polycarbonate. Open the lid of the
trunk and set the polycarb into the
opening. I like to turn the trunk
upside down with the lid resting on
the ground and the main box
supported with scrap lumber for this
part. Now take your 2” x 3” piece
of lumber and cut it to fit the inside
of the lid. The polycarb should be
sandwiched between the 2 x 3s and
the inside of the lid (see Figure 3).
Run your wood screws through
the lid into the 2 x 3 around the sides.
I prefer to not run the screws through
the polycarb as I prefer to not put
any holes in it. When you drill plastics,
you create micro-cracks which over
time and impacts can grow to become
bigger cracks. If you’re anything like
me, you are very anti-crack.
(Remember kids, cracks kill).
Test the Test
Functionally, the test box is now
complete. You can throw your bot
in there, drive it around, turn the
weapon on, and everything will be
hunky dorey. At this time though, you
may notice something inherently
annoying about your test box. By
opening the lid to the complete open
position, the test box will flop onto its
back, and that’s just not cool. There
is a simple fix for this problem. Take
some of that string or lightweight
chain you have laying around and
create a leash on the outside of the
box that limits the opening of the
lid (see Figure 4). My test box
allows motion to slightly beyond 90
degrees from the closed position.
This allows the lid to stay open
without my needing to hold it open,
but it won’t tip over either.
Bling Bling. Here are a few ideas
that I’ve had that could really make
your test box the crème de la crème,
so to speak. Remember earlier when
I told you to pick up that MDF? This
is where it can come in handy. If
you’re worried about your bot
getting through the plywood side
walls, screw some MDF onto the
outside of the test box. This will add
weight, but for less than $20 a
sheet, you can’t go wrong adding it.
Another upgrade you may want
is new wheels — maybe even with
spinners. Your test box, of course,
will help you test your robots safely,
but when you go to an event, you
can use your test box to carry stuff.
Bolt your test box to a two-wheel
hand truck. Not only can you test
your bot safely in the pits (get your
frequency clip first), it will also save
you trips from bringing your stuff in
from the car. Nice. I didn’t have a
hand truck, but I did have an old
skateboard I bought at a yard sale.
It doesn’t turn great, but I can ride
my test box at the skate park.
You may also want to upgrade
the floor of your test box with the
same floor as the arena you’ll be
competing in. If the full size arena
has seams, add a seam to your test
box. Remember you’re testing, so
you want to know how your robot
will react to the conditions it will
likely face in combat.
FIGURE 5. Completed test box with bot
inside, ready to be tested.
Safety (Test) First
It has always surprised me how
much people are willing to spend on
a CNC titanium blade or custom
turned bearing mounts for the bots,
but those same spending habits don’t
translate into safety equipment. This
simple test box will last you through
many bots. The low cost of the
materials and short build time will
make it well worth the investment
the first time your bot behaves
abnormally or something catastrophic
fails, and the high speed shrapnel is
contained. Remember, the controls
are much easier to operate if you
have all your fingers. SV
C mbat Zone’s
This month, CZ is experimenting with a new feature. We all know
that creating bots is a fulfilling mental
exercise, building them is satisfying
craftsmanship, and going to events
is great for bonding with your buds.
But let’s face it — it’s about the
● by Kevin Berry
destruction! The audience doesn’t
cheer for box vs. wedge fests. It’s
the sparks, tosses, and large, flying
chunks that get that “ohhhhh!”
sound bouncing around the venue.
So, I asked a few builders to
submit their own, personal “Greatest
Hits” photos. We’ll continue this
section as photos come in.
SERVO 04.2010 35