Bimedical Temperature and Heart Beat Monitor

7/30/2019 Bimedical Temperature and Heart Beat Monitor

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IN THE PARTIAL FULFILMENT OF THEIRREQUIREMENTS FOR THE AWARDS OF DIPLOMA IN

ELECTRONICS AND COMMUNICATION ENGINEERING

SUBMITTED TO

Er. RAJEEVSAPRA Mr. RAKESHMANCHANDA(HOD. ELECTRONICS) (PROJECT GUIDE)

SUBMITTED BY

SHRI KRISHAN

(070110540)


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ACKNOWLEDGEMENTCERTIFICATEINTRODUCTIONCIRCUIT DIAGRAMPCB LAYOUTPARTS LISTPCB DESIGNINGSOLDERING TECHNIQUEFUNCTION OF EACH ELECTRONICS

COMPONENT

WORKING OF CIRCUITSPRECAUTIONSBIBLIOGRAPHY


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ACKNOWLEDGEMENT

The satisfaction, which comes on completion of any task/

work/ project, would be great, but it is unmeaning without

thanking those people who gave us constant guidance,

knowledge and technical information about our project.

So, this is to thanks those people who helped us at every stage

and every difficulty which we faced in completion of our

Project so our first thanks goes to our project guides Mr.

RAKESH MANCHANDA their guidance and personal

supervision through out this project, Who helped us and

provide us every facility to have this pleasure that today we

submitted this project. We also want to thanks all the staff

members of ELECTRONICS DEPARTMENT OF

GOVERNMENT POLYTECHNIC, AMBALA CITY

for their co-operation.

SHR1 KRISHAN(070110540)


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This is certified that SHRI KRISHAN student of

ELECTRONICS & COMMUNICATION

ENGINEERING have been completed this project with my

knowledge. All the information provides in the project is

absolutely true. I here by declare that project on

MICROCONTROLLER BASED BIO-MEDICALHEART

BEAT AND TEMPERATURE MONITORING has been

tested and found up to the mark by me.

MR. --------------------

(Project Guide)

Er. -------------------

(HOD,ELECRTONICS)


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INTRODUCTION

Microcontroller Based Temperature and Heart Beat Read

used to measure temperature and Herat beat of the person in

contact. Microcontroller Based biomedical Temperature and

Heart Beat Read out are suitable for operation in a small

office/home environment for understanding, how data is read

by microcontroller.

The project use LM35 IC for sensing the temperature of the

human body, when any person touches (hold) the LM 35. The

IC converts the temperature value into the mV. The output of

the IC is directly given to microcontroller port. The software

of the microcontroller changes milivolt value into the

centigrade value and display on the LCD. The blood flow into

the finger can be sensed by photoelectrical method. For this

LED and LDR combination is used. As we know the LDR

changes its resistances depending upon the light intensity

falling on it. Hence this change of resistance affects the value

of current through the circuit. The small value of

photoelectric current amplified by dual operational amplifier

IC LM358 and amplified signal is given to microcontroller

and which depending upon the value of photoelectric current

shows the heart beat of the human on the LCD screen.


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CIRCUIT DIAGRAM


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PCB LAYOUT FOR PROJECT

PARTS LISTSEMICONDUCTOR


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IC1 Microcontroller PIC 16F877AIC2 LM35 temperature sensorIC3 7805 +5 volt regulatorIC4 ASK transmitterIC5 LM358D1-D4 1N4007 rectifier diodeLED1 Light emitting DiodeLDR1 Light dependent ResistorLCD1 Liquid crystal display

CAPACITORS

C 1000F,25V ELECTROLYTEC 0.1 F CERMIC DISKC 22 pF CERMIC DISKC 0.4 F CERMIC DISK

RESISTORS (- WATT, 5% CARBON)

R 220 OHMR 100 KR 10 KR 2.0 KR 01 KR 47 K

R 10 K

MISCELLANEOUS

XTAL - 4 MHz quartz crystalS1 - PUSHTO-ON SWITCHTransformer 12v/300 mAPCB


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PCB DESIGNING

A printed circuit board popularly known, as PCB does a

special photoengraving process print a complete layout

diagram of an electronic circuit consisting of conducting path

in? on the other side of the PCB are mounted electronics

component like Resistor, Capacitor, Coils, Transformers,

Transistors, Diodes and ICs. Suitable holes are punched in

the PCB for mounting the components, which are connected

to the connecting paths by soldering. The PCB board is made

of a translucent material and with a bright light on one side.

The circuit on the opposite side can be easily traced. Printed

circuit boards are extensively used for assembling electroniccircuits particularly those using semiconductor devices like

transistor and ICs. Use of PCBs makes the circuit assembly

more compact, uniform and stable than the one using hand

wiring PCB assembly also lends itself efficiently to mass

production methods. The different processes that take placein the fabrication of a PCB are as follows

1. Layout designing2. Art work designing3. Transfer of conductor pattern on copper clad sheet.4. Printing of ETCH resist material on conductor pattern5. Drying & etching


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6. stripping7. Drilling8. Surface cleaning9. Final inspection of PCB

1)LAYOUT DESIGNING:First of all the layout design of the circuit, which is to be

traced on the PCB, is prepared. The layout of PCB has to

incorporate all the information on the Board before one can

go on to the art work preparation. The detailed circuit

diagram is very important for the layout designer but he must

familiar with design concept and the philosophy behind the

equipment. In this process the layout designer, tracing the

circuit on a graph paper. By this process he marks where thehole should be. Thus the circuit which to be traced on the

PCB is firstly traced on the graph paper or its layout is

designed. In layout designing the distance between the copper

tracks and lengths, size etc. of components are also taken

consideration.2)ART WORK DESIGNING:

From the layout design of the circuit, the art work design is

prepared. Art work the drawing, showing conductor pattern

on the PCB. After testing the prototype a rough layout is

prepared on the millimeter graph paper. Artwork of thecircuit is prepared on transparent paper with sticking tapes


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and Pads. Tapes serve as conductor paths while pads serve as

areas for mounting component leads.

3)TRANSFER OF CONDUCTOR PATTERN ONCOPPER CLAD

After designing the art work on the graph paper, we transfer

it on to the trace paper. The conductor pattern is then

transferred on to the copper clad laminate with the help of a

carbon paper. This transfers the pattern on the copper clad

laminate.

4)PRINTING OF ETCH RESIST MATERIALON CONDUCTOR PATTERN

The conductor pattern on the copper clad laminate can beprinted by paint which are etch resist material. This resist

material is painted on the track so that we can obtain the

conductor parts at the desired places and rest of the copper

removed after etching. After painting the PCB, the entire

PCB is inspected so that there are no short circuit betweenthe two different tracks and open circuit within the same

track.

5)DRYING & ETCHINGAfter drying, etching is done to remove all unwanted copper,

which is present on the portion other than the pattern onPCB. For the PCB is kept dipped in solution of ferrous


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chloride and two or three drops of HCL. Chemical react with

the copper and dissolve it. After some hours we get the PCB

left only copper tracks on it.

6)STRIPPING:After the resist has performed its duty, it has to be completely

removed from the board. It is done by scrubbing or with the

help of a solvent or a commercially available stripping

solution.

7)DRILLING:Drilling of component mounting holes into the PCB is by far

most important mechanical machining operation in PCB

production processes. Holes are made by drilling wheneversuperior hole finish is required. There fore drilling is done by

all the professional grades PCB manufacturers and generally

in all small PCB production plants and laboratories. The

importance of hole drilling into PCB has further gone up with

its need for smaller hole diameter and higher package densitywhere hole punching is practically ruled out.

8)SURFACE CLEANING:After drilling the surface of the board is cleaned so that the

scraps may be removed which is settled on the board during

drilling? Surface cleaning has to be necessarily done.


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9)FINAL INSPECTION OF PCB:After complete fabrication the PCB inspected for any defect

such as short circuit or open circuit. This inspection is very

useful because if there is any fault in PCB, it is detected at the

earlier stage so that the defected PCB may not cause any

problem in the production of the equipment.


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SOLDERING TECHNIQUES

Knowing how to solder the components properly on the PCBis a prerequisite if we want to complete any electronics

project. Learning soldering techniques enables one to

construct, test and trouble shoot electronics circuits properly.

Soldering is the process of joining two metals by using solder

or we can state in this way that soldering is the alloying

process between two metals. Solder is a metal alloy, made by

combining tin and lead in different proportion. It is used to

join electrically conducting parts. When soldering the parts on

the PCB, the parts are first mechanically secured and then the

joint is heated with a soldering iron.

The solder is applied to the heated mating surface and is

allowed to melt and wet the surface. The soldering iron is

then removed from the joint. The finished solder joint forms

conducting electrical connection and a strong mechanical

joint between the component and the PCB.

The soldering process involves

1.Melting of the flux, which in turn removes the oxide filmon the metal to be soldered


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2.Melting of the solder which makes the lighter flux and theimpurities suspended in to the surface.

3.The solder partially dissolves some of the metal in theconnection

4.The solder cools and fuses with the metal.The soldering techniques includes understanding of

Soldering ToolsSoldering materialComponent preparationGood and bad soldering jointsDesoldering Techniques

SOLDERING TOOLS:To facilitate soldering work, various tools are necessary. The

most essential tools in the soldering practice are

1. SOLDERING IRON:Soldering iron is lightweight soldering tools, which generate

25 watt of heat. Which is best suited for light duty work as

soldering various electronics component on PCB. A soldering

iron supply sufficient heat to melt solder by heat transfer

when the iron tip is applied to a connection to be soldered.


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2. STRIPPERSStrippers are used to remove insulation from the wire as well

as for cutting the wire according to the requirement. These

strippers are so designed that they can accommodate various

sizes of wire normally used in electronics circuits. To prevent

damage to the wire by nicking, it should be ensured that the

specific wire size gauge could be set through the screw

provided on the one leg for the gauge setting.

3. BENDING TOOLSBending tools are pliers having smooth bending surfaces so

that they do not cause any damage to the component.

SOLDERING MATERIAL:1. SOLDER

The soldering material or solder usually employed for the

purpose of joining together two or more metals at

temperatures below their melting point is a fusible alloy

consisting essentially of Lead and Tin. Most common type of

solder used in electronics work is an alloy consisting of 60%

tin and 40% lead. The alloy is drawn into a hollow wire whose

center is filled with an organic paste called rosin. The resulting

product is called 60/ 40rosin- core solder. Its melting


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temperature is 190 C and solidifies as it cools. This alloy is

available in wire form in several gauges. Thinner gauges are

preferred over thicker ones. For general purpose soldering,

18-gauge wire solder is used. For close printed circuit work 22

or 20 gauge wire solder is used. Finer solder is easy to

position on the joint and requires less heat for the formation

of the joint.

2. FLUXTo aid the soldering process, another substance known as

flux is used. It is made of zinc chloride, hydrochloric acid,

and phosphoric acid and rosin.

Flux is needed to scrub away the microscopic film of oxides

on the surfaces of metals to be soldered and it forms a

protective film that prevents re-oxidation while the

connection is heated to the point at which the solder melts.

The solder used in most of the electronic work contains thisflux as a center core, which has a lower melting point than

solder itself. When the molten flux clears the metal, it

accomplishes two things

It allows the solder to wet the metal. It holds the oxides suspended in the solution.


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Metals, particularly copper when heated tend to oxidize and

prevent the alloying or good electrical bond between the

copper and the solder. Flux flowing over the leads, prevent

this oxidization process and as the solder flows the flux is

displaced allowing the solder to form an atomic bonding with

the items being soldered together. The molten solder can then

make contact with the cleaned and the solvent action of

solder on metal can take place. A good flux helps to keep the

surfaces clean.

COMPONENT PREPARATION:Before any component lead, wire or terminal is soldered in a

circuit; it is essential to clean it with isopropyl alcohol with thehelp of non- static Bristol brush for cleaning. The surface is

dried with paper or lint free muslin cloth.

The component fit properly in to the PCB, they must be

properly formed. Forming of the component has two main

functions

1. To secure the lead to the circuit.2. To provide proper stress relief. The relief is necessary to

prevent rupture of the component lead from the component

or in case of wire, to prevent a stress pull on the solder jointand rupture of the wire strands.


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The following steps are taken to properly bend the lead of the

components

1.The bend should be attempted not closer than 3-5mm fromthe component body.

2.The radius of the bend should be equal to twice thethickness of the lead wire.

3.Center the component between its solder connections.4.Bend the protruding lead 45-degree after insertion into the

circuit board & with the help of a bending tool.

5.Cut the lead so that no portion when bent exceeds theperimeter of the board with the help of a bending tool.

Forming is not necessary in the case of integrated circuits.

They are simply soldered to the board without cutting their

leads. Lead bending is the most important factor in forming.

A few sharp back and forth bends in a component lead can

easily because it to break close to the component

encapsulation may result in excessive stress at the lead

entrance, and cause cracks in the encapsulation. Such cracks

allow moisture to enter inside of the component and result in

gradual degradation of the component resulting in premature

failure.


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DESOLDERING TECHNIQUE:Desoldering means removal of solder from a previously

soldered joint. A very important consideration, which must be

kept in mind while desoldering, is that the heat required may

damage the base material and adjoining components.

Appropriate tolls will be used for desoldering. So that

minimum amount of heat is used during the desoldering

process. Do not use sharp metal object, such as a twist drill

for removing solder from component mounting holes. Sharp

objects may damage plated through conductor. Two

techniques are common in desoldering

1. Wicking2. Sniffing- Wicking:

A wicking solder remover may consist of a braided shield wirewith the core removed or it may be a piece of multistrand

wire. Wicks are available commercially, which are suitable for

desoldering work. The desoldering technique using wicking

process is as flows


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1. Place the wick on top of the solder joint to be solderedjoint to be desoldered.

2. Position the iron tip on top of the wick. The heat from theiron will melt the solder. The solder will readily flow into the

wick.

3. Cut off the wick containing the removed solder. Repeat theprocess until all the solder is removed from the joint.

SNIFFING:Vacuum type sniffer (solder sucker) uses a spring-loaded plunger.

It is commonly known as desolder pump. It uses a spring-loaded

mechanism. To use the device the spring is cocked and tip of the

vacuum pump is held against the solder joint. When the soldermelts, the trigger is operated which releases the spring, creating a

powerful vacuum action


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FUNCTION OF EACH COMPONENT

ELECTRONICS COMPONENTS

Any electronics project makes use of a variety of components.

Basically electronics circuit consists of electric circuits with

semiconductor devices and their associated R, C, L

components. The semiconductor component is used for

control purposes, amplification or rectification, where

necessary they are used as a visual display shows the results. A

through knowledge of components and their limitations is an

essential part of trouble free making of a project. A good

knowledge & understanding of special precautions in terms

handling, soldering and measurement of components would

reduce the chances of failure in making of electronics project.

In an electronics project, there are only five components three

Passive and two Active components are used as per following

diagram

ELECTRONICS COMPONENTS

PASSIVE COMPONENTS ACTIVE COMPONENTS

Resistors Capacitors Inductors Tubes Devices Semiconductors Devices


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PASSIVE COMPONENT

Components which are used in electronics circuit, But they arenot capable of amplifying or processing an electrical signal are

called passive components Resistor, capacitor and inductors are

called the passive components. But without the aid of these

components a transistors cannot be made to amplify the signals.

Let now discuss passive components in detail.

RESISTORS

It is defined as device or component, which offered resistance

to the flow of current, is called resistors. It is relates to

current as flows

Resistors = voltage / current

FUNCTION OF RESISTOR:

The function of resistors is to limit the amount of current or

to divide the voltage in a circuit.

The resistors are classified as given below

1. Fixed resistors2. Variable resistors


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FIXED RESISTORS:The value of resistors is fixed. The value of resistors cannot

be increased or decreased. It has only two ends. The most

commonly used types of resistors are

1. Carbon composition type.

2. Metal resistors.3. Wire wound resistors.

VARABLE RESISTANCE:The value of resistors is not fixed it can be changed as per the

requirement as in electronics circuits, sometimes it becomes


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necessary to adjust the value of current and voltages. The

variable resistors are usually called rheostats in other

applications. The variable resistors an be classified as follow

1. Linear

2. Non- linear

LINEAR VARIABLE RESISTORS:In this type of resistors the value of resistance from one end

to other end is equally divided. If we measured the value of

resistance at center of resistance then it will be equal to the

half of the total value of resistance. The moving contact will

determine whether the resistance in the circuit is minimum or

maximum value. The linear variable resistors are classified as


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1. Potentiometer2. PresetPOTENTIOMETERThe smaller variable resistors commonly used in electronics

circuits are called potentiometer usually abbreviated as pot. So

we can say Potentiometer is the second name of the variable

resistors.

Mostly there are three terminals to such a resistor, two are

fixed and one is connected to the variable contact

PRESETPreset is the variable resistors & they are used on PCB only.

Their value can be adjusted with the help of a small screwdriver.

It is commercially known as liner.


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NON LINEAR VARIABLE RESISTORS(Logarithmicvariation)

In this type of resistance the value of resistance from one end to

other end is not equally divided. If measured the value of

resistance at center of resistance then it will not equal to half the

total value of resistance. But it will be less or more than fixed

value of the resistance

IMPORTANT TERMS ABOUT RESISTANCE

TOLERANCE: -

This is the maximum value and minimum value of resistor is

in the percentage, which a resistor may undergo in value, due

to temperature, time, and moisture and heat dissipation.

STABILITY

Resistor is said to be stable, if after use under verified cycles

of heat and moisture its final value at room. Temperature is

almost near to its initial value at the same temperature.

RELIABILTY:

The resistor should not undergo any change in value except a

small percentage even after a long use.

POWER RATING:


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This is the in Watt that a resistor can dissipate at 25 C in still

air. The value of wattage indicates that resistor can pass more

current without any damage to itself.

Carbon resistors are available in 1/8 w, w, w, 1 w, and 2

w as per fig as shown

Wire wound resistors are available in very high wattage rating.

From fig it is clear that the size of resistor depends on the

wattage of the resistance. The size of resistors is less ifwattage is less and vice versa.


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Resistor values - the resistor colour code

Resistance is measured in ohms; the symbol for ohm is anomega .1 is quite small so resistor values are often given in k and M .1 k = 1000 1 M = 1000000 .

Resistor values are normally shown usingcoloured bands.

Each colour represents a number as shown inthe table.

Most resistors have 4 bands:

The first band gives the first digit. The second band gives the second digit. The third band indicates the number of

zeros. The fourth band is used to shows the

tolerance (precision) of the resistor, this

may be ignored for almost all circuits.

The ResistorColour Code

Colour Number

Black 0

Brown 1

Red 2

Orange 3

Yellow 4Green 5

Blue 6

Violet 7

Grey 8

White 9


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FUNCTION OF RESISTOR:

The function of resistors is to limit the amount of current orto divide the voltage in a circuit.

CAPACITOR

Capacitor or sometimes referred to as a Condenser is a

passive device, and one which stores energy in the form of an

electrostatic field. In its basic form a capacitor consists of two

parallel conductive plates that are not connected but are

electrically separated either by air or by an insulating material

called the Dielectric. When a voltage is applied to these

plates, a current flows charging up the plates with electrons

giving one plate a positive charge and the other plate an equal

and opposite negative charge. This flow of electrons to the

plates is known as the Charging Current and continues to

flow until the voltage across the plates (and hence the

capacitor) is equal to the applied voltage Vc. At this point thecapacitor is said to be fully charged and this is illustrated

below.

The parallel plate capacitor is the simplest form of capacitor

and its capacitance value is fixed by the equal area of the

plates and the distance or separation between them. Altering


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any two of these values alters the value of its capacitance and

this forms the basis of operation of the variable capacitors.

Also, because capacitors store the energy of the electrons in

the form of an electrical charge on the plates the larger the

plates and/or smaller their separation the greater will be the

charge that the capacitor holds for any given voltage across its

plates.

By applying a voltage to a capacitor and measuring the charge

on the plates, the ratio of the charge Q to the voltage V will

give the capacitance value of the capacitor and is therefore

given as: C = Q/V this equation can also be re-arranged to

give the more familiar formula for the quantity of charge on

the plates as: Q = C x V

The unit of capacitance is the Farad (abbreviated to F)

named after the British physicist Michael Faraday and is

defined as a capacitor has the capacitance of One Farad

when a charge ofOne Coulomb is stored on the plates by avoltage ofOne volt. Capacitance, C is always positive and has

no negative units. However, the Farad is a very large unit of

measurement to use on its own so sub-multiples of the Farad

is generally used such as micro-farads, nano-farads and pico-

farads, for example.


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Units of Capacitance

Microfarad (F) 1F = 1/1,000,000 = 0.000001 = 10-6 F Nanofarad (nF) 1nF = 1/1,000,000,000 = 0.000000001 =

10-9 F

Picofarad (pF) 1pF = 1/1,000,000,000,000 =0.000000000001 = 10-12 F

In electronics many types of capacitors are used but in this

project following type of capacitor are used

1.Ceramic Capacitor2.Electrolyte capacitor3.CERAMIC CAPACITOR:

These capacitor uses ceramic as dielectric material.

4.ELECTROLYTIC CAPACITORIn electrolytic capacitors, instead of using plates separated by a

dielectric, the capacitors have a metallic anode with oxide film

grown over it & this oxide layer acts as a dielectric. It is

surrounded by electrolyte.


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FUNCTION OF CAPACITOR

Capacitors store electric charge. They are used with resistors

in timing circuits because it takes time for a capacitor to fill

with charge. They are used to smoothvarying DC supplies by

acting as a reservoir of charge. They are also used in filter

circuits because capacitors easily pass AC (changing) signals

but they block DC (constant) signals.

DIODE

When a p type semiconductor is suitably joined to n-type

semiconductor, the contact surface is called pn junction.

A pn junction is known as a semi conductor or crystal diode

(so called because pn junction is grown out of a crystal)

The outstanding property of a crystal diode is to conduct

current in one direction only. A diode has two terminals.

When arrowhead of diode symbol is positive w.r.t bar of the

symbol, the diode is forward biased and if the arrowhead of

diode symbol is negative w.r.t bar, the diode is reversed

biased.
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P N

DIODE SYMBOL

DIODES PROPERTIES

Diode are the two terminal device like resistors and capacitorsIn diodes current is directly related to the voltage, as in the

resistors

In diodes the current is not linearly related to voltage, like inresistors.

APPLICATION OF THE DIODE

They are used in the power conversion. For example they areused to convert alternating current (AC) into direct current

(DC). Diodes are also used in voltage multiplier to convert AC

into very high DC voltages.

They are used in over-voltage protection for devices. Foeexample diodes are used in stepper motor and relay circuit to

de-energize coils rapidly without the damaging voltage spikes.

Many integrated circuits also incorporates diodes on the

connection pins

to prevent external voltages from damaging their sensitivetransistor


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They are used in the logic gate construction. This referred asdiode logic.

They are used in the temperature measuring.They are used in radio demodulation.

TRANSFORMER

Transformer is a static device i.e. one without any moving

part, which is used to step up or step down voltage. A

transformer works on the principle of mutual induction i.e.

whenever the amount of magnetic flux linked with a coil

changes, an e.m.f is induced in it. Generally transformers are

of two types.


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1. STEP DOWN TRANSFORMER

When the voltage on the secondary side is less than that of

the primary side then it is called step down transformer.

2. STEP UP TRANSFORMERWhen the voltage on the secondary side is more than that of

the primary side then it is called step up transformer.

The transformer used in the circuit serves two purposes

a)It steps down the A.C voltage.b)It provides electrical isolation from the main

supply hence reduces the risk of electrical shock.

BRIDGE RECTIFIER

A bridge rectifier is used for full wave rectification. It uses

four similar diodes. These are connected in the form of

bridge. It does not required use of center-tapped transformer.


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This reduces the size of the transformer for the same output

& hence there is saving in space and cost.

During positive half cycle of input voltage, diode D2 and D1

are forward biased. Current flows through D2 and D4. It

makes terminal A of RL positive with respect to terminal B

current flows through RL from A to B during negative supply

of input voltage, Diode D1 and D3 are forward biased.

Current flows through D1, RL and D3. Direction of current

through RL and output voltage Vo remains same. The output

wave shapes are as per diagram. The wave shape is same as

that of output of full wave rectifier using center tapped

transformer.


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In the bridge rectifier we use diode IN4007 whose current

carrying capacity is 1 ampere.

LDR (LIGHT DEPENDENT RESISTANCE)

The LDR is made of photosensitive material i.e. cadmium

solenoid, cadmium sulphide. The working of LDR is

dependent on the light. Thats why they are called light

dependent resistance. The resistance of the LDR depends

upon the amount of light falling on the LDR i.e. if more light

is falling LDR than its resistance is very low and vice versa.

They are used in the circuit of photography, streetlight and

hobby circuit. They are available in many size, value and

voltage. They are available from 13.5 mm to 5mm and value

from 0.5 k ohm to 60 k ohm and working voltage available

upto 300 volt.


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VOLTAGE REGULATOR (7805)

Voltage regulator IC unit contain the circuitry for referencesource, error amplifier, control device, and overload

protection all in single chip. A power supply can be built very

simply using transformer connected to ac supply to step the

voltage to a desired level, then rectifying with a half- or full-

wave circuit, filtering the voltage using a simple capacitorfilter, and finally regulating the DC voltage using an IC

voltage regulator. The voltage regulator can be classified as

Positive voltage regulator Negative voltage regulator

Voltage regulators that provide a positive fixed regulated

voltage over a range of load currents are schematically

represented in diagram. The fixed voltage regulator has an

unregulated voltage, Vin, applied to one terminal, delivers a

regulated output voltage, Vo, from a second terminal, with the

third terminal connected to the ground. An output input

voltage difference must be maintained for the IC to operate,

which means that the varying input voltage must be always be

kept large enough to maintain a voltage drop across the IC to

permit proper operation of the internal circuit. A group of


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fixed- positive voltage regulators is the series 78, which

provide fixed voltages from 5V to 24V.

CRYSTAL OSCILLATORSA crystal oscillator is an electronic circuit that uses the

mechanical resonance of a vibrating crystal of piezoelectric

material to create an electrical signal with a very precise

frequency. This frequency is commonly used to keep track of

time (as in quartz wristwatches), to provide a stable clock

signal for digital integrated circuits, and to stabilize

frequencies for radio transmitters and receivers. The most

common type of piezoelectric resonator used is the quartz

crystal, so oscillator circuits designed around them were called

"crystal oscillators".

Quartz crystals are manufactured for frequencies from a few

tens ofkilohertz to tens of megahertz. More than two billion

(2109) crystals are manufactured annually. Most are small

devices for consumer devices such as wristwatches, clocks,

radios, computers, and cell phones. Quartz crystals are also
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found inside test and measurement equipment, such as

counters, signal generators, and oscilloscopes.

A crystal oscillator is basically a tuned oscillator. It uses a

piezoelectric crystal as a resonant tank circuit. The crystal

(usually quartz) provides a high degree of frequency stability.

Therefore, the crystal oscillators are used whenever great

stability is required. In this project a crystal is used which has

the value 32.678 MHz.

CRYSTAL

SWITCH (PUSH-TO-ON)

A push-to-make switch returns to its normally open (off)

position when you release the button, this is shown by the

brackets around ON. This is the standard doorbell switch
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LIGHT EMITTING DIODES

The light emitting diode (LED) is, as name implies that will

give off visible light when it is energized. A light emitting

diode is basically a pn junction that emits light when forward

biased. Germanium and silicon diodes have less probabilities

of radiating light. By using materials such as gallium arsenide

phosphide (GaAsP) and gallium phosphide (GaP) we can

produce LEDs that radiate red, green or orange light. This

type of LED find application in instrumental displays, panel

indicators, digital watches, calculators, multimeters, intercoms,

telephone switch board etc. Infrared LED use gallium

arsenide (GaAs), and they emit invisible (infrared) radiation.

These LED find application in burglar- alarm systems and

other areas requiring invisible radiation.


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Anode Cathode

The correct polarity of an LED can usuallybe determined as follows:

sign: +

polarity: positive negative

terminal: anode cathode

wiring: red blackpinout: long short

interior: small large

shape: round flat

marking: none stripe

FUNCTION OF LED

LEDs emit light when an electric current passes through them

IC 358(OPERATIONAL AMPLIFIER)These devices consist of two independent high-gains,

frequency compensated operational amplifiers designed to

operate from a single supply over a wide range of voltage.

The low supply current drain is independent of the magnitude

of the supply voltage. Application include transducer

amplifier, dc amplification blocks, and all the conventional


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operational amplifier circuit that now can be implemented

more easily in single supply voltage systems. For example,

these devices can be operated directly from the standard 5-V

supply used in digital system and easily can be provide the

required interface electronics without additional +/- 5-V

supplies.

MICROCONTROLLER 16F877A

Special Microcontroller Features: 100,000 erase/write cycle Enhanced Flash program memorytypical

1,000,000 erase/write cycle Data EEPROM memory typical Data EEPROM Retention > 40 years Self-reprogrammable under software control In-Circuit Serial Programming (ICSP) via two pins Single-supply 5V In-Circuit Serial Programming Watchdog Timer (WDT) with its own on-chip RC oscillator forreliable operation

Programmable code protection Power saving Sleep mode Selectable oscillator options


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In-Circuit Debug (ICD) via two pinsCMOS Technology: Low-power, high-speed Flash/EEPROM technology Fully static design

Wide operating voltage range (2.0V to 5.5V) Commercial and Industrial temperature ranges Low-power consumption

PIN DIAGRAM


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BLOCK DIAGRAM OF MICROCONTROLLER


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MICROCONTROLLER FEATURE 16F877A

Operating Frequency DC20 MHzResets (and Delays) POR, BOR (PWRT, OST)

Flash Program Memory (14-bit words) 8KData Memory (bytes) 368EEPROM Data Memory (bytes) 256Interrupts 15I/O Ports Ports A, B, C, D, ETimers 3Capture/Compare/PWM modules 2Serial Communications MSSP, USART

Parallel Communications PSP10-bit Analog-to-Digital Module 8 input channelsAnalog Comparators 2Instruction Set 35 InstructionsPackages 40-pin PDIP

44-pin PLCC44-pin TQFP44-pin QFN


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PIN EXPLANATION


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LIQUID-CRSTAL DISPLAY (JHD 162-A)

The liquid crystal display (LCD) has the distinct advantage of

having a lower power requirement than the LED. It is

typically in the order of microwatts for the display, as

compared to same order of milliwatt of LED. It does,

however, require an external or internal light source, is limited

to a temperature range 0 to 60 centigrade. A liquid crystal is a

material that will flow like a liquid but whose molecular

structure has some properties normally associated with solids.

For the light scattering units are generally made of nematic

crystal structure as shown in fig.

The individual molecules have a rod like appearance as shown

in the fig.


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When no voltage applied across the LCD then incident light

will simply pass through and the liquid crystal structure will

appear clear. If voltage is applied across the conducting

surface as shown in fig the molecules arrangement is

disturbed, will the result that regions will be established with

the different indices of light refraction. The incident light will

be reflected in different directions at the interface between

regions of different indices of refraction with the result thatthe scattered light has a frosted glass appearance. The frosted

look occurs only where the conducting surface are opposite

each other and remaining area remain translucent. A digit on

an LCD display may have the segment appearance shown in

fig. The black area is actually a clear conducting surfaceconnected to the terminal below for external control. Two

similar masks are placed on opposite sides of a sealed thick

layer of liquid crystal material. If the number 2 were required,

the terminal 8, 7,6,3,4 and 5 would be energized.


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Pin connection of LCD

LM35 (Precision Centigrade Temperature Sensors)


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The LM35 series are precision integrated-circuit temperature

sensors, whose output voltage is linearly proportional to the

Celsius (Centigrade) temperature. The LM35 thus has an

advantage over linear temperature sensors calibrated in

Kelvin, as the user is not required to subtract a large constant

voltage from its output to obtain convenient Centigrade

scaling. The LM35 does not require any external calibration or

trimming to provide typical accuracies of 14C at room

temperature and 34C over a full 55 to +150C

temperature range. Low cost is assured by trimming and

calibration at the wafer level. The LM35s low output

impedance, linear output, and precise inherent calibration

make interfacing to readout or control circuitry especiallyeasy. It can be used with single power supplies, or with plus

and minus supplies. As it draws only 60 A from its supply, it

has very low self-heating, less than 0.1C in still air. The

LM35 is rated to operate over a 55 to +150C temperature

range, while theLM35C is rated for a 40 to +110C range (10 with

improved accuracy). The LM35 series is available packaged in

hermetic TO-46 transistor packages, while the LM35C,

LM35CA, and LM35D are also available in the plastic TO-92

transistor package. The LM35D is also available in an 8-lead


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surface mount small outline package and a plastic TO-220

package.

Features

Calibrated directly in Celsius (Centigrade) Linear + 10.0 mV/C scale factor 0.5C accuracy guarantee able (at +25C) Rated for full 55 to +150C range Suitable for remote applications Low cost due to wafer-level trimming Operates from 4 to 30 volts Less than 60 A current drain Low self-heating, 0.08C in still air Nonlinearity only 14C typical Low impedance output, 0.1 W for 1 mA load


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WORKING OF CIRCUIT

As per circuit diagram of project, it is build around thePIC16F877A microcontroller along with temperature and

heartbeat sensor. The block diagram of the circuit is given

below.

Heart beat sensor circuit

Heart rate can be measured by the ECG wave form or by the

blood flow into the figure (Pulse method). The pulse method

is simple and convenient. When blood flows during the

systolic stroke of the heart into the body parts, the finger gets

its blood via the radial artery on the arm. The blood flow intothe finger can be sensed photoelectrical.

LCD

DISPLAY

Microcontroller

PIC 16F877 A

POWER SUPPLY

HEART BEAT

SENSOR

TEMPERATURE

SENSOR


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To count the heart beats, here we use a small LED as a light

source on the one side of the figure (thumb) and observe the

change in the light intensity on the other side. The blood flow

causes variation in light intensity reaching the LDR, which

results in change in signal strength due to change in the

resistance of the LDR. The photocurrent is converted into

voltage and amplified by operational amplifier IC LM358. The

detected signal is given to the non inverting input pin-3 and

output is fed to another non-inverting input pin-5 for

squaring and amplification. The output pin 7 is connected to

the 15 of microcontroller which is port C pin. The

microcontroller is programmed to read this signal and

converted this signal into number of heart beat per minute.The heart beat per minute is display on the transmitter LCD

by microcontroller program.

Temperature sensor circuit

Person whose body temperature is to be measure, he shouldtouch the temperature sensor or hold it into the figures. The

temperature sensors give a voltage which is directly

proportional to the measured temperature. In the project

popular voltage output analog integrated circuit temperature

sensor LM35DZ is used to sense the temperature. This is a 3-pin analog output sensor which provides a linear output


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voltage of 10 mV/? C. The output of the temperature sensor

is given to microcontroller pin no 2, which is port A

input/output pin. The microcontroller programmed to read

the input of temperature sensor and read value of

temperature is display on the LCD by microcontroller

program.

Liquid crystal display

The LCD is used as output display device. It shows the value

read by the microcontroller from temperature sensor and

heart beat sensor. The LCD data inputs D0 to D7 to

microcontroller pin no 33 to 40 respectively (these are Port B

pins). The LCD pin 4 to 6 are connected to the

microcontroller pins 27 to 29 respectively (these are Port Dpins)

Power supply:-

A conventional circuit provides the 5volt regulated power

supply for the circuit. The A.C. mains stepped down by

transformer X1 to deliver a secondary output of 12 volt, 250

mA, which is rectified by full wave rectifier comprising of

diodes , filtered by capacitor C (1000 mfd) to eliminate ripples

and regulated by IC 7805 (IC1) to provide regulated 5V

power supply for the circuit.


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The working of project can be shown/understand by flow

chart given below


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Software used in the project


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PRECAUTIONS

1. Mount the components at the appropriate placesbefore soldering. Follow the circuit description and

components details, leads identification etc. Do not

start before making it confirm that all the components

are mounted at the right place.

2. Do not use a spread solder on the board, it may causeshort circuit.

3. Do not sit under the fan while soldering.4. Position the board so that gravity tends to keep the

solder where you want it.

5. Do not over heat the components at the board. Excessheat may damage the components or board.

6.The board should not vibrate while solderingotherwise you have a dry or cold joint

7. Do not put the Kit under or over voltage source. Besure about the voltage either D.C or A.C. while

operating the gadget.

8. Do not spare the bare ends of the components leadsotherwise it may short circuit with the other

components.


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BIBLIOGRAPHY

Books:

1.Principle of Electronics by V.K .MEHTA2.Basic Electronics by ERNARD GROB3.Electronics maker MAGAZINE

Websites:

1.www.howstuffworks.com2.www.wikipedia.com3.www.circuitlake.com4.www.8051projects.net5.www.squidoo.com
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Bimedical Temperature and Heart Beat Monitor

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