including PWM (pulse-width modulation) cables to connect
the servos to a controller, and some special wires to
connect the mightyZAPs to each other. One unique feature
of the mightyZAPs that we think is pretty awesome is the
ability to daisy chain several motors together. It’s
only slightly unnerving to see the servos move in
unison, like a small mechanical version of The
Human Centipede. All unnervingness aside, this
would be a great way to craft some very
sophisticated mechanisms with very simple wiring
A multi-stage arm could be controlled with the
single tilt of a joystick, or a symmetrical mechanism
that uses two servos acting in concert could be kept
perfectly in sync. It’s a cool feature and it’s nicely
executed — both ports are right next to each other,
keeping the wiring clean and compact.
The main annoyance with using the VEX system
as our prototyping platform was the vexing issue of
the funky ports on the control unit. The VEX control
unit sported sockets; so did the PWM cables that
came with the mightyZAPs.
Fortunately, we had run into this issue with the
VEX kit often enough that we were as well prepared
as the final girl from You’re Next. We had male-to-male PWM cables.
We wired up the servo motors in series, and
when we turned on the bot, our radio’s bright LEDs
on the servos flashed to life. As we tilted the
joystick, the rods extended and retracted in concert.
The speed of the 40N servo was a bit faster than the
100N servo, so instead of being perfectly in sync,
the servos appeared to do a coordinated dance.
Satisfied with the initial test, we were excited to see
how we could incorporate the motors into some fun
We tend to avoid using servos in our projects
(and use them begrudgingly when we have to)
because of two main headaches: mounting things to
the servo shaft; and mounting the servo itself. We find
servo horns fiddly and annoying, like the insufferable
character that always has you rooting for Leatherface or
Freddy Krueger. The horns are usually plastic and fragile,
with an inscrutable pattern of holes that seems more
designed to be part of some demonic ritual than to
actually be helpful for mounting.
Plus, the mounting points on the servo body
itself are a bit awkwardly spaced, and usually require
you to break out the calipers to figure out the
necessary dimensions because good technical
drawings of basic servos can be hard to come by.
The mightyZAPs have elegant solutions for both
The shafts of the linear actuators have threaded
holes in the end, and the mightyZAPs come with
some end-effector pieces to thread in. One small
metal piece has a through hole, allowing the servo
to firmly grip whatever you want it to push or pull
around. The shaft on the end-effector is a decent
50 SERVO 10.2017
CREATING A LIFTER.
WIRING UP FOR SOME BENCH TESTING.
OUR VEX ROBOT, RISING FROM THE DEAD AGAIN.
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