Servo - August 2015

Building Beer2D2 from Random Bits of Stuff

Once I knew I had some of the major components for the robot’s drivetrain, I had to come up with a basic design for the rest of the body. Out came the tape measure plus the paper and pencil. I measured the Heineken keg’s length and width, and guesstimated its inner volume. I measured EVA’s tread width and wheelbase includung the tire diameters, plus I weighed her. She weighed six lbs. Since I knew EVA would run for over an hour with a 2,000 mAh 9. 6 VDC NiCad battery pack, I figured the new robot should do so as well. At this point, I needed to actually buy/find some new parts.

My first stop was the Budget Robot Builder’s Emporium (Goodwill store). The first things I found in the used kitchenware section were some tin cupcake molds. I thought, "Ah, these will make excellent shoulders." Then, I had a problem. I needed a domed head for the robot. Since I had measured the top of the Heineken can and knew it was 5-1/2” in diameter, I began digging through dishes, glassware, cups, saucers, plastic kid’s toys, and nothing fit! I was almost ready to give up when I saw a stack of stainless steel mixing bowls on the bottom shelf.

I got down on my hands and knees, pulled the stack of bowls out, and right there two bowls down from the top was a stainless steel bowl that was the perfect size. I quite loudly exclaimed "YES!" Several of the women that were also shopping looked at me like I was crazy. (Little did they know, they were probably right.)

I meekly apologized for my sudden outburst and greedily grabbed my rare treasure. I grabbed a few other bowls but I didn't end up using them since none fit as well. The next thing I needed was something to mount the drivetrain into.

Astro-droids have these rectangular wheel parts and I needed three of them. Again, I searched through lots of cake pans and metal dishes by placing the servomotors and

3” tires in them, and found nothing.

So, I took the treasures I had already found, payed $4 for them, and went to Walmart to search for more ... and found nothing.

At this point, I headed toward Home Depot to get some sheet metal to make my own drivetrain enclosures. Then, I saw a K-Mart store and whipped into the parking lot. I showed the cashier my motors and wheels, and asked where their kitchen appliance section was — triggering yet another strange look.

In the kitchen section, I was very lucky to find the only three plastic butter dishes that my motors and wheels would fit in. I believe they were from the Martha Stewart collection, and cost me about $11. Finally, after that purchase, I went to Home Depot and bought three feet of 3” x 1/8” aluminum flat bar, and three feet of 1- 1/4” angle aluminum stock — plus a bunch of 1” long number six and