Smart Skin Technology
Developed originally at the lab and liscenced in 2019 to X-trodes, the Smart Skin technology is transforming non-invasive electrophysiology: From conventional bulky, wired and gelled systems into easy to use wearable systems
Evaluation Kit
X-trodes develops user-friendly and small form factor hardware, wearable electrodes that can sense high-quality electrophysiological signals, and specialized analytical tools for analyzing electrophysiological data. The X-trodes evaluation kit allows researchers to explore a wide range of applications and is currently used by researchers and HMI companies worldwide. The X-trdoes evaluation kit offers great value in simplicity and data quality for a wide range of applications. Applications span from finger gesture recognition for human-computer interaction and prosthetic control to sleep research. Additional use cases include voiceless speech decoding, gait analysis for movement disorders, sports medicine performance tracking, psychological research involving stress and emotional response, facial expression monitoring in HCI and affective computing, and rehabilitation, where muscle activity mapping can inform therapy and recovery strategies. The system’s flexibility, comfort, and reliability make it an ideal tool for researchers in these fields.
System Overview
The x-trodes evaluation kit is a powerful research and development platform that allows quick and easy electrophysiological data collection and analysis.
The Data Acquisition Unit (DAU)
The DAU saves the data to a micro-SD card and also transmits a continuous Bluetooth signal to an Android tablet application. The DAU supported up to 16 unipolar channels (2 μV noise rms, 0.5–700 Hz) with a sampling rate of 4000 S/s, 16-bit resolution, an input range of 12.5 mV, and an input impedance of 10 MΩ. A 620 mAh battery supports the DAU operation for a duration of up to 16 h.
The Electrodes
The disposable electrodes consist of 16 electrodes (channels). The X-trodes electrodes are printed onto a polyurethane layer. The electrode array is attached to the skin first by peeling off an adhesive film and then applying the array to the skin while ensuring precise location. Arrays are designed to accommodate specific applications, and arrows indicate the specific landmarks. An outer protective film is peeled away one by one to fully attach the mask. The mask’s design offers considerable flexibility, allowing for adjustable positioning of the combined electrodes.
Noise
Noise originates from the data acquisition electronics, thermal noise associated with the skin-electrode impedance, and baseline physiology. Owing to frequency dependence of the impedance, large variability in contact impedance values across different body regions, and large differences in baseline physiological conditions, noise has to be carefully reported. Below is a summary of some main recorded values. See more here.
Face - Physiological Noise < 7 μV for the 0.3–35 Hz
Face - Thermal noise face <0.6 μV for the 0.3–35 Hz
Face - Physiological Noise < 5 μV for the 30-350 Hz
Face - Thermal noise face <1 μV for the 30-350 Hz
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Arm - Thermal noise/Physiological Noise < 8 μV for the 30-350 Hz
Compatibility with additional recording devices
Although the system was designed to work as a stand-alone medical-grade system, several hacks were developed in the lab to support its use in experimental setups.
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PsychoPy can be used to send annotations to the Android application
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Data can be streamed to a PC, pre-processed, and visualised with a Python code
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Data can be streamed to LSL and collected synchronously with multiple LSL-supported devices, such as microphones, Mobile Phone IMU, etc.
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Compatibility with E-prime may be achieved using a dedicated DAU equipped with a customised adaptor to collect trigger information.
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Adaptors, Safety, and Certifications
The disposable electrodes are biocompatible and suitable for research in a clinical setting. Certificates and reports issued for the Xtrodes system by accredited labs are available for the following tests: electrical safety, EMC, and biocompatibility.
Order and Pricing
The disposable electrodes and the DAU are commercially available by X-trodes.
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Users
Germany
Jena University Hospital, Jena
Humboldt University of Berlin​
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Japan
Macnica
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India
Trustwell Hospital, Bangalore
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Israel
Tel Aviv University
Bar Ilan University
Sourasky Medical Center
Inner Eye Ltd
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Singapore
National University of Singapore
USA
Icahn School of Medicine at Mount Sinai
University of Florida
Publications
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Luxembourg, N., Ben-Dov, D., Fekadu Marew, R., Teitelbaum, D., Vebraite Adereth, I., Hanein, Y. Capturing Dynamic Finger Gesturing with High-resolution Surface Electromyography and Computer Vision. J. Vis. Exp. (217), e67766, doi:10.3791/67766 (2025). Link
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Possti D, Oz S, Gerston A, Wasserman D, Duncan I, Cesari M, Dagay A, Tauman R, Mirelman A, Hanein Y. Semi-automatic quantification of REM sleep without atonia in natural sleep environment. NPJ Digit Med. 2024 Nov 28;7(1):341. doi: 10.1038/s41746-024-01354-8. PMID: 39609533; PMCID: PMC11605064. Link
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Funk, P.F., Levit, B., Bar-Haim, C. et al. Wireless high-resolution surface facial electromyography mask for discrimination of standardized facial expressions in healthy adults. Sci Rep 14, 19317 (2024). https://doi.org/10.1038/s41598-024-70205-z. Link
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Bara Levit, Paul F Funk, and Yael Hanein, Soft electrodes for simultaneous bio-potential and bio-impedance study of the face, Biomedical Physics & Engineering Express, Volume 10, Number 2, 2024. Link
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Ibrahim R, Ketko I, Scheinowitz M, Hanein Y (2024) Facial electromyography during exercise using soft electrode array: A feasibility study. PLoS ONE 19(2): e0298304. https://doi.org/ 10.1371/journal.pone.0298304. Link
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Ana Arché-Núñez, Peter Krebsbach, Bara Levit, Daniel Possti, Aaron Gerston, Thorsten Knoll, Thomas Velten, Chen Bar-Haim, Shani Oz, Shira Klorfeld-Auslender, et al., Bio-potential noise of dry printed electrodes: physiology versus the skin-electrode impedance. Physiological Measurement, 2023, Volume 44, Number 9. Link
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Liron Ben-Ari, Adi Ben-Ari, Cheni Hermon, and Yael Hanein, Finger gesture recognition with smart skin technology and deep learning, Flexible and Printed Electronics, Volume 8, Number 2, DOI 10.1088/2058-8585/acd2e8. 2023, Link
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