Fig. 5: The PFM based liquid sensor for continuous cardiac monitoring.
From: A reconfigurable and conformal liquid sensor for ambulatory cardiac monitoring
a 3D scanning technique to capture tomographic images of the skin surface. Scale bar, 8 mm. b Enlarged view of the skin surface. Scale bar, 3 mm. c Image of the liquid cardiac sensor on the wrist. Scale bar, 8 mm. d Circuit diagram of liquid cardiac sensor, including microcontroller (MCU), encapsulation, battery, and wireless module. e Using only the soft coil for pulse wave monitoring. f Characteristics of pulse wave from the liquid sensor. g Testing of the liquid sensor with different PFM volumes of 20, 30, and 50 µl. h Liquid sensors measured simultaneously at two sites: one on the forehead and one on the wrist. i Magnetic field of the PFM was measured when it was slightly spread. j Liquid sensor tested before spread and after spread. k Comparison between the liquid sensor and a gold-standard photoplethysmography (PPG) sensor. l Comparison of our device and PPG sensors with respect to their SNR. Source data are provided as a Source Data file.
