Seeing with Ultrasonics
The LEGO MINDSTORMS Ultrasonic sensor is another way to give your robot the gift of sight. Unlike the Light sensor, which detects reflected light, the Ultrasonic sensor works by sending out a sonic wave that reflects off objects in front of the sensor. The wave reflects back to the sensor, which determines its distance from the object based on the amount of time it took the sonic wave to return. This is similar to the way that animals such as bats see at night.
The sonic wave has a much longer range of detection than the Light sensor. But you need to be careful with the way you use the Ultrasonic sensor at robot events. Various factors affect how the sensor detects objects in its environment.
How It Works ...