Noncontact Heartbeat and Respiration Monitoring Based on a Hollow Microstructured Self-Powered Pressure Sensor

Advances in mobile
networks and low-power electronics have driven smart mobile medical
devices at a tremendous pace, evoking increased interest in household
healthcare, especially for those with cardiovascular or respiratory
disease. Thus, flexible battery-free pressure sensors, with great
potential for monitoring respiration and heartbeat in a smart way,
are urgently demanded. However, traditional flexible battery-free
pressure sensors for subtle physiological signal detecting are mostly
tightly adhered onto the skin instead of working under the pressure
of body weight in a noncontact mode, as the low sensitivity in the
high-pressure region can hardly meet the demands. Moreover, a hollow
microstructure (HM) with higher deformation than solid microstructures
and great potential for improving the pressure sensitivity of self-powered
sensors has never been investigated. Here, for the first time, we
demonstrated a noncontact heartbeat and respiration monitoring system
based on a flexible HM-enhanced self-powered pressure sensor, which
possesses the advantages of low cost, a high dynamic-pressure sensitivity
of 18.98 V·kPa–1, and a wide working range
of 40 kPa simultaneously. Specific superiority of physiological detection
under a high pressure is also observed. Continuous reliable heartbeat
and respiration information is successfully detected in a noncontact
mode and transmitted to a mobile phone.