HEART BEAT COUNTER

DIGITAL HEART-BEAT COUNTERDIGITAL HEART-BEAT COUNTER

RAKHI K CHANDRANRAKHI K CHANDRANRINIL M GRINIL M G

ROSHNI VERGHEESE ROSHNI VERGHEESE

SHAINY NARAYANAN SHAINY NARAYANAN SUCHITHRA K R SUCHITHRA K R

INTRODUCTIONINTRODUCTION

The heart beat rate is the number of times the persons heart The heart beat rate is the number of times the persons heart beat in one minute.beat in one minute.

Digital heart beat counter count the pulse continuously and Digital heart beat counter count the pulse continuously and automatically. automatically.

It have the following features:-It have the following features:-1.1. A piezoelectric accelerometer as sensor.A piezoelectric accelerometer as sensor.2.2. A blinking LED for visual indication of persons pulse.A blinking LED for visual indication of persons pulse.3.3. Counts are automatic and displayed on a 2 seven segment Counts are automatic and displayed on a 2 seven segment

display.display.4.4. Continuous monitoring can be done.Continuous monitoring can be done.5.5. Counting can be done from remote place.Counting can be done from remote place.6.6. Works off AC mains or batteries.Works off AC mains or batteries.

PRINCIPLEPRINCIPLE

A persons heart forces his blood to flow throw the A persons heart forces his blood to flow throw the arteries.arteries.

Arteries throb in synchronisation with the beating of Arteries throb in synchronisation with the beating of heart.heart.

Throbbing can be felt at wrist.Throbbing can be felt at wrist. Electronically this throbbing is sensed with an Electronically this throbbing is sensed with an

accelerometer, which convert it in to electrical signal.accelerometer, which convert it in to electrical signal. Counter section count the number of pulses for 10 Counter section count the number of pulses for 10

seconds and display it for 5 seconds. seconds and display it for 5 seconds.

•CARDIAC CYCLECARDIAC CYCLE

The function of heart is to maintain a constant The function of heart is to maintain a constant circulation of blood throughout the body.circulation of blood throughout the body.

This is acheived by rhythmic contraction of it’s This is acheived by rhythmic contraction of it’s muscle.muscle.

It is the sequence of events which occur in the It is the sequence of events which occur in the heart during a single beat.heart during a single beat.

The rate of heart is 72 beats per minute .The rate of heart is 72 beats per minute . Time taken for 1 beat is 0.8 seconds.Time taken for 1 beat is 0.8 seconds. It appears in two phasesIt appears in two phases

1. Systole - A period of contraction.1. Systole - A period of contraction.

2. Diastole – A period of relaxation. 2. Diastole – A period of relaxation.

•PULSEPULSE Pulse is the throbbing sensation felt over the walls of Pulse is the throbbing sensation felt over the walls of

arteries.arteries. Pulse rate is almost the same as heart rate .Pulse rate is almost the same as heart rate . The wrist is the common site where pulse is usually The wrist is the common site where pulse is usually

felt, which is referred as radial pulse.felt, which is referred as radial pulse. Bradycardia occurs when the pulse rate is below 60.Bradycardia occurs when the pulse rate is below 60. Tachycardia occurs when pulse rate is above 100.Tachycardia occurs when pulse rate is above 100. During sleep pulse rate is 40 BPM.During sleep pulse rate is 40 BPM.

BLOCK DIAGRAMBLOCK DIAGRAM

•PIEZO-ELECTRIC ACCELEROMETERPIEZO-ELECTRIC ACCELEROMETER

An accelerometer measures the instantaneousAn accelerometer measures the instantaneous acceleration acceleration of the object on which accelerometer is bounded. of the object on which accelerometer is bounded.

It transduce the acceleration which results from the It transduce the acceleration which results from the vibration to corresponding analog signal.vibration to corresponding analog signal.

Here we use piezoelectric type accelerometer is used.Here we use piezoelectric type accelerometer is used.

•PREAMPLIFIERPREAMPLIFIER

Here we useHere we use high input impedance pre-amplifier.high input impedance pre-amplifier. An instrumentation amplifier is used as a pre-amplifier.An instrumentation amplifier is used as a pre-amplifier. Three CA3140 op-amp IC’s unitedly act as an Three CA3140 op-amp IC’s unitedly act as an

instrumentation amplifier.instrumentation amplifier. Instrumentation amplifier is used because it greatly Instrumentation amplifier is used because it greatly

enhanced CMRR .enhanced CMRR .

•LOW PASS FILTERLOW PASS FILTER

The output signal from the instrumentation amplifier The output signal from the instrumentation amplifier gets adulterated with some harmonics of 50 Hz AC gets adulterated with some harmonics of 50 Hz AC power frequency, along with some other frequency power frequency, along with some other frequency components from surroundings.components from surroundings.

A sallen key low pass filter is used to reduce all these A sallen key low pass filter is used to reduce all these interferences.interferences.

•AMPLIFIER & PULSE INDICATORAMPLIFIER & PULSE INDICATOR

This amplifier section is used to drive the LED’s.This amplifier section is used to drive the LED’s. The LED’s blink in synchronization with heart beat The LED’s blink in synchronization with heart beat

pulse.pulse. One LED blink at the time of systole and another One LED blink at the time of systole and another

LED blink at the time of diastole.LED blink at the time of diastole.

•PULSE AMPLIFIER & MONOSTABLE PULSE AMPLIFIER & MONOSTABLE MULTIVIBRATORMULTIVIBRATOR

Pulse amplifier amplifies the LPF output.Pulse amplifier amplifies the LPF output. In two monostable multivibrators, one designed for 15 In two monostable multivibrators, one designed for 15

seconds and the other with time delay 10seconds. seconds and the other with time delay 10seconds. The monostable multivibrator helps to stay the display The monostable multivibrator helps to stay the display

for 5 seconds.for 5 seconds.

•INVERTER & 2-INPUT OR GATEINVERTER & 2-INPUT OR GATE

The inverter, inverts the output of monostable The inverter, inverts the output of monostable multivibrator and is used to enable the counter IC’s.multivibrator and is used to enable the counter IC’s.

The OR gate prevent the triggering of monostable The OR gate prevent the triggering of monostable multivibrator, while the display stays constant.multivibrator, while the display stays constant.

•DIGITAL COUNTER & SEVEN SEGMENT DIGITAL COUNTER & SEVEN SEGMENT DISPLAY DISPLAY

Digital counter count the number of pulses for Digital counter count the number of pulses for 10seconds.10seconds.

The counter IC here used is CD4033.The counter IC here used is CD4033. The counter gets incremented with each pulse.The counter gets incremented with each pulse. The seven segment display displays the number of The seven segment display displays the number of

pulses of 10 seconds.pulses of 10 seconds.

CIRCUIT DIAGRAMCIRCUIT DIAGRAM

The total circuit can be divided in to 4 The total circuit can be divided in to 4 sections as follows:-sections as follows:-

1.1. Pre-amplifierPre-amplifier

2.2. Low Pass FilterLow Pass Filter

3.3. Pulse MonitorPulse Monitor

4.4. Pulse Counter with digital readoutsPulse Counter with digital readouts

•PREAMPLIFIERPREAMPLIFIER

The heart of the circuit is a piezo-electric The heart of the circuit is a piezo-electric accelerometer .accelerometer .

The sensor outputs an electrical charge, directly The sensor outputs an electrical charge, directly proportional to magnitude of throbbing of artries.proportional to magnitude of throbbing of artries.

• This charge gives a voltage of order of few This charge gives a voltage of order of few millivolts across very high impedance of the millivolts across very high impedance of the piezo-electric crystal.piezo-electric crystal.

• Hence a high input impedance pre-amplifier Hence a high input impedance pre-amplifier is used.is used.

• The IC1,IC2,IC3 together act as pre-The IC1,IC2,IC3 together act as pre-amplifier.amplifier.

•LOW PASS FILTERLOW PASS FILTER

The amplified output voltage from IC3(CA3140) of The amplified output voltage from IC3(CA3140) of instrumentation amplifier is given to IC4 through resistor instrumentation amplifier is given to IC4 through resistor R10.R10.The op-amp IC4 along with resistors R10 and R12 and The op-amp IC4 along with resistors R10 and R12 and capacitors C4 and C5 forms unity gain Sallen key LPF.capacitors C4 and C5 forms unity gain Sallen key LPF.The upper cut frequency is approximately 1.5Hz.The upper cut frequency is approximately 1.5Hz.

•PULSE MONITORPULSE MONITOR

Apart ofApart of IC4 output is fed to a RC LPF comparing R14 and C7 IC4 output is fed to a RC LPF comparing R14 and C7 to pin 3 of op-amp IC5.to pin 3 of op-amp IC5.The RC filter enhance the steepness of previous filter The RC filter enhance the steepness of previous filter response.response.The additional stage amplification is for drive LED1 and LED2.The additional stage amplification is for drive LED1 and LED2.

The gain of this stage is approximately 22.The gain of this stage is approximately 22.

•PULSE COUNTER & DIGITAL READ OUTPULSE COUNTER & DIGITAL READ OUT

CMOS decade counters IC9(CD4033) and CMOS decade counters IC9(CD4033) and IC10(CD4033) in tandem form the two digit decimal IC10(CD4033) in tandem form the two digit decimal counter.counter.The counters, count the number of pulses from LPF The counters, count the number of pulses from LPF output.output.The output of first monostable multivibrator IC8,The output of first monostable multivibrator IC8,

( whose pulse width is 10 seconds) is given to clock ( whose pulse width is 10 seconds) is given to clock enable pin of IC10.enable pin of IC10.Pulse from the LPF, trigger both IC8 and IC9 Pulse from the LPF, trigger both IC8 and IC9 simultaneously.simultaneously.The output of IC8 remains high for 10 seconds and The output of IC8 remains high for 10 seconds and output ofoutput of IC9 for 15 seconds. IC9 for 15 seconds.

The counter counts for 10 seconds.The counter counts for 10 seconds.

After 10 seconds output of IC8 goes low, After 10 seconds output of IC8 goes low, hence output counter stops countings and hence output counter stops countings and will high for next 5 seconds.will high for next 5 seconds.

During this 5 seconds, OR gate prevent During this 5 seconds, OR gate prevent any other pulse on triggering IC8.any other pulse on triggering IC8.

Hence the counter output stay on last Hence the counter output stay on last count. count.

•POWER SUPPLYPOWER SUPPLY

Here we use a center tapped transformer (9-0-9,500mA).Here we use a center tapped transformer (9-0-9,500mA).The transformer is rectified by a full wave bridge rectifier The transformer is rectified by a full wave bridge rectifier comprising diodes D3 through D6.comprising diodes D3 through D6.The output of rectifier is filtered by using a capacitor filter .The output of rectifier is filtered by using a capacitor filter .This filtered output is given to fixed voltage regulators This filtered output is given to fixed voltage regulators 7805(+5V) and 7905(-5V).7805(+5V) and 7905(-5V).Regulators 7805,7905 provide +5V and -5V regulated Regulators 7805,7905 provide +5V and -5V regulated supply to circuit.supply to circuit.Capacitors C16 and C17 bypasses any ripple present in Capacitors C16 and C17 bypasses any ripple present in regulated supply. regulated supply.

•TELEPHONE PIEZO BUFFERTELEPHONE PIEZO BUFFER

•THE PIEZO-ELECTRIC THE PIEZO-ELECTRIC ACCELEROMETER SENSORACCELEROMETER SENSOR

•CONSTRUCTION OF THE SENSORCONSTRUCTION OF THE SENSOR

Instead of commercial accelerometer, self constructed Instead of commercial accelerometer, self constructed accelerometer is used.accelerometer is used.

It is constructed by using a ceramic piezo buzzer It is constructed by using a ceramic piezo buzzer element.element.

The diameter of the brass plate and silver layer of the The diameter of the brass plate and silver layer of the piezo buzzer plate is used in this project are around piezo buzzer plate is used in this project are around 27mm and 18mm respectively.27mm and 18mm respectively.

One of the two wire of 2 core shielded earphone cable One of the two wire of 2 core shielded earphone cable is connected to white silver layer sprayed over the is connected to white silver layer sprayed over the piezo element, and other wire to brass plate.piezo element, and other wire to brass plate.

Mount the mass centrally over the white silver layer.Mount the mass centrally over the white silver layer.

•ADVANTAGES ADVANTAGES

It count the pulses automatically and continuously. It count the pulses automatically and continuously.

Monitoring of the heart beat rate of a person from a Monitoring of the heart beat rate of a person from a remote place is also possible .remote place is also possible .

Besides its rate, some other qualities of the pulse reflect Besides its rate, some other qualities of the pulse reflect the state of the cardiovascular system. These are its the state of the cardiovascular system. These are its rhythm, fullness and shape of the pulse wave. The signal rhythm, fullness and shape of the pulse wave. The signal out from the LPF/amplifier IC5 maybe fed to a DAS out from the LPF/amplifier IC5 maybe fed to a DAS system for monitoring all these characteristic.system for monitoring all these characteristic.

Low cost.Low cost.

Simplicity of the circuit.Simplicity of the circuit.

DISADVANTAGESDISADVANTAGES

Due to the absence of desired value of resistors, Due to the absence of desired value of resistors, the time on which the counter, counts the pulse, the time on which the counter, counts the pulse, can’t be accurately set for 10 seconds.can’t be accurately set for 10 seconds.

Due to large number of discrete components, it Due to large number of discrete components, it is very difficult to troubleshoot in case of any is very difficult to troubleshoot in case of any failure.failure.

CONCLUSIONCONCLUSION

In this fast moving world even wasting In this fast moving world even wasting one minute is not imaginable . This is how we one minute is not imaginable . This is how we came to the idea of DIGITAL HEART BEAT came to the idea of DIGITAL HEART BEAT COUNTER which gives the opportunity to count COUNTER which gives the opportunity to count heart beat pulse automatically. As time moves heart beat pulse automatically. As time moves we can find digital heart beat counter in every we can find digital heart beat counter in every house, as heart diseases are common among house, as heart diseases are common among the people. And digital heart beat counter helps the people. And digital heart beat counter helps in detecting small variations in heart rate.in detecting small variations in heart rate.

THANK YOUTHANK YOU