The right paint can add pizazz to your walls—and now it can also make them smarter. Researchers recently converted a wall into an outsize trackpad and motion sensor by using low-cost conductive paint to create a large grid of electrodes.

Such a smart wall can sense human touch and track gestures from a short distance. It can also detect the locations of appliances and whether they are switched on. The technology could someday turn on lights when a person enters a room, track a player's motion in an interactive video game or monitor a child's television use. “Walls are everywhere, so why not turn them into sensors for smart homes?” says Yang Zhang, a computer science doctoral student at Carnegie Mellon University, who helped to develop the concept.

To create the high-tech surface, Zhang and his colleagues applied painter's tape in a lattice pattern to a 12-by-eight-foot wall, then coated it with commercially available conductive nickel paint. Removing the tape left a pattern of diamond-shaped electrodes, which the researchers connected using a grid of thin copper tape strips. They affixed a vinyl sticker in the middle of each diamond to insulate the electrodes from one another. Finally, they wired the strips to a custom-built circuit board and covered the wall with standard latex paint. The entire project took four hours and cost less than $200. In theory, Zhang says, “anyone can use the technique to make a wall smart.”