Fig. 5: An LPTHE patch for continuous and multi-parameter health monitoring.

a Exploded view of the LPTHE patch. b Functional block diagram of the LPTHE patch. LDO, low dropout regulator; BLE, Bluetooth low energy; ASIC, application-specific integrated circuit; UART, universal asynchronous receiver transmitter; ADC, analog-to-digital converter; SPI, Serial peripheral interface; I²C: inter-integrated circuit bus; In-amp, instrumentation amplifier. c Photo of the LPTHE patch with its FPCB counterpart in the inset. d Photos of the LPTHE patch bent along the surface of a cylinder with a 27 mm diameter. e Photos of the LPTHE patch showing its (i) front side, (ii) back side without encapsulation and (iii) back side with encapsulation. f Photos of the LPTHE patch on the left chest of a volunteer. g Photos of human skin after exercising with the LPTHE patch and the FPCB patch, respectively. h, i Photos of the LPTHE patch under (h) ~40% strain and (i) twisting. j Multiple signals measured using the LPTHE patch during cyclic twisting. ACC: acceleration; S-ECG: simulated ECG. k Schematic of the LPTHE patch worn on a volunteer for real-time monitoring during exercise. l, m Comparison between the LPTHE patch and the FPCB patch in measuring (l) ECG signals and (m) temperature/humidity signals.