The Research Of Respiration Monitor Based On Humidity Sensor

With the continuous advancement of science and technology,people pay more and more attention to their own health,and respiratory monitoring equipment is gradually appearing in the public vision.Respiratory monitoring is a common method to prevent sudden onset of sleep apnea syndrome.When patients with sleep apnea syndrome experience apnea during sleep,respiratory monitoring equipment can detect this condition and issue an alert in the first time,thus earning valuable time for the treatment of sudden apnea.It is of great help to the health of patients.According to the current status of respiratory monitoring equipment at home and abroad,it is very meaningful to develop a respiratory monitoring device that is easy to carry and operate,low in cost,and high in reliability at home.This subject is to develop a respiratory monitor based on a humidity sensor,whose role is to monitor the breathing status of the monitored person during sleep,and to give an alarm immediately when the monitored person has apnea.The humidity value near the nose will change when breathing,and the humidity when exhaling is low,which is consistent with the indoor humidity.When exhaled,the humidity is very high,close to the full humidity(100%RH).Utilizing the humidity-sensitive characteristics of the humidity sensor to reflect changes in the humidity value of the monitored person’s breathing,the breathing condition of the monitored person can be determined.The hardware circuit of the system includes respiratory information acquisition device,microprocessor,conditioning circuit module,temperature compensation module,GSM communication module,display module,power circuit,storage module and alarm module.The principle of the respiratory monitor is through the impedance change of the resistive polymer humidity sensor in the respiratory information acquisition device under different humidity environments.It is transformed into a change in the frequency value by the conditioning circuit module.After the microprocessor detects the changed frequency value and calculates it through the temperature compensation module,the piecewise linear interpolation method is used to calculate the real-time humidity value according to the frequency and humidity relationship curve.The waveform displayed by the display module in real-time humidity value change is the real-time breathing waveform of the monitored person.When the set alarm condition is triggered,the GSM communication module sends a message to inform the caregiver.At the same time the buzzer of the alarm circuit beeps to inform the caregiver.The respiratory monitor has carried out many experiments.The display module can display the breathing waveform in real time,and the alarm module can issue an alarm when it is needed.Each module works well.The humidity sensor-based breathing monitor has high reliability and stability,which can better help people who need to monitor breathing,and has higher use value.