One of two project reports. The other is designated
PART A: McMASTER (ON-CAMPUS) PROJECT / <p> It is well known that heart rate is an important physiological
parameter. In some cases, continuous monitoring of active subjects is
desireable. </p> <p> The report focuses on the feasibility of a miniaturized, portable
heart rate monitor. Good artifact rejections, low power consumption
small size and ease of use are of primary importance in such design.
In order to keep size as low as possible a single cell (1 .5 V) supply
voltage is used. </p> <p> A LED - phototransistor type of transducer was chosen for its
good artifact rejection and simplicity of application. The transducer
clips on the subject's earlobe. Light transmitted through the earlobe
is amplitude modulated by the heart (blood) pulses and detected by the
phototransistor thus providing electrical signal. </p> <p> In order to keep current drain low, the LED was powered by ~ 1% duty cycle pulses. The rest of the system was designed to comply with the requirements of the transducer. The detected train of pulses
were preamplified and the original modulating waveform (heart pulse)
reconstructed by a "sample and hold" circuit. The reconstructed signal
was amplified by a narrow-band-pass amplifier filter. </p> <p> An astable and two monostable multivibrators perform the necessary
timing. Two integrated circuits were also employed: a voltage
regulator, to provide stable reference voltages where needed and the
output amplifier filter, providing the bulk of the gain. </p> <p> A working prototype was built and suggests that a personalized
heart rate monitor is quite feasible. The whole circuit can be integrated,
with the exception of few capacitors and perhaps some trimming
potentiometers. </p> / Thesis / Master of Engineering (MEngr)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/20389 |
| Date | 01 1900 |
| Creators | Tzannidakis, Evangelos |
| Contributors | Barber, H. D., Engineering Physics |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
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