Toggle
FIGURE 5b. Drawing of Reverse
switch; top toggle type reverse
switch, (bottom) push button
type reverse switch.
Push
Button
Read through these steps
and think about how
each component interrelates
before proceeding to cut,
bend, attach, mutilate, or
glue!
Reverse Switches
to determine what component each
switch controlled. Our results are listed
in Figure 6.
This version of the robot has several reverse switches (see Figure 5b) in
it. These are the push button type.
When they are not being pushed, the
wires are connected in one way and
when they are pushed, the wires are
connected in another way.
Tether Disassembly
The next few steps will take some
forethought
and planning.
FIGURE 6. Tether
Wire Results Chart.
Before you cut any wire,
take some time to think
about wire placement. At the
ME Lab at the University of
Washington, you will be
constantly reminded by Russ Noe to
“measure twice and cut once.” This
applies to anything you are cutting.
It’s much easier to shorten something
than to lengthen it.
Measure the placement of the
project box and decide where you will
put it. I put mine on the back and to
the left a little. The project box makes
it look like the bot has a little backpack
on (see Figure 7).
We will be mounting a 25-pin
connector on the robot. You have
a parts option of purchasing 25-pin
connectors or hacking a 25-pin cable.
Either way, the solderable side of the
Red = 9 VDC power Black = Ground
Gray
+ Red = Lights up Robot’s Eyes
Brown
Purple
+ Black +
+ Red = Arms Down
FIGURE 7. Back
of Roger Robot
showing the
project box
and the 25-pin
connector.
Purple
Brown
+ Black +
+ Red = Arms Up
Green + Black +
Orange + Red = Arms In
Orange + Black +
Green + Red = Arms Out
White
Blue
+ Black +
+ Red = Right Tracks Forward
Blue
White
+ Black +
+ Red = Right Tracks Backward
Pink
Yellow
+ Black +
+ Red = Left Tracks Forward
connector will be attached to the original wires inside the robot that lead to
the various components. The pin side
will be connected either to the original
controller or the cable coming out of
the project box that is connected to
the microcontroller. Mine is mounted
on the back and to the right a little.
However, it can be mounted anywhere
you prefer. Make sure that you choose
the location for your connector at this
step because you need to connect the
robot wires (noted in the following
steps) before you attach it to the
robot frame.
Determine where to cut the
access holes in the project box for the
cable coming from the microcontroller; keep in mind this cable needs
to reach your 25-pin connector.
If you are not sure how to decide
for yourself, you can just cut the
tether in the same way we did.
Measure from Roger Robot 12 inches
and make the cut with wire cutters.
For a cheap way to get the
connectors, check your local thrift
store for a standard parallel extension
cable. The common use is as an
extension cable for printers and other
peripherals. I have seen them priced
from $1-$3. Look for the cable that
has a female and a male connector.
Disassemble the cable for
the parts.
You may choose
to mount the 25-pin
connector in any
other location.
Decide where you
are going to mount
the connector before cutting
the tether.
Slice open the insulation
carefully for the robot side of
the tether with an Exacto™
knife (see Figure 8) or razor
blade. Be careful not to cut
or damage the insulation on
the smaller wires inside.
Remove enough of the outer
insulation so that all of the
wires can be seen. Usually
two inches is enough, if you
prefer, you can cut less.
Using wire strippers,
Yellow
Pink
+ Black +
+ Red = Left Tracks Backward
FIGURE 8. Tether being sliced
open with an Exacto™ knife.
46 SERVO 01.2007
