Design And Construction Of A Microcontroller Based Temperature Indicator

ABSTRACT

This work is on temperature control indicator. Temperature control indicator is a device that measures temperature or indicate temperature gradient using a variety of different principles. Temperature control indicator is designed to maintain a constant temperature by the use of a thermostat. This study provides an opportunity to learn using sensors to measure the real world signals that are analog in nature. This work is based on a PIC16F688 microcontroller and an LM35 temperature sensor. LM35 is an analog sensor that converts the surrounding temperature to a proportional analog voltage. The output from the sensor is connected to one of the ADC channel inputs of the PIC16F688 microcontroller to derive the equivalent temperature value in digital format. The computed temperature is displayed in a 16×2 character LCD, in both °C and °F scales. Inside and outside room temperature are used in the controller design.

TABLE OF CONTENTS

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      PROBLEM STATEMENT

1.6      PURPOSE OF THE PROJECT

CHAPTER TWO

2.0      LITERATURE REVIEW

2.1      OVERVIEW OF TEMPERATURE CONTROLLER

2.2      REVIEW OF DIFFERENT TYPES OF TEMPERATURE CONTROLLER AND THEIR WORKING PRINCIPLE

2.3     DEFINITION OF TEMPERATURE SENSOR

2.4    TYPES OF TEMPERATURE SENSORS

CHAPTER THREE

3.0      DESIGN METHODOLOGY

3.1      SYSTEM BLOCK DIAGRAM

3.2      SYSTEM CIRCUIT DIAGRAM

3.3      CIRCUIT WORKING PRINCIPLE

3.4     SENSOR THEORY

3.5    SYSTEM SOFTWARE AND CODE

3.6      DESCRIPTION OF COMPONENTS USED

3.7      POWER SUPPLY

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

The main purpose of this Digital Temperature indicator is to indicate or display the temperature of a device  such as incubator or any other device like AC or any other electronic devices whose temperature keeps fluctuating and thus requires a constant watch on the device. The use of this system eliminates constant watching on the device by self controlling the temperature of the system.

Temperature control indicator it is an apparatus consisting of a box designed to maintain a constant temperature by the use of a thermostat; used in incubators for chicks or premature infants. In the business world, temperature indicator used in incubator is an enterprise that is set up to provide office space, equipment, and sometimes mentioning assistance and capital to new businesses that are just getting stated. (the tem is familiar in poetry farming, where an incubator is a specially – equipped home for baby chickens)> business incubators are set up by universities, non-profit groups, and increasingly by venture capitalists, especially for new web businesses.

Our proposed project consists of digital temperature sensors for more accurate temperature display. This system overcomes the disadvantages of thermostat/analog systems in terms of accuracy. This system can be used in any firm or organization where it is very important to maintain precise temperatures. LCD display is used to display the temperature and when the temperature exceeds the set limit, the heating element is switched off in order to control the temperature. After the heating element is switched off, it remains OFF until the temperature reaches below the exceed limit. Thus the system keeps on switching ON/OFF the heater or the AC for automatically controlling the temperature of the system. The system uses a digital temperature sensor in order to detect temperature and pass on the data to the microcontroller. The pic microcontroller processes data and sends the temperature to be displayed on LCD screen. The display consists of 7 segment display unit to display up to 4 numbers.
It consists of 4 push buttons for setting the high and low temperatures. Pressing set button allows user to increment and decrement high and low temperatures. After that the system detects temperature and switches the load when it goes beyond set limits.

1.2                                         BACKGROUND OF THE PROJECT

Nowadays, the temperature control indicator used in incubator is widely used especially by farmers – to hatch their egg and by doctors – to incubate their patient’s pre-mature babies. Usually the conventional incubator is always heating the room depending on the fixed temperature setting and is not automatically adjusted by the users. In the central air conditioning control field, excellent real-time, high reliability, and good intelligence are proposed by many researchers. The traditional PID algorithm is, in fact, still playing a main role in the control process. The incubator system has becoming a field to be researched to improve the user convenience by applying intelligent system such as THERMOCOUPLE.

While the enhanced incubator system is being designed, the consideration of the type of control system must be included in a modeling design. In particular the controller must be able to avoid the inefficiency of having the air conditioning operate all the time. Several control options were considered at presence sensing circuit, which would turn the incubator off when nothing not in the room with the temperature sensor input, which would change the incubator operation depending on room temperature [1]. Based on the observation of the using the present conventional air conditioning application, it always working all the time without a systematic control. Therefore, the control of the incubator is adjusted through a feedback control system to monitor and maintain a constant temperature based on the data input from the sensor.

1.3                                            OBJECTIVES OF THE PROJECT

The objectives of this project are:

• To find the mathematical model of a temperature control indicator system.
• To design a controller using temperature sensor.
• To analyses the performance of the
• Real-time temperature is displayed on its LCD screen.

1.4                                                                              PROBLEM STATEMENT

The problem happens when the incubator is still functioning although in the event of cold weather. The function is uncontrolled and must be manually turned on and off. Sometimes it can lead to high usage of electricity which in turn raises the electricity bill when the user forgot to switch it off. The system also does not have the capacity to indicate in order to adjust the room temperature regardless of the ambient temperature. To address the problem, the temperature control indicator that can indicate the temperature automatically is proposed. The advantages of such a system are less energy usage, and provides more convenient to the consumers.

1.5                                            PURPOSE OF THE PROJECT

The main purpose of this Digital Temperature indicator is to display the temperature of devices such as incubator or any other electronic devices like oven whose temperature keeps fluctuating and thus requires a constant watch on the device.

1.6                                                 SCOPE OF THE PROJECT

Below are the scopes of the project:

This study provides an opportunity to learn using sensors to measure the real world signals that are analog in nature. This work is based on a PIC16F688 microcontroller and an LM35 temperature sensor. LM35 is an analog sensor that converts the surrounding temperature to a proportional analog voltage. The output from the sensor is connected to one of the ADC channel inputs of the PIC16F688 microcontroller to derive the equivalent temperature value in digital format. The computed temperature is displayed in a 16×2 character LCD, in both °C and °F scales. Inside and outside room temperature are used in the controller design.

The analysis controller performance in terms of automatic temperature indicator based temperature needed.

1.7                                          APPLICATION OF THE PROJECT

this device can be used for temperature control electrical appliances such as:

1. Air conditioner
2. Refrigerator

• Fan,

1. Furnace etc.