Ultrasonic Sensor
View
Test the Ultrasonic Sensor’s ability to measure 
distance using View [View].
Connect the Ultrasonic Sensor to the NXT.
Select View in the NXT display.
Try to measure the distance to an object. Move the object closer and 
see the different readings.
Select the Ultrasonic Sensor icon.
Select the port in which you have 
placed the sensor.
Technology
The Ultrasonic Sensor enables the robot to see 
and recognize objects, avoid obstacles, measure 
distances, and detect movement.
The Ultrasonic Sensor uses the same scientifi c 
principle as bats: it measures distance by 
calculating the time it takes for a sound wave to hit 
an object and come back – just like an echo.
The Ultrasonic Sensor measures distance in centimeters and 
inches. It is able to measure distances from 0 to 2.5 meters 
with a precision of +/-3 cm.
Large-sized objects with hard surfaces provide the best 
readings. Objects made from soft fabrics, from curved 
objects (e.g. a ball), or from very thin and small objects can 
be diffi cult for the sensor to read.
Suggestions for use
You can add the Ultrasonic Sensor to an NXT 
model and then program the model behavior to 
change when the Light Sensor is activated.
Programming ideas using the Ultrasonic Sensor 
are included in the Robot Educator.
Note: Two Ultrasonic Sensors 
in the same room may 
interfere with each other’s 
readings.