Build Your Own Combat Robot

Chapter 2: Getting Started 35
Sources of Robot Parts
There are a few hobbyist robot companies that offer parts for smaller machines;
but for builders of larger combat robots, it’s not that easy to find parts. Some companies—like
C&H Sales, Grainger, McMaster Carr, and Servo Systems—offer
many items that are ideal for robot construction, and other sources listed in the
appendixes at the end of this book offer more choices. However, most of us find
we’ve got to be creative and use local sources to complete our designs.
Before going out to find parts, think about the motions you’ll require. What
types of things move? Old washing machines have great transmissions. Electric
wheelchairs have motors and controls that have design requirements similar to the
requirements for large bots. Bicycles and motorcycles have many usable parts, especially
chains and sprockets. Power lawnmowers and rototillers have good parts, as
does furniture made with movable sections or parts. Car power seats, power windows,
electric door locks, and windshield wiper motors are good items. And don't
forget garage door openers, car jacks, car “gas springs,” cordless power tools (especially
drills), office equipment, computer printers, and even drawer slides.
The best sources are old production equipment that may have all types of
premachined metal forms, chain and gear drives, bearings, shafts, and motors.
Any type of machinery can be used in some way—farm equipment, dairy machines,
food processing machines, even items off heavy construction equipment.
Any time you see something that’s being thrown out or cheap, just think, “Can I
use this for a bot?” The famous Blendo has a shell made from industrial-sized
cooking woks.
Some people can’t afford to buy brand-new parts directly from the manufacturers.
So, surplus stores, garage sales, thrift stores, junk yards, and stuff hidden
in the basement make great bot parts. Some bots are built from parts that have
been used for other purposes, and a lot of those have won competitions. You
don’t have to have brand-new parts to make a robot, but the parts you do use
should be durable and reliable. Sometimes, however, you have to buy new parts.
When you are using recycled components, you should find out where to get replacement
parts for each component in case it breaks.
Cost Factors in Large Robot Construction
An experimental robot can cost anywhere from nothing to well over $100,000.
Mark Tilden, the creator of the BEAM (Biology Electronics Aesthetics Mechanics)
robots, can build a walking bot out of an old discarded Walkman radio in
one evening without spending a single penny. A simple microcontroller-driven
tabletop line, following robot will cost about $200, and a top competitor
BattleBot can easily exceed $20,000.