Another goal for this project was
to learn about subroutines and to get
some experience using them with the
BASIC Stamp. This became part of the
pseudocode (programming outline) for
the programs that would run Roger
Robot and give him new life.
You can do this project even if you
do not have much experience.
First things first — check your parts
and be sure you have everything you
need for the project before you begin
(see Parts List 1). Nothing is more frustrating than being at a crucial point in
your project at 2:00 am and realizing
you are missing a part and cannot go
on. You have consumed all the coffee
and pizza needed to finish the project,
but a single component keeps you
from success. Do not let this happen to
you or your crew. Be prepared by
checking your parts before you begin.
Be sure you also have all the tools
you need before you begin (see Figure
3 and Parts List 2).
It’s a good idea to have a clean
workbench or workspace when you
start a project like this. A friend of mine
has a roll of butcher paper mounted on
one end of his workbench in a dispenser. It is the width of his workbench
and whenever the paper on the work
bench gets dirty or he begins a new
project he clears the bench, pulls a new
sheet of paper the length of the bench,
and tapes it down. The clean white
paper makes it easy to find small parts.
To help you in reassembly, you may
want to grab your digital camera and
take some pictures as you build, just to
be sure you know were everything
goes.
Next, take Roger Robot out of the
package, follow the instructions to put
in his batteries, and power him up.
Become familiar with his controls.
Roger Robot has tank-style steering,
which is very desirable for robotics. A
robot can have tank steering without
having tank treads — Roger Robot
happens to come with treads. Tank
steering is when a robot has a left and
right propulsion device that can be
controlled independently or in concert.
This allows for a full range of steering
controls. All Ahead Full uses both
drives in a forward motion. Reverse is
driving them both backwards. Turn Left
can be accomplished by driving the
right forward or
the left back. For
a Spin Left the
left side drives
reverse and the
right side drives forward. This type
of steering is much easier for a
robot to use and easier for us,
as humans, to program the
robots movements. The treads are
desirable because it is easier for the
robot to navigate rugged terrain.
Become familiar with Roger
Robot’s controls. Drive him forward
and back, make him spin in place,
and operate his arms. Roger
Robot’s arms open and close for
grasping things and the arms go up
and down for picking things up and
setting them down. For simplicity,
my goal was to pick up a cup,
back up, turn around, and drive
away. The next step in future
programming could include picking
up and placing the cup in a specific
location, moving other items, etc.
Roger Robot also has “light-up” eyes.
We decided to not use this function in
this project because we wanted to save
the batteries. We will explore this in a
future project. If you like what you see
in this project and want more info,
go to www.theyshallwalk.org and
watch the pages of SERVO Magazine
for future projects.
FIGURE 3. Tools and
the robot layed out on a
clean workbench with
the remote opened up.
FIGURE 4. Remote
with cover.
Open Controller to
Trace Wires
Remove the screws that hold the
controller together. Place them into a
secure tray or zip lock bag to ensure
you have all the pieces so you can put
Roger Robot back together again. I
strongly recommend the zip lock bag
approach, especially if you have
multiple projects like I do. Mark the
bag with the name of your project
and the date you began it, as well
as the contents of the bag. Usually
in a “Disassembly Project,” I will
have a series of snack, sandwich,
and gallon size bags placed inside
of each other. The zip lock bag
approach is also very important
if you share a workbench space
with others. Boxes or trays can tip
over and the contents become
mixed or lost.
After the
controller is open, examine the wires
and where the wires are connected.
The idea is to determine what each
wire does by looking at the color that
goes to each individual switch and
what happens when that switch is in
different positions. Look at the front
cover (see Figure 4) and compare it
to the inside wire locations (see
Figure 5a).
To start with, look for the black
and red wires. These should be ground
and power, respectively, but there is no
guarantee — especially when it comes
to low-cost toys.
We discovered in our version of
Roger Robot that there was a red wire
connected to the majority of the
switches. After we verified that the red
wire was power, we traced the colored
wire connected to the
other part of the switch
FIGURE 5a.
Remote with
cover removed.
SERVO 01.2007 45
