A team of researchers from Saarland University and the INM-Leibniz Institute for New Materials have published details of a low-cost rapidly-fabricated skin-conformal sensor system for physiological interfacing — including "arousal monitoring" during immersive virtual reality use.
"Advances in rapid prototyping platforms have made physiological sensing accessible to a wide audience. However, off-the-shelf electrodes commonly used for capturing biosignals are typically thick, non-conformal and do not support customisation," the team writes in the paper's abstract. "We present PhysioSkin, a rapid, do-it-yourself prototyping method for fabricating custom multi-modal physiological sensors, using commercial materials and a commodity desktop inkjet printer."
Not to be confused with the products of the Physioskin company, which creates hardware for thermosclerosis treatment of veins, the PhsyioSkin system "realizes ultra-thin skin-conformal patches (∼1 μm) and interactive textiles that capture sEMG [surface electromyography], EDA [electrodermal activity], and ECG [electrocardiogram] signals. It further supports fabricating devices with custom levels of thickness and stretchability."
While the sensors are smart, they're also easy to make and use: The sensors themselves are created in just 5-20 minutes using a desktop inkjet printer and simple lab equipment, and can be used with commercial off-the-shelf physiological sensing tool kits — meaning there's no need to construct complex custom electronics or write any code.
"Evaluation results show that the sensor patches achieve a high signal-to-noise ratio," the researchers claim. "Example applications demonstrate the functionality and versatility of our approach for prototyping a next generation of physiological devices that intimately couple with the human body."
Those applications proved the sensors' worth in three areas: A fitness-tracking textile vest, which can be worn during exercise and removed afterwards; a temporary tattoo designed to monitor the subject's heart rate; and, somewhat cheekily, a polydimethylsiloxane (PDMS) patch "used for arousal logging in virtual reality environments."
More information is available in the team's paper.