On my way home from work Friday night, I decided that I wanted to enter the 2 lb class. Quickly thinking, I stopped by Ace Hardware on my way home, and bought some 3/4" x 1/16" thick Aluminum angle stock and some hacksaw blades. Next stop was the local hobby shop, where I picked up some 3" diameter, 1" thick model aircraft landing gear made out of this nice black foam rubber. I arrived at my apartment at roughly 8:30 PM.
Once home, I fashioned a standard RC servo "disk" to the wheels, and mounted that to my (already modified) RC servos.
Next was the chassis creation, which consisted of me hacksawing, filing, and then drilling the aluminum angle stock, and rivetting it together with my pop-rivet gun and aluminum and steel pop-rivets. (Note: Rivets aren't usually good for robotic combat in the heavier weight classes, but for small, less than 10 lb, robots, it seems to work well. I used pop-rivets on 1/8" aluminum angle stock for a 38 lb robot in college, Scorpion.) The chassis measured 5" wide, 6" long.
After fastening the chassis together, I quickly fashioned L-brackets from the angle stock to mount the servos. It was at this point that I realized that I didn't have a caster for the free-wheel... great.
I found one that I used on Scorpion, but it was too
large. At this point, I decided to head to Walmart...
...but unfortunately, the one close by wasn't open 24 hours. It was now 11 PM.
Looking at the robot, and test driving it, I decided that if need be, it could run without the caster, and just rub it's chassis along the ground. I filed the edges and corners to reduce the chances of it snagging on things. I even ran it on my carpetted floors, and it didn't have a problem.
So, charge the batteries, and off to sleep.
The event "opened" at 10 AM, so I awoke at 8, quickly got ready, tossed the tools, angle stock, and even a sheet of plexiglass into the car. I headed to Walmart, in hopes of finding a small caster.
Once there, I found that their casters were too large. However, a small, ceramic drawer knob seemed perfect. I quickly bought it, tossed it into the bag of parts and tools, and headed to the event.
At the event, I drilled and rivetting on a piece of plexiglass to fasten the battery and reciever, taped them on, and drilled and mounted the knob as my free-wheel.
I went 3 for 3 against Dan Ushman's "Special K", the only other critter (and thankfully in my weight class!) to arrive.
Take a look at the 1999 Midwest Regional Critter Crunch summary for more info.