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The Learning Brick Sorter • Masterpiece 2 89

Tuning and Testing the Learning Brick Sorter

Now that the building phase is finished, you want to be sure that everything is connected
properly and works as expected.
First, check to make sure the mechanical connections of the Brick Sorter are opera-
tional. Verify that the Arm sub-assembly is pointed toward the Pickup Stand sub-
assembly. When the arm is lowered, the hand must align exactly with the yellow tile on
the stand. If this is not the case, manually rotate the axle that operates the turntable (be
sure that the RCX is switched off) until the arm is in the described position.At this
point, the pin mounted on the pulley should close the touch sensor mounted on the
Pickup Stand sub-assembly.This pin should be a bit off center of the sensor, as it appears
in Figure 2.1.

Figure 2.1 Pin Alignment for the Activation of the Pickup Stand Touch Sensor

If your pulley is not in this position, you should locate the gear assembled in Body
Step 15, pull the gear back a bit to disengage it from the worm gear (there’s no need to
remove the body from the baseplate), rotate the pulley until it reaches the position of
Figure 2.1, and then replace the gear back against the worm gear.
Now we are going to test the connections of the motors and the pneumatic valves.
Apply a small amount of pressure to the pneumatic circuit using the manual pump, and
then switch the RCX on.Turning Motor A on in a reverse direction, the arm should
rotate toward the bins. When the motor runs in a forward direction it should go back
toward the Pickup Stand. If during the testing process you experience behavior opposite
of what was just stated, check the cabling of the motor and correct it if necessary.
With a brief impulse to Motor B in the forward direction, the hand should open,
while in reverse direction it should close. If this doesn’t happen, check the cabling and the
pneumatic tubes.