From 1997 to 2004, I competed around the world in a number of different robot categories, primarily sumo robots. I also worked a lot of shows (judges are always in demand) while teaching robotics at San Francisco State University. One thing I noticed in that time was not only the variety of robots out there, but also the variety of skills needed to build a robot.
And so I started RoboGames. The goal was to expose an audience at large to all the different sports (they’d come to watch combat, but stay for the soccer), and to cross-pollinate the contestants so that they’d become more familiar with other disciplines and possibilities.
Let’s break down the categories of robot sports:
A. HUMANOIDS: The dream of all robot thinkers. They’re usually only about 16 inches tall, but modern humanoid robots can walk, run, do cartwheels, backflips, and even play soccer and basketball.
B. SUMO: The oldest of robot sports, going back over 30 years. Basically, Rubik’s Cube-sized robots that can think for themselves and autonomously find their opponent and push it out of the ring.
C. COMBAT: Just like NASCAR, it’s exciting, big, and there are lots of crashes and explosions. While 100kg (220lbs) is the size of choice for the audience, there are six different weight classes as small as 150g (5.3oz) (see “Know Your Combat Robots!” on page 26).
D. SOCCER: Sometimes played with humanoids, sometimes with wheeled bots, this is the hardest of the robot sports. You have to be able to program the robot to do all sorts of moves and work with between 3 and 11 robots per team.
E. AUTONOMOUS CARS: Commercial autonomous cars still don’t perform perfectly, and so we have autonomous robo-cars: line followers, NatCar (really fast line followers), and RoboMagellan, which is fully GPS driven.
F. HOCKEY: Three remote controlled robots to a side play hockey using a standard street puck.
G. ART BOTS: Robots don’t have to be limited to roles of speed and strength. What about beauty? We celebrate robots that make cocktails, paint, play musical instruments, or just look and act cool!
H. OTHERS: If you can think it up, there’s an event for it. Robots that balance like Segways, robots that can put out fires, solar robots, task-oriented robots … For a full list of events and rules, check out robogames.net/events.
At RoboGames, there are 54 categories in total. Many of the robots have a lot in common:
I. MOTORS: Combat and sumo robots can get away with two motors or servos, while humanoid robots have from 18–30 of them. Motors range in cost from $1–$2,000 and servos are about
$5–$200, depending on quality and abilities.
J. ELECTRONIC SPEED CONTROLLERS (ESCs): These control the motors. Do you want to go fast or slow? The ESC determines that. ESCs cost from $30 on the tiny robot side all the way up to $1,000 for large-scale robots.
K. BRAIN: The computer that runs everything. If you’ve played with an Arduino, you’re already started! Humanoid robot brains are often specialized controllers that position each servo like a human muscle or joint, as well as take all the input from the sensors to control how the robot reacts to its environment.
L. BODY: Here’s where things get crazy. I’ve seen robots built from literal scrap metal to custom CNC’d titanium shells costing $20,000. Obviously if you’re competing in large-scale combat you want something that’s made of metal, while a 500g sumo robot is best made from plastic.
RECHARGEABLE BATTERIES: Robot batteries are usually lithium-based and come in either a C-cell shape or custom flatpacks. Good batteries are both expensive and dangerous (look up “lithium battery fires” on YouTube). You can get quality rechargeable packs from $50 on up, depending on how big your robot is. They’re measured in both amp-hour charge (how long they’ll last) as well as how fast they can be discharged. Beware: Draining a lithium battery too quickly is how fires start.
BATTERY CHARGER: Chargers are usually sold separately from their power supplies, so this is a two-fold purchase. Never buy a cheap charger — it’ll ruin your batteries and you’ll be out a lot
of money.
WHERE TO BEGIN?
If you’ve never built a robot before, regardless of what you’re into, my suggestion is to start with a kit. Why? Because you probably don’t have all the tools needed to build something right away, and mistakes in robotics can be expensive.
Category-wise, there are three directions I recommend you take as a starter:
• COMBAT: Start small. I suggest beginning with a 3lb robot. You can get a kit for around $150. Add on two battery packs, a battery charger, and a transmitter and you’re at about $400.
• SUMO: You can get a decent 500g (2lb) mini-sumo kit for around $100. If you want to learn to program robots around sensors, this is the best way to start. You’ll learn about controlling speed, vision sensors, and programming for a real environment.
• HUMANOID: Because of the number of servos involved, humanoids start at around $1,000 and go up from there.
• HOCKEY: OK, a fourth option. If you’re hell-bent on building your own robots, I’d suggest starting with a trio of hockey robots. Use battery packs and gearmotors from cheap drills, cut a frame from polycarbonate with a handsaw, pop in some scooter wheels, and then throw in an ESC and transmitter, and you’ve got yourself a hockey team.
The final factor in competing isn’t so much what you build as where you live. Like many sports, you want to play against someone! To really compete in robot sports, you need to live near a bunch of people who also want to compete, and you need an arena.
Either that or travel to a robot event. There are more of them popping up all over the world all the time, so really it’s just a matter of Googling your city and “robot events” and working from there.
The best way to start is to just sign up for an event to give yourself a deadline. This will help to ensure that you don’t leave your robot unfinished. If you’re looking to compete, a good place to start is here which lists events all over the world.
Later this year, RoboGames will be returning and featuring all of the above mentioned events. You can find more information here at , including rules, photos, and help to get you started. Go out there and have fun!
THE FUTURE
Since I started in robot sports, I’ve always felt that robots were the future of sports. If you compare robots to the UFC, for example, robots heal much faster than humans. So while a human UFC fighter might only have 2–3 fights per year, robots could support weekly events, just like the NFL does — and even then, football players get injured all the time.
So a better comparison is NASCAR, but with the obvious difference that the robots are trying to kill each other, while in NASCAR they’re just trying to outrun each other. But it’s the crashes, fires, and explosions that make the highlight reel — which is what robot sports are all about! 
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