These walls might as well have ears. Eyes, too. Researchers have found an inexpensive way to turn walls into giant touch screens that can also sense what a person is doing nearby and when the TV, microwave, or computer are turned on and off. These interactive walls could make electronic personal assistants, such as Alexa or Cortana, much smarter, enabling them to assist better in managing a household. Imagine, for example, a TV that turns on as you sit down on the sofa, or Alexa letting you know that your kids have snuck into the living room to play video games.
The first step was converting a wall into an antenna. The engineers first taped a grid onto the wall, then painted over it with a water-based compound containing nickel. They removed the tape, which left behind a pattern of metallic diamonds that act as electrodes. They then connected the electrodes to a computer and painted the wall with standard latex paint, hiding any sign of its new capabilities.
Touching or moving an arm or limb close to the wall changes the wall’s electrostatic fields, just as a finger touching an iPad does, the group reports this week at a conference on computing in Montreal, Canada. TVs, computers, and other electronic devices generate distinctive electromagnetic fields, which the walls also sense.
Eventually such walls—which the team created for $20 per square meter—could feed this information to electronic personal assistants, making them true household helpers.