A team of researchers in China has developed a remarkable device to allow people with limited mobility to use computers and experience VR content by moving their eyeballs – and to power the gadget simply by blinking.
The team believes this has the potential to replace many current-gen systems that rely on external power and can cause eye strain. Its solution is described as being as light as regular eyeglasses, so they’re more comfortable than today’s bulky alternatives. It could be a compelling option for people with amyotrophic lateral sclerosis (ALS), which significantly affects their ability to use their limbs and fine motor skills.
The wearable system watches for minute eyeball movements and accurately translates them into whatever command makes sense contextually. You could move a cursor across the screen, turning your eyeball left to send the cursor in that direction. You could also swipe through text in a VR environment, or control the motion of your wheelchair and get where you want to go, all by moving your eyeballs.
The system’s primary wearable component is an incredibly thin, flexible layer of clear, skin-safe PDMS plastic, worn on your eyeball like a contact lens. Its main job is to rub against the eyelid during a blink to generate a small amount of static electricity. There’s also a special pair of eyeglasses with lenses that are coated with see-through sensors called substrate electrodes (made of a material called ITO). They are positioned to “catch” the electrical signals created by the contact lens as the eye moves in different directions.
This is based on the principle of a triboelectric nanogenerator (TENG), which is essentially a device that converts mechanical motion into electricity using static electricity (similar to the effect you see when you rub a balloon on your hair and it sticks to a wall).
The glasses are connected to a small signal processing system to filter out noise and amplify the signal received by the tracker, and also to translate those into specific commands, such as “turn left” or “move the cursor up”.
Image courtesy of the researchers
Here’s how it all works. Every time the user blinks, their eyelid rubs against the PDMS contact lens. This friction causes the surface of the lens to accumulate and store a large amount of negative static electricity. Once the lens is charged, it stays charged for a long time – even up to 10 minutes after a single blink. When the user moves their eye up, left, or right, this stored static charge moves along with the eyeball.
As the charged lens moves closer to the sensors on the glasses, it pushes and pulls electrons within those sensors through a process called electrostatic induction. This movement of electrons creates a tiny pulse of electricity. Because the sensors are arranged in a grid, the system can tell exactly which direction the eye is looking based on which sensor “feels” the electrical pulse.
The researchers tested the system on a live rabbit, as well as with a set of mechanized simulated eyeballs. You can see the latter in action above, where the eyeballs are being made to move sideways and scroll through text, kind of like how you might use this in VR.
“We were particularly surprised by how well the friction layer retained its charge in a biological setting on a rabbit’s eye,” said Yun-Ze Long of Qingdao University in China, who authored the paper on this tech that appeared in Cell Reports Physical Science last week. “We were also impressed by the system’s ability to maintain high accuracy even in noisy electromagnetic environments.”
It’s arguably the first such device to be powered by blinking. What’s particularly impressive about this project is that the choice of materials and hardware design already allow it to be biocompatible and fairly unobtrusive; I imagine this can be refined even further over time when it’s commercialized. The team hopes to see this tech feature in equipment for astronauts, intelligent driving systems, and a range of accessibility solutions for people with disabilities to use gadgets in the near future.
Source: Cell Reports
