Touch is arguably the most underappreciated of all our senses. Our fingertips can give us amazing and subtle detail about the surface in front of us- is it rough? soft? fluffy? Your fingertips can tell you if you’re touching paper or leather without a second thought. It is now commonplace to hear someone’s voice and see their face from the other side of the world, yet there is currently no equivalent possibility for virtual touch. Imagine if you could feel the texture of clothes when shopping online, or a virtual reality where you can pick up an object and feel it in your hand. Imagine if a surgeon could feel the texture of the surface at the other end of keyhole surgery– even from another country.
When you touch a surface, the interaction is fundamentally electromagnetic. Drawing your finger across a surface, your brain interprets the varying signal from your finger as the texture or topography of the surface. People at Disney Research have utilised this fact to produce Tesla Touch, a flat, unmoving surface that can change the way it feels by clever manipulation of the static charge on the surface. An oscillating charge is applied to the surface and the shape and frequency of the wave is interpreted by the brain as a texture on the surface. A triangular waveform gives the impression of a rough surface for example, whilst a square wave can imitate a surface topography. The speed and location of the person’s finger can be measured and the oscillation frequency altered in real time to give the impression of a surface with evenly spaced bumps. This is all achieved without any actual spatial variation of charge on the surface or any physical movement.
There are other emerging technologies in the wearable tech market with greater relevance for virtual reality and gaming. These include a haptic glove that puts pressure on your hand via inflatable bladders, so that you can feel the boundary of a virtual object and can feel like you are holding it. Another approach to a similar problem is using an exoskeletal hand to provide force feedback, to stop you from passing your hand right through a ‘solid’ virtual object.
There is however a way to go before you could feel the fabric of something you’re buying on your smartphone. This technology can imitate a general surface texture, and the technology exists to measure the relevant characteristics of a real surface, but there remains a gulf between measuring the surface and translating that into a waveform to represent it. There are also other aspects of touch that this neglects. For instance, the only difference between polished steel and a smooth plastic may be that steel feels cold due to its high thermal conductivity. A virtual steel that didn’t have this property would be jarring to the senses.
From a single touch with the tip of your finger, you perceive texture, pressure, temperature and motion. Haptic feedback may have a long journey ahead to emulate all of this, but it is great to see innovations like this taking the first steps on that journey.