PIS: Wearable Pedal Iontronic Sensing for Arterial Pulses and Muscular Activities

We first introduce a foot-based wearable system named PIS which can both acquire body vital signals and track pedal muscular motions. Such system has been seamlessly integrated into a shoe format by constructing a highly sensitive and flexible pressure sensing array with the novel iontronic sensing principle, reaching a device sensitivity of up to 1 nF/mmHg with a detection range of 1 to 200 mmHg. As a result, we have successfully illustrated that PIS can capture high-definition peripheral arterial pulse waveforms, from which heart rates and respiratory patterns can be extracted within a medical-standard precision. Moreover, the high-spatial resolution of PIS allows alignment-free capture of pulse signals and provides a spatial reference to the pedal structures. It further enables tracking of individual pedal tendon activities, from which the majority of foot gestures can be distinguished.