Respirometer by a piezo device and its application to triage

In this paper, we present a novel respirometer using the effect of piezo devices and show its application to triage. We found that blowing on the piezo device generated several 100 mV voltage and also synchronizes with the respiration. Our detailed investigations of the phenomena showed that it was caused by the pyroelectric effect. In general, the piezo device when used as a sensing device generates output voltage in a batteryless manner and also functions as a buzzer, which can lead to a compact, simple and low-power respirometer. Here, the piezo device was used as a base of respirometer and not only as a respirometer, but also as an alarm sound generator. Thus, the proposed respirometer was realized only by one piezo device and a low-powered microprocessor driven by a small battery. We applied the respirometer to triage and realized a triage sensing system. In the system, we employed the triage priority determination procedure defined as an international standard. The triage sensing system set in a mask detects respiration and displays its condition by turning an LED on and off, synchronizing the respiration and also generating the alarm sound when the respiration falls into the pre-specified ill conditions.