Researchers at the Army Research Office developed a vibrating belt with eight mini actuators — “tactors” — that signify all the cardinal directions. The belt is hooked up to a GPS navigation system, a digital compass and an accelerometer, so the system knows which way a soldier is headed even if he’s lying on his side or on his back.
The tactors vibrate at 250 hertz, which equates to a gentle nudge around the middle. Researchers developed a sort of tactile morse code to signify each direction, helping a soldier determine which way to go, New Scientist explains. A soldier moving in the right direction will feel the proper pattern across the front of his torso. A buzz from the front, side and back tactors means “halt,” a pulsating movement from back to front means “move out,” and so on.