Item: 9846 Ages:8+ Pieces:1Your robot's "eyes!"The Ultrasonic Sensor helps your LEGO® MINDSTORMS® NXT robot judge distances and "see" where objects are! Using the NXT Brick (sold separately), the Ultrasonic Sensor is able to detect an object and measure its proximity in inches or centimeters.
Item: 9843 Ages:8+ Pieces:1Your robot's "fingers!"The Touch Sensor reacts to touch and release, enabling your LEGO® MINDSTORMS® NXT robotic creation to "feel" like never before! It can detect single or multiple button presses, and reports back to the NXT Intelligent Brick (sold separately.)
Item: 9844 Ages:8+ Pieces:1Detect light intensity!The Light Sensor assists in helping your robot to "see." Using the NXT Brick (sold separately), it enables your robot to distinguish between light and dark, as well as determine the light intensity in a room or the light intensity of different colors.