Fig. 2: Stretchable sensory array for high-quality dataset generation.

a, An exploded view of the 32-channel stretchable array, showing encapsulation, sensing electrodes, interconnections and substrates. b, Side view of the 32-channel device. c, Comparison of the device in its original and stretched states. d, The 32-channel device connected via a flexible flat connector (FFC) to a custom-made wireless module (Extended Data Fig. 1). e, Electrochemical impedance spectroscopy of hydrogels with (15 mg ml⁻¹ PEDOT:PSS with 150 mg ml⁻¹ AAm and 2.5 mg ml⁻¹ N,N’-methylenebisacrylamide) and without PEDOT:PSS. f, Impedance endurance plot under 100% strain. The inset image shows PEDOT interconnects under 0% and 100% strain. Z and Z₀ denote the impedance under strain and at the unstrained state, respectively. Scale bars, 20 mm. g, Welch’s power spectral density comparing PEDOT gel with Ag/AgCl electrodes of the same size. The inset illustrates the measurement setup using a dynamometer with electrodes attached to the forearm. h,i, SNR box plot of the device fabricated on a non-stretchable polyimide substrate (h) versus the device fabricated on a stretchable substrate (i), showing higher mean SNR across the 32 channels for the stretchable substrate. Data are presented as box plots showing the median (centre line), 25th–75th percentiles (box), and whiskers extending to the most extreme data points within 1.5× the interquartile range (IQR). The red dashed line indicates the mean value of the SNRs.