DESIGN AND CONSTRUCTION OF MICROCONTROLLER BASED DOMESTIC REMOTE CONTROL SYSTEM

CHAPTER ONE

1.0       INTRODUCTION

Fan is an unavoidable electrical appliance in our day to day life. While basic fan has evolved very little, the methods of controlling its speed have change vastly, from bulky regulators using resistances, to the present day miniature solid state regulators.

In our paper, we have devised a method to control the fan using a remote. Though they have Leen ways to control speed using remote, the novelty of our method lies in the fact that any kind of remote can be used to control its speed.

For example, consider a TV remote. Just like the fan, a TV is also considered a basic necessity nowadays. And if there is a TV, there is a remote.

These remote can be used to control the fan speed. Thus it is a universal method. This innovation is highly recommendable for elder people, who have problems like arthritis, and cannot walk to the switch board to change the speed. It is also a great benefit to sick people.

Remote control facilities the operation of fan regulators around the home or office from a distance. It provides a system that is simple to understand and also to operate, a system that would be cheap and affordable, a reliable and easy to maintain system of remote control and durable system irrespective of usage. It adds more comfort to everyday living by removing the inconvenience of having to move around to operate a fan regulator. The system seeks to develop a system that is cost effective while not under mining the need for efficiency. The first remote control, called boneset was developed in 1950 by Zenith Electronics Corporation (then known as Zenith Radio Corporation). He devices  was developed quickly, and it was called “Zenith Space Command”, the remote went into production in the fall of 1956, becoming the first practical wireless remote control device.

Today, remote control is a standard on other consumer electronic products, including VCR cable and satellites boxes, digital video disc players and home audio players. And the most sophisticated TV sets have remote with as many as 50buttons. In year 2000, more than 99 percent of all TV set and 100 percent of all VCR and DVD players sold are equipped with remote controls. The average individual these days probably picks up a remote control at least once or twice a day.

Basically, a remote control works in the following manner. A button is pressed. This completes a specific connection which produces a Morse code line signal specific to that button. The transistor amplifies the signal and sends it to the LED which translates the signal into infrared light. The sensor on the appliance detect the infrared light and reacts appropriately. The remote control’s function is to wait for the user to press a key and then translate that into infrared light signals that are received by the receiving appliance. The carrier frequency of such infrared signals is typically around 36kHz. Usually, the transmitter part is constructed so that the transmitter oscillator which drives the infrared transmitter LED can be turned on/off by applying a TTL (transistor-transistor logic) voltage on the modulation controlled input. On the receiver side, a photo transistor or photodiode takes up the signals.

1.1       AIMS AND OBJECTIVES

The objective of putting up this project, therefore, is to design equipment that can facilitate a convenient and easy way of controlling our electric fan, especially in powering them, without always going to appliances physically by ourselves.

This objective will be accomplished using various components which include a microcontroller (AT89C51) and NE555 IC which acts as the backbone of the project together with other components.

There is a trigger signal from the preceding blocks. While, for the first multi vibrator, trigger is sent from the IR receiver, for the second multivibrator, trigger is sent from the Opto-coupler.

CHAPTER TWO

2.0       LITERATURE REVIEW

During British rule, the word came to be used in a special sense by Anglo-Indians to mean a large swinging fan, fixed to the ceiling, and pulled by a servant, called Punkawallah.

In the 17th century, the experiments of scientists like Otto Von Guericke, Robert Hooke and Robert Boyle, elucidated the principles of vacuum and airflow. The English architect Sir Christopher Wren applied an early ventilation system in the Houses of Parliament that used bellows to circulate the air. The Houses of Parliament would be the catalyst for much later improvement and innovation. John Theophilus Desaguliers, a British engineer, demonstrated a successful use of a fan system to draw out stagnant air from the coal mines in 1727 and soon afterwards he installed a similar apparatus in Parliament.

In 1849, a 6m radius steam driven fan, designed by William Brunton, was made operational in the Gelly Gaer Colliery of South Wales. The model was exhibited at the Great Exhibition of 1851. Improvements in the technology were made by Jame Nasmyth, Frenchman Theophile Guibal and J.R. Waddle. Between the years 1882 and 1886, New Orleans resisdent Schuyler Skaats Wheeler invented a fan powered by electricity. It was commercially marketed by the American firm Crocker and Curtis Electric Motor Company. In 1882, Philip Diehl introduced the electric ceiling fan. Heat-convection fans fueled by alcohol, oil or kerosene were common around the turn of the 20th century.

In the 1920s, industrial advances allowed steel fans to be mass produced in different shapes, bringing fan prices down and allowing more homeowners to afford them. In the 1930s, the first art deco fan (the “swan fan”) was designed.

In the 1950s, fans were manufactured in colours that were bright and eye catching. Central air conditioning in the 1960s caused many companies to discontinue production of fans. In the 1970s, Victorian-style ceiling fans became popular.

In 1998, Walter K. Boyd invented the HVLS ceiling fan, Boyd developed a slow moving fan with a very large 8-feet diameter. Due to its size, the fan moved a large column of air down and out 360 degrees and continuously mixed fresh air with the stale air inside the barn. They are used in many industrial settings, because of their energy efficiency.

By the early 2000s, the number of consumer electronic devices in most homes greatly increased. According to the Consumer Electronics Association, an average American home has four remotes. To operate a home theater as many as five or six remotes may be required, including one for cable or satellites receiver, VRC or Digital Video Recorder, DVD player, TV and audio amplifier. Several of these remotes may need to be used sequentially, but, as there are no accepted interface guidelines, the process is increasingly cumbersome. Many specialists, including Jakob Nielsen, a renowned usability specialist and Robert Alder, the inventor of the modern remote, note how confusing, unwieldy and frustrating the multiplying remotes have become.

Most modern remote control alert systems for appliances use infrared diode to emit a beam of light that reaches the device or equipment.

Therefore the concept of remote control is further expanded in another form by applying it in a circuit that is used to power many appliances automatically by pressing buttons on the remote control.

COUNTER MODULE

            It consists of a CD4017 decade counter IC. It has one input pin, ten outputs pins from Q0 to Q9 and one reset pin. Here, we are using the outputs Q0 – Q4, and shorting Q6 and reset pins. The outputs Q0-Q4 are routed to the threshold-discharge pins of the second multivibrator via a resistor and capacitor network. The resistances R5-R9 and the capacitance C5 fix the output pulse width of the multivibrator .

            OPTO-ISOLATION

The main purpose of an Opto-isolator is to prevent the high voltages or rapidly changing voltages on one side of the circuit from damaging components or distorting transmissions on the other side. In our project we use a MOC3021 Opto-isolator IC to control the 230V AC voltage on the load using a low voltage signal from the second multivibrator. However, the two stages have a complete electrical isolation.

            OPTO-COUPLER

It is essentially an Opto-isolator, but functioning as zero detector. It sends out pulses when it detects a zero crossing on the stepped down input 12V AC line. These pulses are used to trigger the second multivibrator. We use the Opto-coupler IC MC2TE.

            VOLTAGE REGULATOR

We need a low voltage for power supply to entire low voltage control circuit. We step down the 230V AC to 12V-0-12V using a centre tapped transformer. This voltage is rectified to DC and using a LM7809 IC, converted to 9V DC which is used to power the control circuitry.

            SRC MODULE

            We are using a BT136 triac to control the fan speed, using the MOC3021 Opto-isolator to trigger it. Since we do not have any beforehand experience of working with 230V AC, the application circuit is as directed by manufacturers on their datasheet with little modification.

2.1       ELECTRONICS COMPONENTS

The components used in construction of the remote control fan regulator are listed explained below.

2.2       RESISTOR

A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. The current through a resistor is in direct proportion to the voltage across the resistor’s terminals. This relationship is represented by Ohm’s law: R=V/I. The function of a resistor is to resist the flow of electric current in an electronic circuit. Resistors are classified into two classes of resistors; fixed resistors and the variable resistors. A resistor is made of either carbon film or metal film. Its SI unit is (ohms) Ω

         Fig 2.1 A Resistor

                  Fig 2.2 Electronic Symbol of Resistor

2.3       LIGHT-EMITTING DIODE (LED)

A light-emitting diode (LED) is a semi-conductor light source. When a light-emitting diode is switch on, electrons are able to recombine with holes within the device, releasing energy in the form of photons. An LED is often small in area (Less than 1 mm 2), LED has many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved physical robustness, smaller size and faster switching

Anode                      Cathode

                               Fig 2.3 Electronic Symbol of a LED

The secondary winding. Transformer can be used to vary the relative voltage of circuit or isolate them, or both. It ranges in size from thumbnail-sized used in microphones to units weighing hundreds of tons interconnecting the power grid. A wide range of transformer designs are used in electronic and electric power applications. Transformers are essential for the transmission, distribution, and utilization of electrical energy.

Primary Winding                      Secondary Winding

Fig 2.6 Circuit Symbol of a transformer

2.4       DIODES

Diodes are semiconductor devices which allow the passage of current in one direction only. The latter part of that statement applies equally to vacuum tube diodes. Diodes however are far more versatile devices than that. They are extremely versatile in fact.

Diodes can be used as voltage regulators, tuning devices in if tuned circuits, frequency multiplying devices in rf circuits, mixing devices in rf circuits, switching applications or can be used to make logic decisions in digital circuits. There are also diodes which emit “light”, of course these are known as light-emitting-diodes or LED’s. as we say diodes are extremely versatile.

Schematic Symbols for Diodes

A few schematic symbols for diodes are:

k

a

Diode     Zener      Varactor      Vacuum Tube                  LED

diode      diode                   diode

                        Figure 2.7 Schematic symbols for diodes

2.5       CAPACITOR

A capacitor is originally known as a condenser. It’s a passive two terminal electrical component used to store energy electro statically in an electric field. An ideal capacitor is characterized by single constant value, capacitance. This is the ratio of the electric charge on each conductor to the potential difference between them. The SI unit of capacitance is the farad which is equal to one coulomb per volt.

Capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass. In analog filter networks, they smooth the output of power supplies. In resonant circuits they tune radios to particular frequencies. In electric power transmission systems they stabilize voltage and power flow.

       Fig 2.8 A Capacitor

                                                Fig 2.9 Schematic Symbols for diode

2.6       TRANSISTOR

Transistor can be regarded as a type of switch, as can many electronic components. They are used in a variety of circuits and you will find that it is rare that a circuit built in a school Technology Department does not contain at least one transistor. They are central to electronics and there are two main types; NPN and PNP. Most circuits (e.g. this project design) tend to use NPN. There are hundreds of transistors which work at different voltage but all of them fall into these two categories.

There are two types of standard transistors, NPN and PNP, with different circuit symbols. The letters refers to the layers of semiconductor materials used to make the transistor. Most transistors used today are NPN because this is the easiest type to make from silicon. This page is mostly about NPN transistors.

B                                B

E                                E

Fig 3.17 Transistor circuit symbols