Robots need information about the world around them, or they just
stumble about looking stupid. Just like us humans, a robot uses senses
to know when it’s run into something; when it’s light or dark; when it’s
too hot or too cold; when it’s about to fall over; or when it’s found the
way to the cheese at the center of a maze.
Senses require sensors. In the practice of robotics, the basic senses make do with the most basic of sensors: mechanical switches for detecting contact with objects, and photosensitive resistors and
transistors for detecting the presence (or absence) of light.
A robot can perform a remarkable amount of work with
just the sense of touch and the gift of simple sight.
In this month’s installment, you’ll learn about
interfacing switches and photosensors to the Arduino,
along with how to use the information these sensors
provide to interactively command a robot’s motors. These
are the fundamental building blocks of most any
autonomous robot you build. Once you learn how to use
these sensors to do your bidding, you can apply them in
dozens of ways, for all kinds of robotic chores.
What We’ve Covered So Far
This article builds upon previous installments in this
series, which is all about the construction and use of the
ArdBot (see Figure 1) — an inexpensive two-wheeled
differentially-steered robot based on the popular Arduino
Uno and compatible microcontrollers. If you’d like to follow
along, be sure to check out the previous three episodes, so
you’re familiar with the plot and characters.
Part 1 introduced the ArdBot project, the Arduino, and
basic programming fundamentals of this powerful
Part 2 detailed the construction of the ArdBot, using
common materials such as plastic or aircraft grade plywood.
Part 3 covered the Arduino in more depth, and
examined the ins and outs of programming R/C servo
motors with the Arduino.
FIGURE 1. The
ArdBot robot uses an
and two R/C servo motors.
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