Technical question - Mark J. here: Lots of different fastening techniques go into a robot depending on what has to be fastened and the stresses involved. We usually hold down our radio receiver with Velcro, 'cause it's easy to remove and replace and the reciever weighs very little -- but I wouldn't use Velcro to hold the motors in place!

Hot glue could be used to hold small wires out of the way, or for other low-stress applications. Some antweight 'bots use types of glue to bond their chassis together -- rubberized cyanoacrylate or epoxy plus a wrapping of high-strength thread works well for graphite rods. I wouldn't care to try it in larger robots.

A: I try to keep my 'bots simple and not try too much new on a new design. I also learn from the designs of other builders.

How much money does it take? All you have.

A: There are lots of books in your local library that can help you design and build your own robot -- no need to copy mine! See the links in the last post on this page, too.

A: We've built several successful Antweight competitors out of R/C toys. Our current Beetleweight is based on an RC toy (with quite a few modifications) and it has done very well. A Featherweight? Probably not.

A: I count six competition robots in all:

• Rat Amok - antweight combat - retired, but operational;
• Mini Maxbot - antweight combat - operational;
• Mini Maxbot 2 - Antbotica competitor - operational;
• Zpatula - beetleweight combat - operational;
• Run Amok/Run Away - Heavyweight combat - retired, but operational;
• The Gap - Robot Wars heavyweight - operational.

A: All of my 'bots are built for combat or head-to-head competition. No humanoid 'bots -- but I think that 'bots like Robo-One are really cool!

A: Mark J. here: Technical question time!

A 4-bar mechanism is a simple arrangement of four mechanical links (like rods or beams) with pivot connectors on each end linking them together into a roughly rectangular shape. By careful selection of the relative lengths of the links used, you can create complex movement arcs and gain torque or speed without gear reduction. An example of a 4-bar mechanism can be seen at www.me.dal.ca/~dp_03_5/designs.htm.

Robots sometimes use 4-bar mechanisms to control and position lifter arms efficiently and allow them to scoop in a sweeping upward and outward arc rather than a simple single-pivot backward rotation. Aaron's beetleweight uses a 4-bar mechanism in its electric lifter.

A: Mini Max Bot started out as an R/C skateboard toy. It's whole structure is some kind of plastic. Thin slices of automotive radiator hose are used as tires.

A: Yep, Zpatula has a lifter with a 4-bar linkage. Zpatula's drive motors are 6 volt Mabuchi 130s -- a Mabuchi 180 powers the lifter. We live in Oregon.

Q: Don't you think 130s are a bit small for a beetle? I use 300s in my ant. (Alex U., Pittsburgh, PA)

A: Mark J. here: Let me take this one, Aaron.

The maximum amount of drive power you can effectively use in a 'bot is limited by the weight on the drive wheels and the grip of the tires. Additional torque just spins your wheels. You can 'gear up' to trade torque for speed -- but how much speed can you effectively use in a 5 or 6 foot square ant/beetle arena?

Zpatula is 6-wheel drive and can easily spin it's wheels to avoid motor-destroying stall. The twin, mildly over-volted 130 motors give good controllable speed and deliver about 4 watts of power per pound of robot -- just about the same ratio as our Robotica winning heavyweight 'Run Amok'.

People often believe that Team Run Amok's 'bots are underpowered, but we have championships from half the events we've entered. Not many teams can match that record.

A: My dad get parts from a lot of places, and we make some of our own. Places you might try:

Team Delta
Microbotparts.com
Sozbots
Robot Marketplace

A: Sure! I play soccer and streetball, I have a weekly Yu-Gi-Oh tournament, and I'm a counselor-in-training at the YMCA camp.

A: I won my first competition driving my own robot last month at daVinci Days. My beetleweight "Zpatula" fought in a round-robin tournament against all the other robots. I won all but one fight and took the championship.

A: Being at a robot competition is great! Competing is really intense. I like out driving and outlasting the other robots, but I don't really like to break stuff. I want to leave 'em pretty, but beaten.

A: By the time we're thru with a robot it's either a champion or a pile of scrap. We don't sell our champions, and nobody would want the pile of scrap.

A: We made lots of friends at Robotica and I don't want to pick out just one 'bot as my favorite. I really liked JuggerBot, Jawbreaker, and Kritical Mass. My dad says he liked Pandora for the cool way the builder used the parts he had available.

A: The only combat robot kit I know of is an antweight, and it isn't 'cheap'. Scroll down a little and read about 'converting an R/C toy' -- that's more fun than a kit and you'll learn more.

Also, take a look at this page on How to Convert a BattleBots Toy into an antweight combat 'bot.

A: You can keep an eye on EBay. Some builders will sell their old 'bots there to get money to build a new 'bot. It's more fun to build your own!

A: Yep. See 'DaVinci Days' antweight tournament.

A: R/C toys are great! I have a few R/C toys and I play with them a lot. I'd like to see a picture of your Immortal Wheel -- cool name. I converted one of my toys into a beetleweight combat robot for a competition this summer (picture at right). It did great!

A: There are lots of good books on how to build a combat robot, but it's too big a topic for me to talk about here. Check my dad's web page for some of the books, and check with your local library.

You can also get a quick lesson in robot building at coolrobots.com. Click on "Build a Robot".

A: Wow -- that's really light! In the U.S. we get a full pound for antweights - 454 grams.

I live near some places that build parts for airplanes and I can get scrap pieces of thin titanium that are great for robots. Titanium is light and very tough, but it's usually expensive and hard to find.

You might want to consider thin carbon composite material instead of metal. Robotcombat.com marketplace sells small sheets of it. It's very stiff and strong.

Some types of plastic make good armor for light robots, too. Polypropylene is used for kitchen storage containers and is very thin, light, and tough.

A: It's a little like making a statue of an elephant: you start with a big chunk of rock and carve away everything that doesn't look like an elephant.

Seriously -- there are all types of R/C toys. Some have steerable front wheels and some steer by making the wheels on one side turn the opposite direction from the other side. That later type is more maneuverable and might make a better robot, but either type will work. Just start taking off things that don't look like they belong on a robot -- the body, bumpers, wings, roll bars, whatever. Get it stripped down.

The next step is to weigh the stripped-down toy to see how much armor and weapon weight you can add without going over the maximum weight for the class of robot you want. Toys make good 1-pound and 3-pound weight class robots, and larger ones can fight in the 12-pound class. Bolt on your armor to protect the wheels and other delicate stuff. Plastic that won't crack is good, or fairly thin metal. Bolt on a wedge or a couple of spikes and you're a roboteer! You'll learn a lot from the things that go wrong with your first 'bot, and you'll have fun. Be careful with anything sharp, and don't attack your cat/dog/hamster!

A: Mini Amok weighs in at about 2kg, so technically it would qualify. It would take a little work to 'harden' Mini Amok up to battle standards. I think I'd rather keep it as a pit toy.

I'm building a new 'beetleweight' robot named 'Zpatula'. Six wheel drive with an electric lifter (picture posted above - scroll up). At 3 pounds, it'll still be too light to be competitive in the 12 kilo class.

We also have a 12 pound class robot named 'Nasty Glass of Water'. It's built to pick up other robots and use them as weapons! My dad told me once why it has that funny name, but I don't remember. It doesn't show up on our website because it keeps changing all the time. But it could pick up another 'bot and still be too light to be competitive. We like heavyweights!

A: Try visiting www.coolrobots.com for tips on big robots. For ideas on smaller (antweight) robots, try www.sozbots.com.