Servo - March 2012

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The Sensor Olympics

THE SCRIBBLER FROM PARALLAX.

Spring is in the air, and all of the pent-up energy from a slumbery winter is ready to be released in a flurry of competitive sporting action. Two of our favorite sporting events are on the horizon: the Kentucky Derby in May, and the Summer Olympics in July and August. The Olympics are exciting — in part — because competitors come from all over the world, from a multitude of cultural and personal backgrounds, to compete in a series of events universally agreed upon to test skill and determination in various aspects of the human condition.

Robotics competitions are similarly thrilling but instead of a clash of physical prowess, designers pit ideas against one another. The spring and summer bring with them a host of robotics competitions, like the cosmopolitan RoboGames and the frenzied FIRST Robotics Competition. One design aspect of many robots that can mean the difference between a competitive edge and the status of also-ran is sensor selection. We’ve been lucky enough to work on such a broad range of kits that we’ve seen a plethora of sensors implemented in myriad ways, and we thought putting together a little Sensor Olympics would be a fun way to go beyond the datasheets and see how some sensors compared on a practical level.

The Thin Black Line

EXCAVATING THE LINE FOLLOWING SENSORS.

The first class of sensors we wanted to compare was comprised of sensors used for line following. Line following is as classic a robotics event as track and field races at the Summer Olympics, and as time honored a tradition as sipping mint juleps at Churchill Downs every May. A perfect blend of skill and speed, line following contests reward speedy drive trains as much as they do clever programming. The timelessness of the event has led to many solutions to the basic problem of tracking a line, and throughout our years we’ve gotten a general sense of some of the common problems faced by line followers. A devious plan involving a disappearing track and a light box began to take shape, but first we had to assemble a slate of diverse competitors.