FIGURE 10. A C-Channel from
Lynxmotion's Servo Erector Set.
FIGURE 11. MATRIX and LEGO
geometry are almost identical.
FIGURE 12. This 4-8-10 triangle has
seven holes between its bottom
vertices, but eight units.
bring the competition to the next level by very closely
replicating the geometry of LEGO Technic and its adherence
to an 8 mm pitch hole pattern.(Figure 11).
Like LEGO Technic, MATRIX is designed such that any
multiple of a 3-4-5 triangle (in MATRIX units/LEGO studs)
will align perfectly with the grid. To create a 3-4-5 triangle
with MATRIX, multiply three, four, and five by a common
coefficient, then subtract one from each of the products.
The three resulting numbers represent how many holes you
should have between each vertex of your triangle — not
including the vertices themselves (Figure 12).
Suddenly, it becomes very easy and predictable to
incorporate angles into your designs, both for structural
integrity and for aesthetic purposes. This convenience is
amplified by the fact that MATRIX and LEGO structures line
up perfectly, so even your angular designs can integrate
seamlessly across platforms.
Why Subtract One?
When we multiply three, four, and five by a common
coefficient, the result is the number of MATRIX units that
should be between each vertex of the triangle. The problem
with that calculation is that it means we’re not counting
the holes themselves in the MATRIX pieces, but instead,
we’re counting the spaces between the holes. By
subtracting one from our result, we can count the holes
instead of the units.
Also helpful is the myriad of shapes and sizes of
MATRIX beams and plates which allow great flexibility in
design, without overwhelming you with too many choices.
L-beams and C-channels are best used for creating a sturdy
frame, with flat beams and gusset plates filling the roles of
secondary reinforcements, low impact structural elements,
and alternative spacers — often a better choice than the
included plastic washers.
I wanted to take advantage of the ease of creating
angles while staying on the grid with MATRIX, and so the
entire front portion of DasBot is sloped, creating a very
appealing aesthetic look. Because the geometry lines up
42 SERVO 05.2013
perfectly, the ramps are actually quite well-reinforced,
making for a design that’s not just talk.
One of the biggest
shortcomings of the
VEX and TETRIX
platforms, in my
opinion, is their lack
of scalability. Their
beams and C-channels
have only one width,
and all robots must be structured around that. Larger VEX
models tend to sway due to their thinner beams, and it is
very difficult to build a compact TETRIX model due to their
exceptionally large C-channels. (Figure 13.)
MATRIX attempts to solve the scalability problem by
offering two widths of L-beams and connectors: standard
and XL. Standard beams and connectors are compact and
sturdy for their size. They can be used to create small to
medium models with ease, much like the beams of VEX.
XL parts, on the other hand, are the equivalent of the
behemoth TETRIX C-channels, and are also similar to TETRIX
in their impressive weight capacity. XL MATRIX parts are
sold separately and are best used for larger models like
those built for FTC.
FIGURE 13. It's difficult to
design compact TETRIX bots.
Gears That Fit
If there’s a single element of the MATRIX Robotics
system that I am most impressed with, it’s gotta be the
gears. The lightweight (but sturdy) polycarbonate makes
To find MATRIX distributors
FIRST Tech Challenge