May 2002 Battlebots Tournament (Robots)

Ever since BattleBots came on TV, James and Alex have been bugging me to build one. Well, in partnership with Hardware Honcho Bruce Mobley, I did. Or more precisely, I did the software part. You can read about the design and construction process here.

Then it was off to sunny (hah!) San Francisco to pit our mechanical monstrosity against stiff competition.

05/18/02 - Where's our frickin' Robot?

We arrive at our hotel at 2AM and check in, only to find out to our horror that our BattleBot, sent UPS 2-DAY, has not arrived!

We are too tired to panic on the spot, so we decide to get some sleep and panic in the morning.

In the morning, online package tracking reports that, since thursday the 16th, our robot has been sitting somewhere in San Bruno, CA. This is literally walking distance from our hotel.

We call up UPS and try to put an urgent tracer on the shipment. One little problem - the tracing department won't even see our request until Monday. Since we only have until Tuesday lunchtime to get our bot checked in, this is, as they say, an matter of some small concern.

Thanks to a long conversation with a helpful supervisor at UPS, we learn the address of the local shipping depot, where the bot should have gone after San Bruno. She suggests that we might go there and ask the security guard if someone inside might help us. Worst case, even if it isn't there, we can start backtracking it.

We head off to the airport to get our rental car. They don't have the midsize we asked for, so we have to take a compact. Then we drive to the secret address we begged and grovelled for (if she hadn't given it to us, we would have hired a plane and searched for it from the air!).

When we get to the UPS depot, we are met at the gate by Security Guard Laka, to whom we explain our woes. He puts us together with a gentleman by the name of Sam Eissa. After describing the package to him, he asks us to wait while he goes and has a look.

5 minutes later he is back, and he has our bot!


Turns out that Sam is a fan of BattleBots, btw.

Now our only problem is that… the bot doesn't fit into our compact car. We end up driving the mile back to the hotel with the right rear door open and about 20% of our robot sticking out. We get dirty looks from other drivers.

05/19/02 & 05/20/02 - The Hell of BattleBot Inspection

After spending most of Saturday tweaking the bot, we get over to Treasure Island on Sunday to start final preparations for inspection. Those preparations take a wee bit longer than we expect. We run into numerous perplexing problems and transients, all of which chew up time. I'm playing with the ultrasonic mountings, and by the time I'm done, I've got 8 sensors working but mounted in about 3 different ways. The final and best solution turns out to be good old velcro, plus a strip of manilla file-folder cut to form a shroud. Oh, and did I mention that I had to cannibalize several sensors in order to get 8 that work?

Meanwhile, Bruce is tracking down several gremlins including one that energizes our chassis with 24 volts. He find that one but not before sparks fly a couple of times.

We get our first inspection, which ends quickly. The inspector doesn't like our safety restraints. We misread the rules and didn't realize we had to stop the weapons from spinning. This is pretty easy to fix but we can't get inspected until it is. And there is a 3-5 hour wait for a reinspection. Oh well. In the meantime, we turn our attention to another problem.


Yep, we're overweight according to the Official BattleBots BattleScale, the scene of much BattleBitching by the owners of obese robots.

So it's time to chop off bits of that beautiful double wedge in the center of our bot. Off comes most of the back, and holes are plasma torched into the front. Gone is the nice Evil Twins logo plate. When we're done, we read exactly 120.00 pounds, and adding a few nuts and fasteners puts us overweight.

At the end of the day, we're ready to test, and we're waiting on our final functional testing. That will be tomorrow. Hopefully we'll be able to sneak into the test box and make sure the bot works.

Here are a few picture of our bot and some other bots, some familiar, some not. The 6-legged circular walker is particularly interesting, it's the builder's Master's Thesis.

05/21/02 & 5/22/02 - Hurry Up and Wait

Evil Twins is up and running. Even though we haven't taken our final functional test yet, we're ready.

Then on Tuesday the pairings were announced. Our first fight is Thursday Night, against a new bot called Red Square.

Red Square is a Team Whyachi robot, and Team Whyachi is one of the biggest and toughest teams in the competition. It is a very simple and well engineered robot.

It's about 2 feet on each side, and only 2 1/2 inches high! It has wedge skirts around all the sides, just like BioHazard.

The weapon is very nasty. It is a curved bar of titanium about an inch thick. They winch it down flat with a strip of kevlar cloth. When it releases, the titanium bar springs up with about 4500 pounds of force. According to them, it should send us 10 feet into the air.

Currently, however, they haven't gotten it working. They are having problems with the motors and gears that wind down the spring bar. In fact, they've never tested it at all.

They plan to take it back to their hotel Wednesday night to test it, before their final technical inspection on Thursday. I have visions of headlines the next day - “Hotel mysteriously collapses; Nerds buried in debris.”

I think there is a good chance that they either won't get it working, or they will get it working but it will break itself. They have to demonstrate the weapon in a test box. With no enemy robot to flip, when that spring fires, their robot will get flipped all over the place. And the spring may break where it connects to the frame of the robot.

However, we have to assume that it will work, and if it does, it will be a very dangerous opponent. So Bruce and I have spent considerable modifying Evil Twins to deal with the threat.

The big problem is that their robot is only 2 1/2 inches high, and Evil Twins' spinner blades are about 3 1/2 inches off the ground. To deal with this, we have removed the central wedge of the bot and added four small “tongues” in the front and back of each module. This will hopefully let us scoop up Red Square and feed him into our spinner weapon. We are currently at 119.9973 pounds. The Battlebots scale reads 119.5, but 6 sheets of paper bring it up to 120.0.

We have also thought up some interesting tactical maneuvers that might be effective.

Oh well, we shall see. If we win, it will be a glorious victory against a top robot. If we lose, we'll lose in spectacular fashion.

And the winner is...

Not us. But the other bot didn't beat us, the BattleBox did. The spikes were exactly the same height as the weapon slots, and we got jammed into them and counted out. :(

...but we certainly learned some lessons.

First of all, our weapon sucked. The friction on the ring-bearing was too high, so it didn't build up enough speed. It needs to be redesigned. Not that this hurt us in our match(es) as it turned out, but we could use the weight in another way.

Secondly, both Bruce and I need to practice driving. And the only way to do that is to build some battlebox segments with steel floors and the special rubber paint. Inexperience costs you, and getting your driving experience in the actual BattleBox can be expensive.

Thirdly, we need to analyze what works and what doesn't (watching the prelims was great for that) and come up with some new design ideas. One has already occurred to us, so we are likely to run Evil Twins (mk II) and a new bot in November.

Here are some more pictures of robots (and James and Alex)