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The Learning Brick Sorter • Masterpiece 2 71

Final Step 0

Locate the Body sub-assembly
and the Pickup Stand sub-assembly.
Attach the Pickup Stand sub-assembly to the
Body sub-assembly by sliding the #10 axle through the
first hole of the gray 1x16 beams protruding from the
Body sub-assembly and the bottom holes of the Pickup
Stand sub-assembly.

Bricks & Chips…

To Use Or Not To Use A Rotation Sensor?
The combination of the rotating pulleys with pins attached to the Body sub-
assembly, paired with the touch sensors mounted on the Pickup Stand sub-
assembly, creates a model similar in function to LEGO rotation sensor. You might
wonder why I did not use the original LEGO rotation sensor? Unfortunately, the
reliability of LEGO rotation sensor is directly related to the speed of the rotation.
If the rotation sensor is operating at a low rotation, then the reliability of the
rotation sensor is adversely affected. There are both hardware and software solu-
tions for this; however, for the purpose of this project, I did not wish to force
readers to modify their rotation sensors or use some specific alternative program-
ming language. This building process solves this problem, and has the benefit of
learning a technique to emulate a rotation sensor when that solution is not avail-
able for use.
If you want to know more about the previously mentioned problem that
affects the rotation sensor, please refer to Philippe Hurbain’s very well-docu-
mented Web page: www.philohome.com/sensors/legorot.htm