Smart leg brace locks and unlocks knee automatically

The sensor hardware.

NeLo is a flexible leg brace that uses sensor data to help polio patients—and people with sports injuries—lock and unlock their knees when walking.

The brace is designed to switch between being flexible and rigid depending on whether the person wearing it is walking, standing, or sitting—when the person's weight needs to be supported on the braced leg it becomes rigid, but it then loosens when the person bends or sits down.

It looks much like a flexible material leg brace, but is connected to two sensors—a foot pressure sensor and a gyroscope worn near the hip—which pair with an Arduino board to analyze the person's position. This data is fed to servo motors that loosen and tighten the material in order to switch between rigid and flexible using a mechanism inspired by a Chinese finger trap. This mechanism, which required the inside of two pieces of fabric to be lined with a sandpaper-like material, allowed for the system to work using relatively small, low-powered motors.