“Skin VR”, ultra-thin and wireless, a vivid experience for the metaverse.
Researchers develop a second skin to provide a tactile, vivid, and ‘personalized’ experience designed for the virtual world.
Improving the virtual experience with tactile sensation has become a hot topic, but today’s devices typically remain bulky and tangled in wires. Researchers at the City University of Hong Kong (CityU) recently developed an advanced wireless haptic (tactile) interface system, called WeTac, to be worn on the hand, which features soft and ultra-thin characteristics and collects customized tactile sensation data to provide a vivid experience in the metaverse. The device was designed to allow users to perceive virtual objects in different scenarios, such as grabbing a tennis ball in sports training, touching a plant, etc.
The system has application potential in games, sports and skill training, social activities and remote robotic controls. “Haptic feedback has great potential, along with visual and audible information, in virtual reality (VR), so we tried to make the haptic interface thinner, softer, more compact and wireless, so you can use it freely on the hand, like a second skin ,” said Dr. Yu Xinge, a professor in CityU’s Department of Biomedical Engineering (BME), who led the research. The research results have been published in the scientific journal Nature Machine Intelligenceas the cover article, titled “Encoding of tactile information in hand via skin-integrated wireless haptic interface”.
Existing haptic gloves mostly rely on bulky pumps and air ducts, powered and controlled through a bunch of cables and wires, which severely hamper the users’ immersive experience. The new WeTac overcomes these shortcomings with its soft, skin-integrated wireless electrotactile system . The system consists of two parts: a miniaturized soft driver unit attached to the forearm as a control panel , and a hand patch with hydrogel-based electrodes as a haptic interface.
The entire driver unit weighs just 19.2g and is small enough (5cm x 5cm x 2.1mm) to fit on the arm. It uses Bluetooth low energy (BLE) wireless communication and a small rechargeable lithium-ion battery. The hand patch is only 220 µm – 1 mm thick, with electrodes on the palm. It features great flexibility and provides effective feedback in various poses and gestures.
High pixel density for a personalized experience
“Electrotactile stimulation is a good method to provide users with effective virtual touch,” Dr. Yu explained. “However, as individuals have different sensitivities , the same feedback force might be felt differently by different users’ hands. We must, therefore, customize the feedback parameters accordingly to provide a universal tool for all users and eliminate another major bottleneck of current haptic technology”.
WeTac’s ultra-soft feature allows you to easily map threshold currents for individual users, to determine the optimized parameters for each part of the hand. Based on the customized threshold data, electrotactile feedback can be delivered on demand to any part of the hand in a suitable intensity range to avoid causing pain or being too weak to feel. In this way, virtual tactile information, including spatial and temporal sequences, can be faithfully reproduced throughout the hand. WeTac patches are worn on the hands to provide programmable spatio-temporal feedback patterns, with 32 pixels of electrotactile stimulation on the palm of the hand instead of just the fingertips. The average center-to-center distance between the electrodes is approximately 13mm, for wide coverage. The device has several built-in safety measures to protect users from electric shock, and the temperature of the device is kept in a relatively low range of 27 to 35.5°C to avoid causing thermal discomfort during continuous operation .
