A Planar Respiration Sensor Based on a Capaciflector Structure

Respiratory diseases, such as asthma and chronic obstructive pulmonary disease (COPD), affect more than 300 million people worldwide. Devices such as the pneumotachograph are currently used within a clinical environment for measuring the inhalation, expiration, and respiration cycle but are physically large and not suitable for home use by patients. A small, lightweight respiration sensor for use in the home environment allows patients to monitor respiratory rate in a simple manner. The capaciflector was originally developed by NASA as a capacitive proximity sensor for collision detection in robots. We have found that the device can also be used to detect breathing patterns in humans by attaching it to the chest. In this article, we discuss the simulation, construction, and testing of a capaciflector for use as a respiration sensor and describe how it can be interfaced to a microcontroller in order to allow us wireless data transmission over a Wi-Fi signal.