MINI PROJECT PRESENTATION

AUTOMATIC TEMPERATURECONTROLLED FAN

Student 1Student 2Student 3Student 4

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Mini project byStudents of College name, xxxxxx

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INTRODUCTION

Ordinary fan regulators Electronic fan regulators

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Why automatic temperature controlled fan?

*Automatic speed control*Low power loss*Reduce Current Consumption*Allows fan to ramp up or down smoothly to new speed*Increase Fan Life*A single temperature or all temperatures can control the fan speed.*Small size and economic

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Lm35 temperat

ure sensor

ADCMicrocontr

oller(pic16f72/

3

RPS

Driver circuit PWM

Increase intemperature

BLOCK DIAGRAM

AC supply230 V, 50Hz

12v dc fan

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Components Used

*LM35*PIC Microcontroller*DC FAN & Driver circuit*Resistors* Diodes(bridge rectifier)*Capacitors*Regulator

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POWER SUPPLY

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RPS ?

Introductionyour collge name:

Embedded system requires a regulated power supply. This power supply circuit gives a variable regulated supply

Through an arrangement of voltage regulator 7805 and A regulated power supply is an embedded circuit; it converts unregulated AC into a constant DC. With the help of a rectifier it converts AC supply into DC. Its function is to supply a stable voltage (or less often current), to a circuit or device that must be operated within certain power supply limits. The output from the regulated power supply may be alternating or unidirectional, but is nearly always DC.

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REGULATED POWER SUPPLY

TRANSFORMER * A transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction. Electromagnetic induction produces an electromotive force within a conductor which is exposed to time varying magnetic fields. Transformers are used to increase or decrease the alternating voltages in electric power applications..

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Step down Transformer

Its secondary voltage is less than its primary voltage.

It is designed to reduce the voltage from the primary winding to the secondary winding.

The transformer converts high-voltage, low-current power into low-voltage, high-current power.

WHAT IS A BRIDGE RECTIFIER? A bridge rectifier is an arrangement of four or more

diodes in a bridge circuit configuration which provides the same output polarity for either input polarity. It is used for converting an alternating current (AC) input into a direct current (DC) output. A bridge rectifier provides full-wave rectification from a two-wire AC input, therefore resulting in lower weight and cost when compared to a rectifier with a 3-wire input from a transformer with a center-tapped secondary winding.

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TYPES OF BRIDGE RECTIFIERSyour collge name:

There are many different kinds of bridge rectifiers and at Future Electronics we stock many of the most common types categorized by maximum average rectified current, maximum reverse voltage, maximum peak current, forward voltage, packaging type and maximum reverse current. The parametric filters on our website can help refine your search results depending on the required specifications.

The most common sizes for maximum average rectified current are 1A, 1.5 A, 4 A, 25 A and 35 A. We also carry bridge rectifiers with maximum average rectified current as high as 1000 A. Forward voltage can range from 450 mV to 1.1 kV, with the most common bridge rectifier semiconductor chips having a forward voltage of 1.1 V or 1 V.

APPLICATIONS FOR BRIDGE RECTIFIERSyour collge name:

The primary application of bridge rectifiers is to transform an AC supply into DC power. All electronic devices require direct current, so bridge rectifiers are used inside the power supplies of almost all electronic equipment. Bridge rectifiers are also used for detecting the amplitude of modulated radio signals. The signal may be amplified before it is detected. If it is not, then a very low voltage drop diode or a diode biased with a fixed voltage must be used. Rectifiers are also used to supply polarized voltage for welding applications. Control of the output current is required in such circuits, and this may be achieved by replacing some of the diodes in a bridge rectifier with thyristors, which are diodes whose voltage output can be regulated by switching on and off with phase fired controllers.

FILTER(CAPACITOR)

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capacitor is two metal plates separated by something that does not pass electricity...[e.g: air].....So.....direct current [current flowing in only one direction, as from an ordinary battery] cant pass through as the electrons cant pass from one plate to another..But.. ac current[current constantly reversing its direction, as in the electricity supplied to your home] can pass through....this is because...since the current is constantly changing direction....a plate will become positive...then negative ..then positive..and so on...now although the electrons cant go through the air gap, the electric field produced by the charged plate can....and this changing electric field can alternatively pull and push electrons in the other plate...Thus, the ac current can be transferred from one plate to another. So......capacitors block dc but pass ac...and thus act as filters...

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A filter is a capacitor which filters out a certain frequency or range of frequencies from a circuit.

Usually capacitors filter out very low frequency signals.

These are signals that are very close to 0Hz in frequency value.

These are also referred to as DC signals.

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Voltage Regulator (LM 7805)

A voltage regulator is designed to automatically maintain a fixed voltage level.

7805 is a voltage regulator integrated circuit.

It is a member of 78xx series of fixed linear voltage regulator ICs.

The xx in 78xx indicates the fixed output voltage it is designed to provide.

7805 provides +5V regulated power supply.

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INDICATOR (LED)

a thing that indicates the state or level of something.

a device providing specific information on the state or condition of something, in particular

A light-emitting diode (LED) is a two-lead semiconductor light source. It is a p–n junction diode, which emits light when activated. When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons.

TEMPERATURE SENSORE LM35

 a sensor is an object whose purpose is to detect events or changes in its environment, and then provide a corresponding output. A sensor is a type oftransducer; sensors may provide various types of output, but typically use electrical or optical signals

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College of Engineering XXXXXXXXXXX

EMBEDDED SYSTEM

• An embedded system is a computer system with a dedicated function within a larger mechanical or electrical system, often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts . Embedded systems control many devices in common use today. Ninety-eight percent of all microprocessors are manufactured as components of embedded systems

OR • we can say that it is “A combination of computer hardware

and software, and perhaps additional mechanical or other parts, designed to perform a dedicated function. In some cases, embedded systems are part of a larger system or product, as is the case of an antilock braking system in a car ”.

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Significance

Due to their compact size, low cost and simple design aspects made embedded systems very popular and encroached into human lives and have become indispensable. They are found everywhere from kitchen ware to space craft. To emphasize this idea here are some illustrations.

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Embedded systems everywhere?Embedded systems span all aspects of modern life and there are many examples of their use.

a) Biomedical Instrumentation – ECG Recorder, Blood cell recorder, patient monitor system

b) Communication systems – pagers, cellular phones, cable TV terminals, fax and trans receivers, video games and so on.

c) Peripheral controllers of a computer – Keyboard controller, DRAM controller, DMA controller, Printer controller, LAN controller, disk drive controller.

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d) Industrial Instrumentation – Process controller, DC motor controller, robotic systems, CNC machine controller, close loop engine controller, industrial moisture recorder cum controller.

e) Scientific – digital storage system, CRT display controller, spectrum analyser.

Why a microcontroller ?A microcontroller is a single silicon chip with memory

and all Input/Output peripherals on it. Hence a microcontroller is also popularly known as a single chip computer. Normally, a single microcomputer has the following features :

Arithmetic and logic unit Memory for storing program EEPROM for nonvolatile data storage RAM for storing variables and special function registers Input/output ports

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Timers and counters Analog to digital converter Circuits for reset, power up, serial programming, debugging Instruction decoder and a timing and control unit Serial communication port

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What is inside an embedded system ?

Every embedded system consists of custom-built hardware built around a Central Processing Unit (CPU). This hardware also contains memory chips onto which the software is loaded. The software residing on the memory chip is also called the ‘firmware’.

The operating system runs above the hardware, and the application software runs above the operating system. The same architecture is applicable to any computer including a desktop computer. However, there are significant differences. It is not compulsory to have an operating system in every embedded system.

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For small appliances such as remote control units, air-conditioners, toys etc., there is no need fir an operating system and we can write only the software specific to that application. For applications involving complex processing, it is advisable to have an operating system.

In such a case, you need to integrate the application software with the operating system and then transfer the entire software on to the memory chip. Once the software is transferred to the memory chip, the software will continue to run for a long time and you don’t need to reload new software .

The next slide shows the layered architecture of an embedded system.

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Layered architecture of an Embedded System

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Classification of Embedded Systems

Based on functionality and performance requirements, embedded systems are classified as :

Stand-alone Embedded Systems Real-time Embedded Systems Networked Information Appliances Mobile Devices

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Stand-alone Embedded Systems

As the name implies, stand-alone systems work in stand-alone mode. They take inputs, process them and produce the desired output. The input can be electrical signals from transducers or commands from a human being such as the pressing of a button. The output can be electrical signals to drive another system, an LED display or LCD display for displaying of information to the users. Embedded systems used in process control, automobiles, consumer electronic items etc. fall into this category.

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Real-time Systems

Embedded systems in which some specific work has to be done in a specific time period are called real-time systems. For example, consider a system that has to open a valve within 30 milliseconds when the humidity crosses a particular threshold. If the valve is not opened within 30 milliseconds, a catastrophe may occur. Such systems with strict deadlines are called hard real-time systems.

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Languages for Programming Embedded Systems

1. Assembly language was the pioneer for programming embedded systems till recently. Nowadays there are many more languages to program these systems. Some of the languages are C, C++, Ada, Forth, and Java together with its new enhancement J2ME.

2. The presence of tools to model the software in UML, SDL is sufficient to indicate the maturity of embedded software programming

3. The majority of software for embedded systems is still done in C language. Recent survey indicates that approximately 45% of the embedded software is still being done in C language.

4. C++ is also increasing its presence in embedded systems. As C++ is based on C language, thus providing programmer the object oriented methodologies to reap the benefits of such an approach.

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1. C is very close to assembly programming and it allows very easy access to underlying hardware. A huge number of high quality compilers and debugging tools are available for the C language.

2. Though C++ is theoretically more efficient than C, but some of its compilers have bugs due to the huge size of the language. These compilers may cause a buggy execution.

3. C language can definitely claim to have more mature compilers C++. Now in order to avail the extra benefits of C++ and plus to avoid buggy execution, experts are doing efforts to identify a subset of C++ that can be used in embedded systems and this subset is called Embedded C++ .

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INTRODUCTION TO MICROCONTROLLER PIC16F72 AND ACCESSOREIS

MICROCONTROLLER: A Microcontroller is a Microcomputer in a single Chip. That

means that a microcontroller chip includes a microprocessor (CPU) as well as some often used peripherals. A controller is used to control some process or aspect of the environment. A typical microcontroller application is the monitoring a house. As the temperature rises, the controller causes the windows to open If the temperature goes above a certain threshold, the air conditioner is activated .

As the process of miniaturization continued, all of the components needed for a controller were built right onto one chip. A one chip computer or microcontroller was born. A microcontroller is a highly integrated chip, which includes, on one chip, all or most of the parts needed for a controller. The microcontroller could be called a “one-chip-solution”. It typically includes:

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CPU (Central Processing Unit or the microprocessor) EEPROM / EPROM / PROM / ROM (Read Only Memory for the

program code) RAM (Random, Access Memory for the program code) I /O (Input / Output) devices (serial, parallel, ADC, DAC etc.) Timers Interrupt controller Embedded Controller ADC Calculator PWM function generator

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TYPES OF PROGRAMMABLE INTEGRATED CIRCUIT (PIC)

Base-line: 12-bit Instruction Word length

Mid-Range: 14-bit Instruction Word length

High-End: 16-bit Instruction Word length

PIC MICROCONTROLLER ARCHITECTURE:

• Harvard architecture• Long Word Instructions• Single Word Instructions .Single Cycle

Instructions .Instruction Pipelining• Reduced Instruction Set• Register File Architecture• Orthogonal (Symmetric) Instructions

The high performance of the PIC micro TM devices can be attributed to a number of architectural features commonly found in RISC microprocessors.

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Only 35 single word instructions to learn All single cycle instructions except for program

branches, which are two-cycle Operating speed: DC - 20 MHz clock input DC - 200 ns

instruction cycle 2K x 14 words of Program Memory, 128 x 8 bytes of

Data Memory (RAM) Pin out compatible to PIC16C72/72A and PIC16F872 Interrupt capability Eight-level deep hardware stack Direct, Indirect and Relative Addressing modes

HIGH PERFOTMANCE RISC CPU

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PERIPHERAL FEATURES

High Sink/Source Current: 25 mATimer0: 8-bit timer/counter with 8-bit prescalerTimer1: 16-bit timer/counter with prescaler, can be incremented during SLEEP via external crystal/clockTimer2: 8-bit timer/counter with 8-bit period register, prescaler and postscalerCapture, Compare, PWM (CCP) moduleCapture is 16-bit, max. resolution is 12.5 nsCompare is 16-bit, max. resolution is 200 nsPWM max. resolution is 10-bit8-bit, 5-channel analog-to-digital converterSynchronous Serial Port (SSP) with SPI™ (Master/Slave) and I2C™ (Slave)Brown-out detection circuitry for Brown-out Reset (BOR)

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CMOS TECHNOLOGY

Low power, high speed CMOS FLASH technologyFully static designWide operating voltage range: 2.0V to 5.5VIndustrial temperature rangeLow power consumption:- < 0.6 mA typical @ 3V, 4 MHz20 μA typical @ 3V, 32 kHz< 1 μA typical standby current

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Features:o 300RPM 12V DC motors with Gearboxo 3000RPM base motoro 6mm shaft diameter with internal holeo 125gm weighto Same size motor available in various rpmo 0.35kgcm torqueo No-load current = 60 mA(Max), Load current = 300 mA(Max)

An electric motor is an electrical machine that converts electrical energy into mechanical energy. The reverse of this would be the conversion of mechanical energy into electrical energy and is done by an electric generator.

DC MOTOR

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Working Principle Of A DC MotorA motor is an electrical machine which converts

electrical energy into mechanical energy. The principle of working of a DC motor is that "whenever a current carrying conductor is placed in a magnetic field, it experiences a mechanical force". The direction of this force is given by Fleming's left hand rule and it's magnitude is given by F = BIL. Where, B = magnetic flux density, I = current and L = length of the conductor within the magnetic field.

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Project schematic diagram

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Personal computers

Exhaust fans in large hotels

Washing machines

CD and DVD players

APPLICATION

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Advantages and disadvantagesAdvantages:(1)Since it is an automated system ,it is programmed

effectively so that no interruptions would stop its functionality.

(2) To monitor the environment, that is not comfortable or possible to monitor for humans(especially for extended periods of time Prevents waste of energy.

Disadvantages-

(1) It can only be maintained by technical person . (2) Due to temperature variation, after sometimes it’s efficiency may be decreased.

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CONCLUSION AND RESULT

After designing, simulating, assembling, soldering and testing the circuit, we came to the conclusion that our circuit of the temperature based fan speed controller is working satisfactorily.

The construction hardware perfect. The total project work perfectly and has negligible amount of unexpected

functioning. The problem statement is implemented. Hardware part is halfway implemented. Through simulations and after running the code in IDE abstract is verified As the technology is going on developing day by day, we prefer things to be

done automatically and in the same way our projects reduces the work to mankind.