Test Lego Motor

For this experiment, we also need to know how to use the Lego Motor. First of all, we need to define forward rotation of Lego Motor as shown in Figure 1:

           Figure 1: Definition of forward rotation, taken from Reference 1

We need to understand the input wire for controlling Lego Motor, so the details are in the follows (Reference 1):

Cable Color                                  Functions
White                                     Motor Power Supply (Use)
Black                                     Motor Power Supply (Use)
Red                                        Rotation detector supply
Green                                     Rotation detector supply
Yellow                                   Rotation detector output 1
Blue                                       Rotation detector output 2

From above information, we know that the white and black wire determines the direction of rotation. Therefore, we only use these two wires in this experiment. The test results are as shown in follows:

Input Signal (White, Black)                        Rotation
10                                                            Forward
01                                                            Backward
00/11                                                       Stop

We use 10, 01 for rotation and 00 for stop in this experiment.





Reference:

1. Input and Output of Lego NXT Servo Motor, http://trivox.tripod.com/lego-nxt-motor-input-output.html