come into play for the robot
to move at all.
The mounting of the
smallest sensor or simple
servo drive motors requires
some mechanical aptitude.
For those with minimal
mechanical skills, robot kits
such as the LEGO
Mindstorms or Parallax BOE-Bot are a great way to go.
However, sooner or later, if
you don’t hang up your
robot builder’s hat and just
give up, you’re going to
want to design and build
As Dave mentioned, you do not have to go to one of
the big box stores since your local hardware shop might
offer a lot more variety in unique fasteners and bracketry.
Flexible dryer hose makes a very good robot arm
covering. Drapery rods and associated hardware are a good
source for fastening brackets, as well as pulleys, slides, and
metal extrusions. Door hardware, PVC and similar piping in
plumbing, plumbing fittings, the hundreds of drawers filled
with every fastener imaginable in the hardware section, and
unique items in electrical will fill many of your needs.
The Simpson Strong Tie lumber joist hangers and
fastening brackets section has steel Ts, Ls, and many other
heavy-duty brackets that can assist in holding a robot’s frame
together. Or, they can actually form a robot chassis.
Plastic sheeting, aluminum, and steel L and H extrusions,
steel and brass rod stock, and threaded rod stock can be
used to form a complete robot framework. Ls make very
good fastening brackets for the long extrusions forming the
frame. It is so much easier to bolt angle and square
aluminum extrusions together to form a robot’s frame than
to weld them.
Good welds that result in a truly square framework are
difficult as the extrusions many times are tweaked from the
heat of the welding process, and disassembly is very difficult
if you want to modify things.
One surprising area of a builder’s supply is the counter
and floor tile area. Tile setters frequently use metal tile
transition strips of aluminum shown in Figure 8. Made by
Schluter and other tile setter accessory companies, these
strips have a very nice set of holes that look like the side of a
large steel beam used in construction. They come in six foot
and longer lengths, and many are L shaped with a 1” to 1-
1/2” width. The holes were made to be embedded in the
tile’s adhesive out of sight, with only the edge showing.
These strips make great robot arm structures or to cover the
rim around the edges of two robot base metal plates to
partially hide the electronics inside.
The power tool section of any hardware store just might
have the ideal motors for your next robot. I have seen many
small combat type robot builders use cordless drill motors
FIGURE 8. Aluminum tile
transition metal strip.
FIGURE 9. Hacking a kid's electric scooter.
FIGURE 10. A
and the associated
gearing as drive
motors. You certainly do not want to destroy a top-quality
drill to rob it of its motor, so go to Harbor Freight or similar
stores to locate a basic drill for your project.
I have seen cheap drills with a charger and NiCad
battery pack for around $10, but remember, you get what
you pay for. You might use the battery pack, but the
variable speed control and chuck (as well as the plastic case)
will do you no good. A much better bet is checking out
Hobby and Craft Shops
Leaving the hardware store, wander over to your local
hobby shop. Sure, you will find a lot of R/C equipment and
electronic speed controllers, but look at the off-road car
parts instead. Knobby tires/wheels with associated shafts,
shock absorbers, and mounting hardware have been used
for thousands of medium to large robots. Small model
airplane wheels make good tires for small robots, but few
have any sort of gripping power like the off-road tires, and
applying power to them is a bit more difficult.
Motors and drive systems for cars are good but some of
the outrunner and brushless motors used in airplanes,
helicopters, and quadcopters are not the best for robot
motors. Hobby shops often have small bins of square and
round tubular brass and aluminum stock that are just great
for smaller robots that have intricate mechanical
Look at the racks of servo linkages, tiny hinges, rods,
and special servo horns for great parts for small robots. Craft
stores also have parts applicable to robot building such as
small tools, wood, plastic and brass plates, adhesives, and all
sorts of lacquers and coatings.
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