The Non-contact Respiration Detection And Bluetooth Communication Based On ARM

Breath test during a sleep has positive meaning in preventing sleep apnea syndromeand monitoring the vital signs in human body sleeping. Contact detection methods have aconsiderable restrictive on human body, as human sleep can be affected by a long breathtest. Focusing on the above-mentioned problem, a non-contact detection method was putforward in this paper based on capacitance frequency modulation, which could avoidlimits on human body due to the electrode slice or the sensor and improved comfort duringthe detection process, while the accuracy of the measurement results was ensured. Signalacquisition and process based on embedded systems can reduce volume and cost of thedata acquisition unit. Wireless transmission of breath signal using bluetooth technologycan extend the external display functions of the local acquisition system. A more detaileddescription of the research is presented as follows:Transforming the change of thorax to change in capacitance and Modulatingfrequency for the oscillating circuit by using detection electrode, according to the changeof thorax during the process of body respiration, thus realized the non-touchingmeasurement of breath signal. Demodulating the breath signal from frequency-modulatedsignals then amplified and filtered it with the help of frequency discriminating circuit andfilter circuit, which realized signal acquisition and process.ARM microprocessors and Windows CE operating system were used in signalacquisition and process. Breath signal was sent to the external display device in real timeby bluetooth. android-based application development was researched, aiming atcontrolling the android device to receive and display the breath signal by means ofprogram, thus monitored the breath signal in real time.Human posture during sleep is not fixed, which may lead to the distortion andmissing of detection signal. By means of increasing the number of detection electrodes,and multi-point detection of the body breath signal, the one-sidedness and locality due topicking up signals only by single detection electrode were remedied. By using componentanalysis algorithm, synthesized the partly incomplete breath signal provided by detection electrodes distributed across several locations so as to eliminate the possible redundancyand disdurb between the multi-dimensional detection signals. Plus complementary andreducing uncertainty, thus improved the signal to noise ratio of breath signal and thecollection of breath signal, then the non-contact measurement of breath signal wasrealized.