PART 3 — Adding a Little
Speech, and Extras
by Robert Doerr
Over the last couple months, I’ve been using a lot of
leftover parts to revive an early Androbot BOB prototype.
He was missing all of his brains and had been sitting for
years as an empty shell. Although I would have preferred to
find the original electronics, I decided that I should at least
use some extra parts from past projects to get BOB rolling again.
All of the new electronics just plug in and bolt on
so that no alterations are done to the original shell.
The February ‘08 issue covered how a Handy Board was
upgraded to act as the main controller for the robot and
how to make it drive larger motors. In March ‘08, a method
of multiplexing the sonar transducers was shown so that all
five sonar sensors in the head could be used. The original
encoders for the main drive motors were also wired up to
get some feedback from them.
Many issues came up and were resolved along the way,
which I hope will help with your own projects. Some of the
examples shown here were selected because of parts I
already had on hand and others just to show a different
method of doing something. When doing prototypes,
everything is fair game. Once you get it together, you may
change it around a few times before you get it the way you
want. This article builds upon the previous ones and will
cover adding a co-processor to control BOB’s head assembly
and some lights on the body. We’ll also cover adding a
SpeakJet chip so BOB can talk and a method of sharing a
single serial line so that the Handy Board can talk to either
the co-processor or the SpeakJet.
Adding a Little Helper
Instead of the Handy Board controller keeping track of
every detail and operating every peripheral device itself,
some of the tasks can be offloaded to another processor.
For the BOB project, it seemed like a good idea to let
another microcontroller handle some tasks like the lights
on the body and the closed loop control of BOB’s head.
For this, I chose to use an SX48 protoboard from
Parallax as it is inexpensive, easy to program, and has plenty
The SX48 co-processor board.
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