Zhang, HuiyangKalra, AnubhaLowe, AndrewYu, YangAnand, Gautam2026-05-202026-05-202023-02-01Sensors, ISSN: 1424-8220 (Print); 1424-8220 (Online), MDPI AG, 23(3), 1571-. doi: 10.3390/s230315711424-82201424-8220http://hdl.handle.net/10292/21148<jats:p>Recent advancement in wearable and robot-assisted healthcare technology gives rise to the demand for smart interfaces that allow more efficient human-machine interaction. In this paper, a hydrogel-based soft sensor for subtle touch detection is proposed. Adopting the working principle of a biomedical imaging technology known as electrical impedance tomography (EIT), the sensor produces images that display the electrical conductivity distribution of its sensitive region to enable touch detection. The sensor was made from a natural gelatin hydrogel whose electrical conductivity is considerably less than that of human skin. The low conductivity of the sensor enabled a touch-detection mechanism based on a novel short-circuiting approach, which resulted in the reconstructed images being predominantly affected by the electrical contact between the sensor and fingertips, rather than the conventionally used piezoresistive response of the sensing material. The experimental results indicated that the proposed sensor was promising for detecting subtle contacts without the necessity of exerting a noticeable force on the sensor.</jats:p>© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).https://creativecommons.org/licenses/by/4.0/electronic skinhuman-machine interfacehydrogel sensorimpedance tomographysoft interfacesoft roboticssoft sensortomographic imagingtouch sensor40 Engineering4003 Biomedical Engineering46 Information and Computing Sciences4009 Electronics, Sensors and Digital Hardware4605 Data Management and Data Science4016 Materials EngineeringBiomedical ImagingBioengineering4.1 Discovery and preclinical testing of markers and technologies4.2 Evaluation of markers and technologies0301 Analytical Chemistry0502 Environmental Science and Management0602 Ecology0805 Distributed Computing0906 Electrical and Electronic EngineeringAnalytical Chemistry3103 Ecology4008 Electrical engineering4104 Environmental management4606 Distributed computing and systems softwareHumansTouchElectric ImpedanceHydrogelsTomography, X-Ray ComputedWearable Electronic DevicesHumansHydrogelsTomography, X-Ray ComputedTouchElectric ImpedanceWearable Electronic DevicesHumansTouchElectric ImpedanceHydrogelsTomography, X-Ray ComputedWearable Electronic DevicesJournal ArticleOpenAccess10.3390/s23031571