FIGURE 13. Yujin
78 SERVO 04.2013
Toys are unique — especially electrically driven or electronic toys.
A toy robot arm might have five axes of motion, whereas an industrial
robot with similar capabilities might cost $20,000. The toy industry
can accomplish some amazing feats of technology at 0.1% the cost of
a similar industrial product. Look at toy cars and toy tanks for the
rubber tires and treads that will cost a lot less than products at a
robot store. Another area of interest is standup ‘Razor’ type scooters
with electric drives. Figure 9 shows a simple hacked kid’s scooter
motor/wheel drive system. Many operate from six or 12 volt SLA
batteries that are available everywhere.
Figure 10 shows a souped-up scooter motor from the
hackaday.com site that runs at 1,480 watts from a 33 volt lithium-ion
battery bank. Complete kid’s riding cars are great for large-sized
robots and they already have the drive system pre-installed. Don’t
ignore bicycles for the chains, gears, and even smaller tires for robots.
Automobile, RV, and Marine
The best items that I have found in these types of stores are the
electric window motors, electric seat motors, and electric door latch
actuators. Since cars operate from 12 VDC, most items are ready-made for robots. Car type wiring is usually stranded and far better
than solid house wiring for robots. Fuses and fuse holders, watertight
RV connectors, and trailer parts are good for robots.
Marine stores also have brass and plastic brackets and mounts
that work nicely in robots. Even used (or new) electric trolling motors
make great water-borne robot propulsion units, but be careful when
using them below a few feet as they are not made for submarines or
Other Good Sources of Robot Parts
Surplus computer stores have many neat robot parts hidden in
old printers. Stepper and DC motors, toothed belts and pulleys, shafts,
bearings, rubber rollers, and some good brackets of all types can be
found for an hour’s worth of disassembly time. Larger office machines
and copiers have even bigger robot parts such as chain and sprocket
drives, motors, toothed and smooth belts and pulleys, and all sorts of
Avoid buying many gears unless you have a good way to
position the gears within an accuracy of a thousandth of an inch.
Use timing belts, instead. Many computer places will gladly give you
old printers that they would have had to pay to haul off. Goodwill
and thrift stores are also a great source of potential robot parts.
Medical and dental machines can offer a wealth of parts, if you
are lucky enough to find some old equipment. Positionable arms to
move x-ray heads or other sensors make good robot arms. Rack and
pinion drives for exam tables are great for robots. Large syringes —
unused — make great one-way hydraulic cylinders for experimental
Security equipment is often used for sensors for robots. PIR
sensors, CCD cameras, mounting brackets and enclosures, DC and RF
wiring, and even pan and tilt mounts for TV cameras are great for
robots. Old style satellite dish or RV trailer linear actuators make