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The Learning Brick Sorter • Masterpiece 2 43

to the number Y, if the result is greater than Z then do this, otherwise do that, and so
forth.This process is defined as an algorithm.A more formal definition of an algorithm is a
step-by-step problem-solving procedure, especially an established, recursive computational
procedure for solving a problem in a finite number of steps. How can we turn this rigid
structure of equation-based logic into a process that is flexible enough to learn from
experience? The answer is data. In fact, data is the key to storing knowledge that comes
from experience. In most of AI programs, the algorithm remains the same, but exhibits
different behaviors according to the data it finds in its knowledge base.
AI is a very complex matter, being at the top of computer science hierarchy for both
for the ambitiousness of its goals and for the sophistication of the techniques involved.
Genetic algorithms, genetic programming, artificial neural networks… all these techniques
lead to amazing results, but require the mastery of many mathematical instruments to be
fully understood and used.The Learning Brick Sorter uses a much simpler technique, but it
shows us how even an elementary learning mechanism greatly expands the flexibility of a
robot. In fact, it can be trained to distinguish any three different colors (provided that they
return well-separated light readings) and to place them in three bins according to your pref-
erences.You can change the colors, or the order of the bins, and after a short training ses-
sion the Brick Sorter will be ready to work with the new specifications.

Building the Learning Brick Sorter

Without further ado, let us begin with the building instructions for the Learning
Brick Sorter.

The Body

First, we are going to build the main body of the Brick Sorter.The Body sub-assembly
supports the Arm sub-assembly (built later on) and provides the Arm sub-assembly with
the capability to perform rotary motions in order to reach the bins where the bricks are
sorted.The double pulley with pins, visible on the right of the model, will interface with