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Interactive Servo Motor
Technology
The three Interactive Servo Motors provide the robot 
with the ability to move. Using the Move [Move] 
block automatically aligns their speed so that the 
robot moves smoothly.
Built-in Rotation Sensor
The Interactive Servo Motors all have a built-in Rotation 
Sensor. The rotational feedback allows the NXT to control 
movements very precisely. The built-in Rotation Sensor 
measures the Motor rotations in degrees (accuracy of +/- one 
degree) or full rotations. One rotation is 360 degrees, so if 
you set the Motor to turn 180 degrees, the hub will make half 
a turn.
View
Test the Rotation Sensor’s ability to measure distance.
Connect the Motor to the NXT.
Select View [View] in the NXT display.
Select the Motor rotations 
icon.
Suggestions for use
The built-in Rotation Sensor in each motor along with the 
Power confi guration in the Move or Motor blocks in the 
Software (see page 53-55) allow you to program different 
speeds for your Motors and move the robot accurately.
Select the port in which you have placed the Motor.
Now try to attach a wheel to the Motor and measure the rotations by pushing the 
wheel over the fl oor.