Servo - September 2011

www.servomagazine.com/index.php?/magazine/article/september2011_TwinTweaks

Getting Serial

which specialized as mini Sumo robots. The Mark I was originally developed by Marvin Green of the Portland Area Robotics Society (PARTS). The Mark I was meant to serve as an easy-to-use robotics kit that aspiring roboticists could use in the first annual PARTS MiniSumo competition held back in 2000. Improvements were made and the Mark II was born for the second annual competition in 2001. The Mark II included upgrades like infrared sensors (the classic Sharp GP2D12 sensors) to detect the opposing robot. The Mark II eventually evolved into the current Mark III, with the main goals of making the robot general-purpose and expandable.

The CPU for the Mark III is a PIC16F877 from Microchip. The Mark III is OOPic compatible and, in addition to this programming flexibility, it is also amenable to a number of physical embellishments called mezzanine boards. The mezzanine boards can mount on top of the controller board and delightfully expand the capabilities of the kit. The mezzanine boards range from a breadboard-like prototyping platform to a sensor board equipped with servo headers and a buzzer, among other bells and whistles.

On the mechanical side, the Mark III is driven by two GWS servo motors, and it rides atop two plastic injection molded wheels. The Mark III retains the compact frame of its mini Sumo pedigree — complete with the front wedge and low ground clearance.

A Robot For All Seasons

As much as anything else, this is a tale about the evolution of a robot. We admire the Mark III for being the product of an independent robotics group, and we think the real challenge of a product like the Mark III is to keep up in a market saturated by the next version of whatever you just bought, and where everything moves on Apple time (which must be the polar opposite of geologic time). Our experience with the Mark III began around 2007, when our dad ordered the kit as a fun project to work with in his spare time, and in particular as a way to begin working with OOPic.

For starters, the Mark III board must be soldered together from scratch. While some might find this endeavor tedious, we always found the step-by-step soldering of circuits to be a languidly pleasant affair and a great way to become acquainted with the kit. The Mark III PCB is meticulously labeled, and putting everything in its proper place is a very straightforward task.