Extended Data Fig. 4: Electrical timer for time-sequenced iontophoretic stimulation.
a, An optical photograph of the implemented electrical circuit including electrical timer, iontophoresis stimulation and power management integrated circuit (PMIC). Scale bar, 5mm. b, A close-up photograph of the implemented electrical timer circuit for time-sequenced iontophoretic stimulation, fabricated on a flexible PCB. Scale bar, 5 mm. c, An optical photograph of the wireless charging module. Scale bar, 5 mm. d, Schematic of the electrical timer circuit. e, Fully implemented circuit for time-sequenced iontophoretic stimulation. f, Power management integrated circuit and operating principle for wireless charging. g, Experiental results showing interval time as a function of long timer resistance. n = 3. h, Iontophoresis stimulation time as a function of short timer resistance. n = 3. i, Experimental results showing the cycle variation in sweat stimulation time and time interval between stimulation. n = 3. Data are presented as mean values ± SD (n = 3 technical replicates).
