Cornell University researchers have found a new way to give robots a sense of touch. Instead of relying on sensors that measure resistance, like those used to prevent elevator doors from trapping your outstretched arm, the team created a robot hand that “feels” things by analyzing light.

The hand accomplishes this with sensors built into its “body” that measure optical wavelengths. If the light is distorted, the hand can reason that it must be touching something. If it isn’t, the hand knows it’s not in contact with anything. But it also knows far more than just a binary touching” or not touching.”

Researchers at Cornell University’s Organic Robotics Lab have announced that the robot can use this method to differentiate between objects, guess what kind of material it’s touching, and measure how firm a surface is. Their work was published in a research article in the December 6 edition of the journal Science Robotics.

“Most robots today have sensors on the outside of the body that detect things from the surface,” says doctoral student Huichan Zhao, lead author of the paper. “Our sensors are integrated within the body, so they can actually detect forces being transmitted through the thickness of the robot, a lot like we and all organisms do when we feel pain, for example.”

You know how a tomato gets softer as it becomes more ripe? Well, now this mechanical hand does, too:

These are some of the robot hand's capabilities.

Here’s how the robot presses to detect softness, in a video released by the researchers:

Perhaps it could also be used to allow robots to feel more in touch with their surroundings. It’s the age of humanoid robots, from the possibly-genocidal Sophia to the “robot goddess” JiaJia, and people around the world are trying to make them even more lifelike.

Those efforts take different forms. Florida’s Institute for Human and Machine Cognition, for example, has been trying to make robots more agile by giving them a better sense of balance. This would help the robots walk around more like humans do.

Meanwhile, University of Tokyo researchers took inspiration from the human body to develop a better cooling system for their humanoid robot, Kengoro. They made it sweat. Now it doesn’t have to worry about overheating when it does push-ups for 11 straight minutes.

Just look at it go.

Cornell’s researchers said their robot hand is currently just a prototype. They want to make it even better by using more sensors, increasing the hand’s sensitivity to light, and training it with machine learning techniques by collecting lots of data. This will culminate in a smarter and more sensitive device.

“We believe that the easy fabrication, low cost, chemical compatibility, and high repeatability of the developed stretchable waveguide sensors will benefit the field of robotics,” the researchers said, by making better soft robot bodies and developing “skins” for more rigid constructs.

“We feel the world by the sense of touch, mostly through our hands. Hence, the loss of a hand not only means losing the ability of grasping and manipulation but also closes a door to sensory perception — hand amputees can no longer touch and feel through their fingers.

Photos via Cornell University, IHMC Robotics / YouTube, IEEE Spectrum / YouTube