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Abstract:Generally heart rate monitoring is the basic phenomena measured for monitoring health status of a patient. This parameter measurements should be safe and without any risk. In this case, fiber optic sensors are used for monitoring heart rate. Generally cables are preferred than the electrodes because the information can be transmitted in larger bandwidth. Only contact with patient is optical fiber cable hence we can assure that patient is isolated from electrical hazards.
INTRODUCTION
The normal heart beat for adults is 60-100 beats per minute while awake and 40-60 beats per minute while sleeping. By measuring the heart rate, one can know the physiological function of the human body.The most common techniques used to obtain heartbeat signals are photo-plethysmography, impedanciometry, piezoelectric sensors.The optic cables are preferred over the electrodes because it eliminates the electric sparks and also transfers information with greater bandwidth. Medical fields have developed new sensors to perform vital signal monitoring in hazardous environments. Fiber optic sensors can solve problems involving high temperature, electromagnetic interference, and humidity environments and provides electrical safety. Commonly used sensors for measuring heart beat is SEN11574. The main advantage of this sensor is side effect free sensor. Optic fiber transmits information through light which conserves electricity. One of the major parts of the human body which gets easily affected is heart. The commonly occurring disease is hypertension and hypotension. When a person’s heart beats more than 80 beats per minute it is termed as Hypertension. When a person’s heart beats less than 20 beats per minute it is termed as Hypotension. SENSORS
Platinum resistance thermometers (PRTs)
It offers excellent accuracy over a wide temperature range (from –200 to +850 °C). Standard sensors are are available from many manufacturers with various accuracy specifications and numerous packaging options to suit most applications. Unlike thermocouples, it is not necessary to use special cables to connect to the sensor.
The principle of operation is to measure the resistance of a platinum element. The most common type (PT100) has a resistance of 100 ohms at 0 °C and 138.4 ohms at 100 °C. There are also PT1000 sensors that have a resistance of 1000 ohms at 0 °C.
The relationship between temperature and resistance is approximately linear over a small temperature range: for example, if you assume that it is linear over the 0 to 100 °C range, the error at 50 °C is 0.4 °C. For precision measurement, it is necessary to linearise the resistance to give an accurate temperature. The most recent definition of the relationship between resistance and temperature is International Temperature Standard 90 (ITS-90).For a PT100 sensor, a 1 °C temperature change will cause a 0.384 ohm change in resistance, so even a small error in measurement of the resistance (for example, the resistance of the wires leading to the sensor) can cause a large error in the measurement of the temperature. For precision work, sensors have four wires- two to carry the sense current, and two to measure the voltage across the sensor element. It is also possible to obtain three-wire sensors, although these operate on the (not necessarily valid) assumption that the resistance of each of the three wires is the same.
NON INVASIVE HEART RATE SENSOR
A type of wearable, non-invasive electronic device that can monitor vital signs such as heart rate and respiration at the same time it records a person's activity level, opening new opportunities for biomedical research, diagnostics and patient care. The device is just two inches wide, comfortable, does not have to be in direct contact with the skin and can operate for a week without needing to be recharged. Data can then be downloaded and assessed for whatever medical or research need is being addressed.
Heart rate monitors generally come in two types either a wireless chest strap that sends data to a monitor worn on the wrist, or pulse monitor worn on the wrist that requires you to put your finger on a certain spot to take your pulse.
As the heart beats, an electrical signal is transmitted through the heart muscle in order for it to contract. This electrical activity can be detected through the skin. The transmitter part of the heart rate monitor is placed on the skin around the area that the heart is beating, and picks up this signal. The transmitter then sends an electromagnetic signal containing heart rate data to the wrist receiver which displays the heart rate.
Simple heart rate monitors may only show you the heart rate at a given time. More elaborate monitors are available that not only shows the heart rate, but can be set to record time, calculate average and maximum heart rate for an exercise period, and can sound an alarm when a runner reaches or exceeds a pre-determined target heart-rate zone.
PROPOSED SYSTEM
A) METHODOLOGY:
The heart rate is measured using the SEN11574 sensor. This sensor is placed in the chest as well as in the fore finger. The optic cable used as the medium of information transmission. This information signal is transmitted to signal condition module which includes the data acquisition technique. The embedded system block includes microprocessor, peripheral device, and direct industrial functions. The signal containing heart rate information is sent to personal computer. The detailed information is stored in pc as well as it is transferred to doctors website. This information transmission is done via IOT. On continues process of monitoring this information will be much useful
MONITORING:
The end of the fiber should be polished to avoid abstractions during transmission and to get a better quality signal.For heart rate: The fiber end should be placed at right hand fore finger and other receiver end should be placed back side of the fore finger. The light that is transmitted will penetrate through the tissues and blood vessels will contain the information about the heart rate.The application of sensors allows a large number of developments in monitoring physiological signal even during harsh environments. Some examples of sensors based monitoring applications are MRI, aquatic rehabilitation. For the best comfort of patient and electrical isolation, the fiber cable can be preferred. The cable that is to be used should be properly tested and used.
The heart rate is measure in terms of plethysmography signal. The above figure explainsabout the basic flow of information about the heart rate pulse.
FEATURE WORK
In future along with measurement of heart rate, respiration measurement,dehydration can also be done. In addition to this fetal heart rate measurement can be done with proper use of sensors.
CONCLUSION
The quality of imaging will not be affected by using the sensors as in the case of MRI measurements. The information is transmitted using optic cable hence there are minimal possibilities of losing the signal due to electromagnetic wave interference. Using IOT the patient health can be monitored wherever possible. These data can be access instantly. The all monitored information’s are stored in personal computer as well as in IOT. The current techniques requires patient not to move his or her hands, foot and head during measurements which could be added to the output signal.