The sensors found in smart phones and Nintendo Wii controllers have migrated into Black & Decker’s cordless 4v MAX Gyro ($40), billed as the world’s first motion-activated screwdriver. Tilt it right by a mere quarter of an inch and it screws clockwise to tighten; left, and it turns counterclockwise—all thanks to an internal gyroscope that senses wrist motions, which are measured by a small microprocessor that turns those movements into changes in the drill’s speed and direction.