1-hour Antweights (Robots)

I figured it would be a good idea to build a couple of 1 pound “antweight” robots for James and Alex to play with. But with all the other robot work to do before Battle on the Beach, I didn't have much time. Fortunately, at Xmas I had gotten them a couple of Battle Bloks RC lego-compatible robot kits ($30 at Toys-R-US), which are just perfect for making simple antweights.

These are great little robot modules that can be set to work on one of two frequencies, 27.145 or 27.045 mhz. The little bubble on the top has caps that click into it that both turn on the robot and select the frequency.

Remove 10 screws (2 hidden in the battery compartment) and you've got a basic drive train. If you're doing extensive modifications, you probably want to detach the antenna wire and mount it somewhere else.

Step one is to remove the little grey nubbins on the frequency and power switches. The plastic cap isn't robust enough for robot combat, but there's an easy fix. Note the crystals say 26.590 and 26.690 mhz, contradicting the documentation. No idea which frequency is correct!

Next, tap the two holes on the case using a 6-32 tap. This lets you use some 6-32 screws (you'll need some 1/2“ ones) as power and frequency switches, just like the team whyachi switches, but a lot cheaper (grin)!

Decide on how you're going to mount your weapon. The lego connectors are spaced 8mm center to center, and a 7/64” drill goes down into them nicely (and can be tapped with the 6-32 tap). Even the regular connectors have a little dimple that will center the drill. I happened to have some hinges that had 24mm centers on them, so I used them as mounts. I reinforced the mount with a little epoxy.

The secret to getting the weight of the robot under 1 pound is in the batteries. Non-rechargeable lithium batteries weigh almost nothing, much less than any other option. A bit expensive, but they last a long time, a set ought to easily last for several competitions.

And here we see the finished products. Maybe not the most technically advanced antweights, but I think the kids will have fun with them.