A System for Monitoring Breathing Activity Using an Ultrasonic Radar Detection with Low Power Consumption

Abstract

Continuous monitoring of breathing activity plays a major role in detecting and classifying a breathing abnormality. This work aims to facilitate detection of abnormal breathing syndromes, including tachypnea, bradypnea, central apnea, and irregular breathing by tracking of thorax movement resulting from respiratory rhythms based on ultrasonic radar detection. This paper proposes a non-contact, non-invasive, low cost, low power consumption, portable, and precise system for simultaneous monitoring of normal and abnormal breathing activity in real-time using an ultrasonic PING sensor and microcontroller PIC18F452. Moreover, the obtained abnormal breathing syndrome is reported to the concerned physician’s mobile telephone through a global system for mobile communication (GSM) modem to handle the case depending on the patient’s emergency condition. In addition, the power consumption of the proposed monitoring system is reduced via a duty cycle using an energy-efficient sleep/wake scheme. Experiments were conducted on 12 participants without any physical contact at different distances of 0.5, 1, 2, and 3 m and the breathing rates measured with the proposed system were then compared with those measured by a piezo respiratory belt transducer. The experimental results illustrate the feasibility of the proposed system to extract breathing rate and detect the related abnormal breathing syndromes with a high degree of agreement, strong correlation coefficient, and low error ratio. The results also showed that the total current consumption of the proposed monitoring system based on the sleep/wake scheme was 6.936 mA compared to 321.75 mA when the traditional operation was used instead. Consequently, this led to a 97.8% of power savings and extended the battery life time from 8 h to approximately 370 h. The proposed monitoring system could be used in both clinical and home settings.

A Review of the State of the Art in Non-Contact Sensing for COVID-19

“…Respiratory movement can then take place between the transmitter and receiver and creates a Doppler affect. This can then be used to create a contactless breathing monitor [ 62 , 63 , 64 ]. Ultrasound technology can be performed using smartphones for the signal and processing of ultrasound images in a portable setting [ 65 ].…”

Contact-Free Biosignal Acquisition via Capacitive and Ultrasonic Sensors

“…To avoid influences from the filters' group delays, zero-phase filters are chosen. As shown in several other publications, the ultrasonic signal provides very similar data regarding heart activities [9], [10], [44]. However, even though the proposed implementation of this ultrasonic sensor provides a very high resolution, this particular measurement result was hard to achieve and required several attempts.…”

“…Since the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO) classifies radio frequency electromagnetic fields as possibly carcinogenic to humans, long-term UWB or other radio frequency-based approaches might lead to a low patient acceptance [19], [20]. Regarding the experiments in recent publications, ultrasound-based distance measurements for biosignal acquisitions lead to promising results [9], [10], [21], [22]. However, the number of publications is low and the performed studies do not cover large groups of subjects.…”

Contactless Human Activity Analysis: An Overview of Different Modalities

“…Hence, in contrast to the RF-based ToF, the processing unit associated with the receiver in sound-based ToF, computes the ToF directly by comparing the transmitted and received signal. This process is based on the following equation [43]:…”