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The meter
is intended for systolic, diastolic pressure, and pulse rate measurement
in medical institutions and at home. It does not require any special
skills for the user and may be used for self-measuring. Ten recent
measurement results are stored in internal archive. The device
can work under PC control transferring internal tables and signal
samples for analysis and algorithm improvements.
Between measurements
the device stays in Low Power Mode 3 (consumed current is less
than 10 micro amps). When the I/O button is pressed the MCU wakes
up and prepares for measurement. It displays the LCD test and
then maximum pressure, which should be 30-40 mm hg higher than
expected systolic pressure. Then the meter goes to "ready to measure"
mode, indicated by a buzzer.
The cuff must
be placed around the user's hand and connected to the meter via
the attached air tube. During measurement the LCD displays current
pressure value. The air compressor inflates the cuff up to specified
maximum pressure and stops. Air steadily goes out through the
vent hole. The MCU samples the pressure sensor signal and extracts
instantaneous pressure changes caused by blood pulses. Each detected
pulsation is indicated by heart icon blinking and by buzzer sound.
Simultaneously the pulse rate is measured. At pressures below
diastolic, the measurement stops and pulsation parameters are
used to calculate systolic and diastolic pressures. If maximum
pressure appears insufficient it's automatically incremented by
40 mm hg and the measurement cycle is repeated.
The user can
view archive data by pressing and holding the I/O button. The
Start button scrolls through archive. Pressing and holding the
I/O button once more cancels archive reading. The device is turned
off by shortly pressing the I/O button or when no buttons are
pressed during 3 minutes.
Block
Diagram
A. Britov,
V. Zakharchenko, V. Lomakovsky, A. Makeenok, & S. Khlebnikov
Kiev, Ukraine
dsplab@cad.ntu-kpi.kiev.ua
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