of screws that held the front panels on, and eventually the front panels were lost (Figure 5). However, the bots battled on. I observed that every time a screw popped off, the crowd would cheer. When a front panel was lost, they went wild. It was pandemonium. I would tape the front panels in place just so they could be torn off again. Nothing is cooler than a bot dragging around part of its ripped off chassis.
One thing I took away from this experience is the idea of designing a set of bots that could rip each other apart. The PROCS design looks like a good place to start, but in this application it’s really not. Because of the actuators and microcontroller control, each cost over $2,000 to build. I also thought they held up a little too well. I went back to the drawing board.
What I came up with is what I call PBOD. This stands for Plastic Bot of Destruction. The opening photo shows a prototype that I have been working on, but I’m sure we can make improvements. Let’s take a look at how this series will unfold.
The prototype shown at the beginning was a proof of concept. Could I design and build a small inexpensive bot that could be used in a radio controlled battle scenario? The prototype showed it could be done. All of the parts except for the electronics, hardware, and tires were completely 3D printed. Although it’s a little sturdier than what I eventually want, it helped me come up with a set of goals for this project.
1. The PBOD has to be printed in ABS or PLA. If machined, it has to be expanded PVC.
2. The frame cannot be made as a unibody frame. It must be constructed with a base, with separate sides and top.
3. The parts can be 3D printed, laser cut, or machined with a CNC mill.
4. It must use a motor controller that is capable of mixing the RC signals to control a differential drive with two channels.
5. A four-channel radio should be able to control the robot and weapons.
6. No projectile weaponry. No fire or explosives. Flippers, spinners, or hammers are okay.
7. The wheels must fall into the same rules as the frame. With the exception of the tread material, they can be foam rubber, rubber, or some other soft material to allow for traction.
These goals are only a starting point; once the weaponry is complete and the PBOD has a few battles under its belt, we can make changes.
You can see the prototype in action at www.youtube.com/watch?v=pK57Tw3dL3U.
Now that I have a working prototype and a set of goals, I have chosen the gear I will use to construct the PBOD.
I decided on the Sabertooth dual 12 amp motor driver from Dimension Engineering (Figure 6). While 12 amps is overkill for the bot we will be building in this series, it allows for a great deal of expansion in the future.