Arguably, the most common reason builders stray back to LEGO from metal
build systems today is the lack of rapid-prototyping options. It simply takes more
time and more effort to screw together each piece, compared to simply snapping
them together. MATRIX approaches this problem with their unique Quick Connector
system. The Quick Connectors are two-part plastic pieces: a small pin and a sheath
for the pin to slide into. Pushing the pin all the way into the sheath opens the end,
locking the connector into place on a beam, plate, L-bracket, or any other holed
MATRIX piece. Quick Connectors provide a great alternative to screws and nuts for
prototyping, and for permanently connecting medium to low impact points on your
bot (Figure 7).
FIGURE 7. Quick Connectors can
be used to permanently attach low
Quick Connectors come
in three flavors.
The Quick Connectors come in three
flavors: short, medium, and long. Short
connectors are the perfect length to
connect two pieces of metal; medium
connectors fit three; and long connectors
fit a MATRIX beam plus a LEGO beam.
I also found that for temporary
prototyping purposes, you can get away
with using a larger than necessary Quick
Connector which is useful for connecting
four pieces of metal together; refer to
Figures 8A, 8B, and 8C.
I do a lot of iterating in designing my models, and DasBot was no exception.
The generally large size of the MATRIX models and L-shaped beams tend to make
getting your tools and/or fingers to the center of a complex model for adding
and removing pieces relatively easy. There were more than a few times during
DasBot’s design where the Quick Connectors significantly simplified the design
process. The single biggest advantage of the MATRIX Quick Connector system is
the ability to snap in from only one side of an assembly, whereas a screw and nut
combo requires being able to reach both sides. This saved me a lot of grief in
prototyping, especially with the compact parts of DasBot like the wheel
assemblies (Figure 9).
The Quick Connectors also look cool, and I found myself inclined to use them
in the front bumpers of DasBot not only due to the speed I could assemble them
in (each bumper took all of about 10 seconds to assemble), but for the aesthetic
value, as well. Like little black rivets, the Quick Connectors stand out on the silver
background of the beams and gusset plates, making for a very striking visual
FIGURE 9. Under the front wheels.
The best robots are simple and purpose-built, and
require a build system that is simultaneously robust, flexible,
and predictable — a very tall order. LEGO Technic and
MINDSTORMS have long been lauded as the gold standard
of small-scale robotics build systems, but the fact of the
matter is they're toys — the average student/hobbyist
graduates from LEGO to a metal platform, and based on
Technic's intuitive build system, it should be no surprise that
where TETRIX borrows design elements from Lynxmotion's
(also cool) Servo Erector Set (Figure 10), MATRIX aims to