Artificial skin that can sense touch – allowing the wearer to ‘hold hands’ with a loved one on the other side of the world or feel a pat on the back from a teammate in the online game Fortnite – has been developed by scientists.
Described as an ‘epidermal VR’ system, the artificial skin consists of a six-inch-square sheet of thin, soft, flexible material, embedded with 32 tiny vibrating actuators.
The frequency and amplitude of each actuator can be adjusted independently to generate a discrete sense of touch at corresponding locations on the skin.
The artificial skin can comfortably stick to the curved surfaces of the skin without bulky batteries and cumbersome wires, according to Northwestern University researchers.
As well as adding new dimensions to long-distance relationships and entertainment, the technology could also provide prosthetics with sensory feedback and impart telemedicine with a ‘human touch’.
The artificial skin consists of a six-inch-square sheet of thin, soft, flexible material, embedded with 32 tiny vibrating actuators
Retired US Army Sergeant Garrett Anderson (left) shaking hands with his prosthetic arm while wearing Northwestern Universitys wireless patch, a new second-skin ‘virtual reality’ technology which duplicates the sense of touch
‘We are expanding the boundaries and capabilities of virtual and augmented reality,’ said Northwestern’s Yonggang Huang, who co-led the research.
‘By comparison to the eyes and the ears, the skin is a relatively underexplored sensory interface that could significantly enhance experiences.’
The patch, or ‘epidermal VR’ system, has helped US Army veteran Garrett Anderson feel sensations from his prosthetic fingertips after it was placed on his upper arm.
They felt more or less intense – depending on the firmness of his grip.
Anderson, who is now the outreach co-ordinator at the University of Illinois’ Chez Veterans Center, said: ‘Say that I’m grabbing an egg or something fragile.
‘If I can’t adjust my grip, then I might crush the egg. I need to know the amount of grip that I’m applying, so that I don’t hurt something or someone..’
He lost his right forearm 15 years ago when a bomb exploded under his truck during the Iraq War.
Father-of-two Anderson said: ‘It blew the entire engine out of the vehicle. Then shrapnel came through the vehicle and severed my arm, which was hanging on by tendons.’
He believes the device could also ‘trick’ his brain in a way that relieves phantom pain – and enable him to interact with his children in a new way.
Each individual miniaturised actuator measures just 18 mm in diameter and 2.5 mm thick. It resonates most strongly at 200 cycles per second, where the skin exhibits maximum sensitivity
He said: ‘My kids are 13 and 10, so I have never felt them with my right arm. I don’t know what it’s like when they grab my right hand.’
In another experiment a girl touched a screen displaying a video feed of her grandmother – who sensed it through having the device on her hand and arm.
A third test involved a person playing a combat-based video game while wearing several across his body.
The devices were triggered when a strike occurred on the corresponding part of the computer character.
Project leader Professor John Rogers said the thin, wireless system adds a sense of touch to any virtual reality (VR) experience.
Combining it with a VR headset would create more interactive and immersive gaming or entertainment experiences.
The wireless, touch-sensitive interface can softly layer over skin and can communicate information through mechanical vibrations
Prof Rogers, a bioelectrics pioneer at Northwestern University in Illinois, said: ‘People have contemplated this overall concept in the past, but without a clear basis for a realistic technology with the right set of characteristics or the proper form of scalability.
‘Past designs involve manual assemblies of actuators, wires, batteries and combined internal and external control hardware.
‘We leveraged our knowledge in stretchable electronics and wireless power transfer to put together a superior collection of components, including miniaturised actuators, in an advanced architecture designed as a skin-interfaced wearable device – with almost no encumbrances on the user.
‘We feel it’s a good starting point that will scale naturally to full-body systems and hundreds or thousands of discrete, programmable actuators.’
When video chatting from different locations, friends and family members can reach out and virtually touch each other – with negligible time delay.
Pressures and patterns can be controlled through the touchscreen interface of the smartphone or tablet.
The six-inc-square sheet-like prototype can comfortably laminate onto the curved surfaces of the skin without bulky batteries and cumbersome wires
Study co-leader Prof Yonggang Huang said: ‘You could imagine that sensing virtual touch while on a video call with your family may become ubiquitous in the foreseeable future.’
The actuators are only 12 to 18mm wide, 2.5mm thick and weigh just 1.4 grams. The tacky silicone polymer sticks to the skin without tape or straps.
Described in Nature, the device communicates through the same technology used in smartphones for electronic payments.
Prof Rogers said: ‘With this wireless power delivery scheme, we completely avoid the need for batteries, with their weight, size, bulk and limited operating lifetimes.
‘The result is a thin, lightweight system that can be worn and used without constraint, indefinitely.’
As people who have had amputations use the device, the experience could become more seamless.
Prof Rogers said: ‘Users develop an ability to sense touch at the fingertips of their prosthetics through the sensory inputs on the upper arm.
The actuators are only 12 to 18mm wide, 2.5mm thick and weigh just 1.4 grams. The tacky silicone polymer sticks to the skin without tape or straps
‘Overtime, your brain can convert the sensation on your arm to a surrogate sense of feeling in your fingertips. It adds a sensory channel to reproduce the sense of touch.
‘It could be very powerful for social interactions, clinical medicine and applications that we cannot conceive of today, beyond the obvious opportunities in gaming and entertainment.’
The researchers are already working to make the current device slimmer and lighter. They also plan to exploit different types of actuators, including those that can produce heating and stretching sensations.
With thermal inputs, for example, a person might be able to sense how hot a cup of coffee is through prosthetic fingertips.
Eventually, the devices could be thin and flexible enough to be woven into clothes. People with prosthetics could wear VR shirts that communicate touch through their fingertips.
And along with VR headsets, gamers could wear full VR suits to become fully immersed into fantastical landscapes.
Prof Rogers said: ‘Virtual reality is a very important emerging area of technology.
Currently, we’re just using our eyes and our ears as the basis for those experiences.
‘The community has been comparatively slow to exploit the body’s largest organ: the skin.
‘Our sense of touch provides the most profound, deepest, emotional connection between people.’