ABSTRACT
The objective of this research work is to design and implement a microcontroller – based digital time aware oven temperature controller and display. Various kinds of oven exist for various purposes: electrical, gas and manual types for either home use or industrial purposes. The research is achieved using the AT89C51 Microcontroller which compares the oven temperature with the preset temperature to determine when to turn ON or OFF the oven, the transistorized Relay which switches ON and OFF the oven depending on the logic signal sent by the microcontroller and the LM35 which is a temperature sensor that senses or determines the oven temperature. It works with the LM358 which amplifies the picked signal and which also does the conversion (voltage to pulse width) and sends to the microcontroller for processing, it also has push buttons for setting the preset temperature and indicators showing the status of the oven. The accuracy of the microcontroller – based time aware oven temperature controller makes it more reliable as a particular temperature which a particular meal is expected to cook and be okay could be set.
CHAPTER ONE
A microcontroller based time aware oven is an automatic time control oven/cooker that monitors a preset time and regulates the oven/cooker temperature over the set time [2, 12]. If the temperature of the oven increases or reaches the set maximum, the heating element is automatically turned off, but when the temperature reduces, the heating element is also automatically turned on. This on and off activity takes place within the set time given to the controlling unit, say five minutes, and when the time runs out, the oven is automatically turned off. This is because the oven is a time conscious system. The research has an electric oven with a heating element as the heat source; it also has a microcontroller system. The system uses a temperature sensor LM35 to determine the ambient temperature surrounding the oven. An oven is an enclosed compartment for heating, baking or drying. It is most commonly used in cooking and pottery. Two common kinds of modern ovens are gas ovens and electric ovens. Ovens used in pottery are also known as kilns. An oven/cooker used for heating or for industrial processes is called a furnace or industrial oven [6, 10].
In cooking, the conventional oven is a kitchen appliance and is used for roasting and heating. Food normally cooked in this manner includes meat, casseroles and baked goods such as bread, cake and other desserts. In the past, cooking ovens were fueled by wood or coal. Modern ovens are fueled by gas or electricity. When an oven is contained in a complete stove, the burners on the top of the stove may use the same or different fuel than the oven [5, 7, 8].
Some ovens have a full logic system that can start and end the cooking process for you so you can simply set and forget [1, 3, 11]. To keep plates and food warm ready for serving, some ovens offer optional warming racks. If you want to enjoy roasts the low-fat way consider adding a rotisserie option to your new oven. A defrosting feature can help you thaw frozen food quickly.
1.1 BACKGROUND OF THE PROJECT
Energy has been identified as an indispensable factor that enhances the socioeconomic development of a country (Rahman, M. M. et al) 2012. Socio-economic prosperity is said to dependent largely upon energy conservation (Yong, K. P et al). Satisfying the need of required energy to be consumed in any given society will require that while the Government and private organizations are making effort to generate sufficient electricity, as much as possible the citizenry must devise means for optimum utilization (Rahman, M. M. et al) 2012. Most electric cookers available today lack the vital aspect of control, which has led to several losses ranging from food burning, power wastage, human losses etc. This among other factors has inspired the need of integrating control in electric cookers in a bid to reduce to the barest minimum or completely eliminate some these losses. The major parameters that can often be controlled in an electric cooker or oven are the cooking temperature and time.
Generally, control of temperature and time can be realized in two ways; either using analogue designs or digital designs. Analogue designs generally make use of simple timers and thermostats to regulate the time and temperature respectively where as digital designs make use of components such as microcontrollers, sensors, integrated circuits etc.
Digital designs generally offer the advantages of more precision and accuracy, cheaper cost, less susceptibility to noise and interference from the circuit, easy troubleshooting, more flexibility etc over analogue designs (Bany Wooland G) 1984.
1.2 OBJECTIVE OF THE PROJECT
The objective of this research work is to design and implement a microcontroller – based digital time aware oven temperature controller and display.
1.3 PURPOSE OF THE PROJECT
The purpose of the design and construction work is to understand the working principle of electric cookers with timer, temperature control and display. It is also important to determine the thermal capacities of various materials and the compatibility to serve as heating element.
1.4 SIGNIFICANCE OF THE PROJECT
This project work is intended to serve as a catalogue and manual for the construction, installation, maintenance and repair of different possible faults in electric cookers, it is also of a great benefit to the department and society as it will serve as medium of knowing the principle of operating the model work. It serve as an alternative means for cooking instead of using the gas cooker, solar cooker and the firewood.
1.5 SCOPE OF THE PROJECT
There is no upper limit to the temperature obtained except the ability of the material to with stand heat. This work was achieved using the AT89C51 Microcontroller which compares the oven temperature with the preset temperature to determine when to turn ON or OFF the oven, the transistorized Relay which switches ON and OFF the oven depending on the logic signal sent by the microcontroller and the LM35 which is a temperature sensor that senses or determines the oven temperature. It works with the LM358 which amplifies the picked signal which does the conversion (voltage to pulse width) and sends to the microcontroller for processing, it also has push buttons for setting the preset temperature and indicators showing the status of the oven.
1.6 DELIMITATION OF THE PROJECT
1. There is freedom of location and general adaptability.
2. It entails good cooking condition, cleanliness, quietness and ambient temperature.
3. Uniform of temperature within narrow limit.
4. Capital cost, running and maintenance cost of electric cooker are low.
5. There are no deposits of ash carbon dirt in an electric cooker.
1.7 LIMITATION OF THE PROJECT
1. It cannot be used were there is no electricity, since it make use of electrical energy.
1.8 DEFINITION OF TERMS
THERMOSTAT: This is an electrical device design to heat up bend and open the circuit when excessive current flows and close the circuit when the heat reduces. It can also be defined as an automatic regulator that control the amount of current that heat up the circuit.
HEATING ELEMENT: This is a conductor material that is designed to heat up when connected to current flow. It converts electric energy into heat energy.
OUTLET PLUG: This is an electrical device design with two or three metal pins that fit into holes in a socket to make an electrical connection.
SWITCH: This is a device used to connect or break the flow of electric current in a circuit.
INDICATOR (LAMP): This is a device which glows like a bulb indicating the working status of a connection.
CABLE: A cable is a material or conductor use in conveying electric current from one point to another.
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 an electric cooker. In this chapter, the background, significance, objective limitation and problem of an electric cooker were discussed.
Chapter two is on literature review of an electric cooker. 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 reference
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