Going Further With
The Beginner Bot
Yesterday’s robots can teach us a lot
about today’s robots. That’s because
old school bots used simpler ways to
control them. It was easier to
understand what was happening,
thanks to their reliance on simple
circuits. You could see how the wires
connected from one point to the next,
and visualize how the juice from a
battery turned on this component, or
switched off another.
There’s no need to stock up on tubes and giant relays ... we don’t need to go that far back in history! If you’d
like to step into the world of smart robotics, however, a
great way is to learn how to build a no-frills, no-brain
mechanical pet that uses basic electronic parts to move
around the floor.
What’s even better is the parts for your bot can be repurposed when you’re ready to move to the next step.
by Gordon McComb
That’s the idea of the Beginner Bot, introduced last month.
In Part 1, we discussed how to construct the Beginner Bot
using common materials like plywood or sheet plastic. We
also discovered how to drive and steer our bot by using a
pair of mechanical switches.
This time, we’ll go to the next level. We’ll replace the
manual switch control with fully automatic — yet simple —
electronic function. Our robot will react to light, coming
toward any bright light source.
Using just a flashlight, you’ll be able to lead your robot
around a darkened room. (Yeah, I know I was going to
demonstrate tactile feedback this time around, but I’m
going to save that for a future installment.) Figure 1 shows
the completed Phase 2 Beginner Bot — all ready to be
guided by nothing more than photons.
Remember that the techniques you’ll learn here — and
even the components you’ll use — will be applied in
upcoming episodes of the Beginner Bot series.
Mechanical switches help
demonstrate how to control the
motors of a robot. As you
discovered in Part 1, motor direction
is controlled by alternating the
polarity of the current applied to
the motor’s terminals. A double-pole, double-throw (DPDT) switch is
a great demonstrator of robot
A manually controlled robot is
nothing more than a fancy toy; it’s
not a true robot until it can run on
its own. Through electronic control,
you can replace the switches with
FIGURE 1. Completed Phase 2
Beginner Bot with snail-like "eyes"
for following bright lights.
36 SERVO 09.2011