBLING OF SECTIONS
- TESTING OF SYSTEM OPERATION
- RESULT
CHAPTER FIVE
- CONCLUSION AND RECOMMENDATION
REFERENCE
CHAPTER ONE
1.0 INTRODUCTION
Dimmers of various types are well known in the prior art. Mechanical rheostats must dissipate considerable wasted energy in the form of heat and must be closely coordinated in resistive value with the load being controlled in order to achieve optimal dimming effect. Arduino dimmers are disadvantageous in that two devices in combination with an elaborate triggering arrangement are required in full wave AC applications. The arduino has been the device of choice in prior art line voltage AC dimmers due to its inherently high efficiency and load independence. The primary advantage of these prior art arduino-based line voltage AC dimmers is that they may be easily configured in series with an incandescent lighting load as a complete controller and load circuit. In this configuration, the dimmer derives operating power via loop interaction with the load it controls to thereby achieve the same two-wire hookup as a toggle switch, which it often directly replaces. Its high efficiency and minimal heat dissipation facilitate installation in a confined space, such as a wall electrical box that may be conveniently accessed.
AC line voltage is generally considered safe in outdoor applications when proper wiring procedures are followed and a safety device such as an isolation transformer and/or ground fault interrupter is added, voltage levels below 50 volts are considered non-shocking and are therefore often preferred in wet environments to eliminate even the slightest possibility of electrical shock.
1.1 BACKGROUND OF THE PROJECT
Saving of power is the main important criteria in the present world. In this project we are going to design the circuit to control the light intensity of bulbs automatically according to the sunlight intensity. Light dimming is based on adjusting the voltage which gets to the lamp. Light dimming has been possible for many decades by using adjustable power resistors and adjustable transformers. Those methods have been used in movie theatres, stages and other public places. The problem of those light controlling methods have been that they are big, expensive, have poor efficiency and they are hard to control from remote location.
Between 1960-1970 thyristors and triacs came to market. Using those components it was quite easy to make small and inexpensive light dimmers which have good efficiency. Electronics controlling also made possible to make them easily controllable from remote location. Solid-state light dimmers work by varying the “duty cycle” (on/off time) of the full AC voltage that is applied to the lights being controlled. For example, if the voltage is applied for only half of each AC cycle, the light bulb will appear to be much less bright than when it get the full AC voltage, because it gets less power to heat the filament. Solid-state dimmers use the brightness knob setting to determine at what point in each voltage cycle to switch the light on and off.
In this project the ac bulb intensity will vary according to the desire of the user using a potentiometer.
1.2 PROBLEM STATEMENT
Over intensity of light affect eyes and at the same consumes energy. We often adjust the display brightness of our mobile phones to suit to our need and saves energy of our phones. Light dimmer was built to solve this problem. With this project, bedside lamps or any other lighting intensity at home can be varied using arduino.
1.3 AIM AND OBJECTIVE OF THE PROJECT
The main aim of this work is to adjust the brightness of the lamp connected to the circuit by serial port. The brightness can be changed according to the commands we provide to the serial port of arduino. At the end of this work, student involved will be able to:
- regulate the intensity of a light using an AC wall outlet as a source using arduino.
- demonstrate the concept of a firing angle, α, and its relation to the RMS voltage applied to the light bulb
1.3 PURPOSE OF THE PROJECT
The main purpose of this work is to regulate the intensity of an AC lamp thereby saving energy via it using arduino
1.4 APPLICATION OF THE PROJECT
AC dimmers and, more particularly, to an arduino-based ac voltage dimmer for use in outdoor applications such as architectural lighting and swimming pool lighting.
1.5 SIGNIFICANCE OF THE PROJECT
The primary advantage of arduino based AC dimmers is that they may be easily configured in series with an incandescent lighting load as a complete controller and load circuit. In this configuration, the dimmer derives operating power via loop interaction with the load it controls to thereby achieve the same two-wire hookup as a toggle switch, which it often directly replaces. Its high efficiency and minimal heat dissipation facilitate installation in a confined space, such as a wall electrical box that may be conveniently accessed.
1.6 LIMITATION OF THE PROJECT
The problem of arduino-based line voltage AC dimmers is the generation of a relatively high level of undesirable radio frequency noise that results from the inherently rapid switching time. Since triggering of these prior art dimming circuits does not occur until the AC voltage reaches at least 35 volts, it is only possible to achieve a maximum brightness level of about 90% of an incandescent lighting load, as compared to about 95% in the case of an arduino -based dimmer and 100% when employing a direct switching device. Yet another problem of arduino -based line voltage AC dimmers is the potential for light flickering and unwanted extinguishing of the incandescent lighting load at or near the maximum dimming level.
1.7 SCOPE OF THE PROJECT
Broadly, there is disclosed a dimmer circuit for varying AC power applied to a load from a supply. The dimmer circuit includes a bidirectional output switch connected in series between the supply and the load. The output switch comprises a pair of electronic switches connected back to back, the output switch conducting electricity in response to a trigger signal and turning itself off in response to power decreasing below a select holding level. Input means generate commands to selectively increase or decrease power applied to the load.
1.8 METHODOLOGY
To achieve the aim and objectives of this work, the following are the steps involved:
- Study of the previous work on the project so as to improve it efficiency.
- Draw a block diagram.
- Test for continuity of components and devices,
- Design and calculation for the device was carried out.
- Studying of various component used in circuit.
- Construction of the circuit was carried out.
- Finally, the whole device was cased and final test was carried out.
1.9 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.
CHAPTER TWO
LITERATURE REVIEW
CHAPTER TWO
2.0 LITERATURE REVIEW
The major component of this work is triac. This triac controls the current that dims the ac lamp. For this reason this chapter focuses on the reviewing light dimmer.
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