involve other “cable” management
devices. You can get plastic clamps of
various styles and sizes that are
designed to hold bundles of wire and
cable together. A single eyelet is used
to anchor the clamp. Use a large
clamp for round-case motors, and
secure the clamp in place by drilling a
hole into your robot’s base; secure
with a nut and screw. Use a clamp on
each end of the motor to keep it
stationary. Depending on your goals,
design, and the weight of your motors
and other parts, you may also find a
thick rubber band to be a useful fastener. If you can’t wrap the band
around the object that you want to
secure, thread the ends through holes
in the base and then use wire twist
wraps (the kind they use in grocery
stores in the produce section) to keep
the band taut and in place. The
disadvantage of this method is that
you may need to make fairly large
mounting holes in the base in order
to accommodate the larger thickness
of the rubber band.
Toys and Household
Materials
I’m far from the purist and don’t
mind reusing things like LEGO bricks
in my prototypes. Construction toys
are excellent sources of cheap and
reusable parts. One method you can
try is using LEGO extras and discards
for making customized accessories.
The snap-on nature of LEGOS
allows you to easily reuse them for
different prototype projects. Glue
(double-sided tape works too) some
LEGO plates onto your base and then
use Technic beams and other LEGO
parts for attaching things to the
plates. For example, you might glue
the flat bottom of a standard R/C
servo motor to some LEGO blocks.
(It’s okay to use glue here because
you’re able to re-use the motor as
much as you’d like, because you can
simply pull it off the LEGO plate when
you’re done.) Use the servo motor to
quickly and effortlessly attach a sensor
turret to your base. Just add a bracket
and ultrasonic or infrared sensor on
top of the servo, snap the servo into
place on the base, and you’re done.
The same concept works for other
components as well, such as compass-es, accelerometers, microcontrollers,
speakers, lights, you name it. The idea
is to mount the part to one or more
accommodating LEGO pieces,
ensuring that everything is aligned.
This allows you to press one LEGO
part into the next.
The idea doesn’t stop with LEGO
Art Supply.com is an online source for sheets of foam clad board, corrugated
plastic, and other materials useful in creating robotic prototypes.
beams, plates, and other parts. You
can also use plastic or metal construction set pieces from an Erector Set.
One benefit here is that if you make
accessories using these parts, they are
easily transferred to full robots once
you have successfully prototyped the
design. For instance, you can
permanently mount a short Erector
Set beam to a servo motor and use
it as a mounting bracket for a
cardboard-based prototype. Use
screws to secure the bracket to the
base. Once you have everything
worked out, simply remove the
bracket from the cardboard base and
re-attach it to your robot’s permanent
base. Finally, be on the lookout for
common household items that can be
repurposed for quick and easy robot
protos. The ubiquitous Popsicle stick —
sold in bags by the hundreds in craft
stores — is a good example. Use them
to make temporary bumper pieces for
your robot, or stack them and poke or
drill small holes in them to make
mounting frames for your electronics.
You can also use small plastic jars
or cut-up water bottles for housing
speakers, buzzers, LEDs, and other
small parts, plus, the caps of water
bottles for undercarriage “skids” (for
two-wheeled robots). Remember: The
idea isn’t to make a permanent robot
that will withstand hours and hours of
experimenting, but something that
will hold together long enough for
you to find the bugs in your design,
and make it better.
Sources
Online is a great source to find
items such as laminated foam and
plastic, but shipping can get expensive
because of the size. Check your local
home improvement or hardware store,
as well as most well-stocked craft
supply stores for things like foam
board or corrugated plastic sheet. If
you can’t find what you need locally,
try out some of the resources here to
use in your next robot prototype.
Art Supply.Com
www.artsupply.com
Online repository of art supplies,
76 SERVO 07.2009