Novel MEMS Respiratory Flow Sensor
Respiration activity is commonly monitored clinically to prevent sudden infant death
syndrome or to record a patient’s physiological status for sleep studies and sports training].
Various sensors and sensing methods have been developed to measure respiratory rate and/or
lung capacity, including the monitoring or measurement of transthoracic impedance, blood
O2/CO2 concentration, and breathing airflow among them, breathing airflow measurement is the
most direct method, since it measures airflow directly, rather than estimating it by measuring
another parameter.
Breathing airflow is typically detected by sensing pressure or temperature, and the
adopted sensors may be resistive, thermoelectric, pyroelectrical, or piezoelectric. In the present
work, a resistive, CMOS-process-compatible flow sensor is proposed.
Existing System:
Generally the information on respiration should be monitored personally by an expert.
The respiratory flow is measured by sensors or any other devices and is noted periodically in
patients’ medical file manually. The values are analyzed for abnormality by a medical expert and
treatment is given according to that.
Proposed System:
In this project, MEMS sensor is used for monitoring the respiration flow rate of the
patient. This resistive flow sensor was manufactured by the TSMC 0.35 m CMOS/MEMS
mixed-signal 2P4M polycide process. The sensor was demonstrated to be sensitive enough to
detect the respiratory flow rate, and the relationship between flow rate and sensed voltage is
quite linear. If one can integrate the sensor with its sensing circuit into a single chip, the cost of a
pneumotach system can be greatly reduced. Moreover, the proposed sensor is useful in both
invasive and noninvasive applications.
Block Diagram:
Hardware Requirements:
8051 MCU.
MEMS sensor.
ADC 0808.
GSM Module.
Software Requirements:
Keil C compiler.
Embedded C.
8051
Micro
Controller
Power supply
Supply
MEMS
Sensor
MAX
232
ADC
0808
Advantages
Since the measurements are taken automatically, there is low possibility for errors to
occur which could avoid fatal.
Erroneous values may not be noted.
Database maintenance may be managed easily. In this case the patient can move onto his
work.