01-07-2014, 05:01 PM
Design of a Wireless Medical Monitoring System
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INTRODUCTION
In recent years, with the miniaturization of biomedical
sensors,the fast development and popularization of information
processing and wireless data transmission technology ,the
research of wireless Medical Monitoring System has became a
hot topic. By utilizing the wireless technique to transmit
information between medical sensor and monitoring control
center, the free space of patients is enlarged, and the efficiency
of the modern management of hospitals is improved. Besides,
the problem of the lack of unremitted real-time care for every
patient, which is caused by the shortage of health care
members, is also solved. Therefor, the portable wireless
medical monitoring products will become popular in the future
market[1].
HARDWARE DESIGN OF MEDICAL MONITORING
TERMINAL
The core of wireless medical monitoring system is the
design of wireless monitoring terminal, and the development of
system software. The monitoring terminal generally consists of
three modules: the sensor module, the control module, and the
wireless communication module. The sensor module is used
for acquiring medical information from the outside, and then
converts them to digital signals. The control module is often
compared to the brain of monitoring terminal, which is in
charge of coordinating the task of different modules,
controlling the sensors, processing data, and executing
communication protocols. The wireless communication
module mainly deals with the wireless transmission of
information.
Nowadays, there are various kinds of wireless
communication protocols[5]. But since the main task of a
monitoring terminal is to realize the transmission of signals---
such as heart rate, body temperature, and calling signals---the
data traffic is not heavy. Moreover, because the monitoring
terminal is worn on patients, which needs to be supplied by
The control chip uses Silicon LAB’s C8051F021.
C8051F021 is a model that belongs to C8051F series, a fully
integrated mixed-signal micro-controller. It has a high-speed
51 core, 64K bytes of FLASH memory, and hardware
implementation of the SPI Interface.
The wireless monitoring terminal block diagram is shown
in Fig.1, whose core is the C8051 MCU. It is connected with
CC2420 by SPI interface, and can read and writing inner
registers of CC2420, realizing the Wireless transceiver of
information. It can get information---such as psychological
parameters---from external sensors by ADC and DAC
modules. It is connected with the simulator and PC by JTAG
and UART series interface, therefore realizing the download
and on-line debug of programs. Through the external interrupt,
it could control the calling button to get the calling information
from patients, and process by interrupts.
CONCLUSION
Tests find that this system can successfully set up the
Zigbee star network. The monitoring terminal can precisely
check the heart rate and body temperature of patients, and send
them to coordinator and then surveillance center through
wireless network. The error of the monitored body temperature,
heart rate, and other information is very slight, which satisfies
practical usage, and meets the demand of the design. By
extending other sensor module, it could realize the monitoring
of more psychological parameters and reliable transmission.
Since this system only realized the detecting and
transmission of heart rate and body temperature, and the
detection accuracy is not enough. The next step focuses on how
to improve the detection accuracy, how to realize more reliable
transmission of data, and extend more sensor module, so as to
conduct further research on the monitoring of more
psychological parameters. At the same time, due to the
limitation of the master chip, the power dissipation of routers
and terminal device is not low enough. More work should be
done concerning this aspect to further reduce the power
dissipation and lower the cost.