Piezoelectric and electromagnetic respiratory effort energy harvesters

Sensing Systems for Respiration Monitoring: A Technical Systematic Review

Respiratory monitoring is essential in sleep studies, sport training, patient monitoring, or health at work, among other applications. This paper presents a comprehensive systematic review of respiration sensing systems. After several systematic searches in scientific repositories, the 198 most relevant papers in this field were analyzed in detail. Different items were examined: sensing technique and sensor, respiration parameter, sensor location and size, general system setup, communication protocol, processing station, energy autonomy and power consumption, sensor validation, processing algorithm, performance evaluation, and analysis software. As a result, several trends and the remaining research challenges of respiration sensors were identified. Long-term evaluations and usability tests should be performed. Researchers designed custom experiments to validate the sensing systems, making it difficult to compare results. Therefore, another challenge is to have a common validation framework to fairly compare sensor performance. The implementation of energy-saving strategies, the incorporation of energy harvesting techniques, the calculation of volume parameters of breathing, or the effective integration of respiration sensors into clothing are other remaining research efforts. Addressing these and other challenges outlined in the paper is a required step to obtain a feasible, robust, affordable, and unobtrusive respiration sensing system.

Electromagnetic respiratory effort harvester: human testing and metabolic cost analysis

Remote health monitoring is increasingly recognized as a valuable tool in chronic disease management. Continuous respiratory monitoring could be a powerful tool in managing chronic diseases, however it is infrequently performed because of obtrusiveness and inconvenience of the existing methods. The movements of the chest wall and abdominal area during normal breathing can be monitored and harvested to enable self-powered wearable biosensors for continuous remote monitoring. This paper presents human testing results of a light-weight (30 g), wearable respiratory effort energy harvesting sensor. The harvester output voltage, power, and its metabolic burden, are measured on twenty subjects in two resting and exercise conditions each lasting 5 min. The system includes two off-the-shelf miniature electromagnetic generators harvesting and sensing thoracic and abdominal movements. Modules can be placed in series to increase the output voltage for rectification purposes. Electromagnetic respiratory effort harvester/sensor system can produce up to 1.4 V, 6.44 mW, and harvests 30.4 mJ during a 5-min exercise stage. A statistical paired t-test analysis of the calculated EE confirmed there is no significant change ( P > 0.05 ) in the metabolic rate of subjects wearing the electromagnetic harvester and biosensor.