The Mark III is a Mini Sumo robot. It’s a well engineered and complete kit, designed by a group from the Portland Area Robotics Society. It’s a great kit for a good price and can be purchased at Junun. This is also a good place for competitive priced robotics parts!
I
made some
changes. On the picture below, one wheel is removed to shown some of
them.
Blue with new battery packs
First,
I
connected the line sensors with connectors on 4-pin headers, facing
downward on
the controller board. (I did see this on the net, but
couldn’t find it. Please
tell me where if you know and I will reference it).
You
can see
the battery replacement. I did not like the combination of (four) AA
batteries
and one 9V battery, so I replaced them six rechargeable (NiMH) AA
batteries. At
first, I used the original AA battery holder and placed a second AA
holder at
the front like Dave did on his Marauder.
Since I had some problems with bad contacts on the batteries and the
higher
point-of-gravity decreased stability, the battery holders where
replaced by
three ‘battery-packs’. Each battery-pack consists
of two AA NiMH batteries,
tied together with 6 cm of heat-shrink tubing. The two packs at the
bottom are
fixed with tie-wraps through 3.5 mm holes. The top pack is fixed with
Velcro
strips. To fit them in, the controller board is raised 5mm, using nylon
rings
and longer screws. The terminal block is replaced by a kren (see top
view
below), so the batteries can be disconnected and charged with the 7.2V
charger
of our RC-car.
The
Sharp
sensors are placed on an aluminum plate, which is more stable and less
vulnerable. Pay special attention to the M3 hex nut on the bottom,
below the
sensor. This tilts the sensor slightly in perspective to the plate,
which
increases the reading of the sensor. On top, you can see the control
panel,
which is shown below.
Blue's control panel, indicating subsumtion level and sensor activity.
The
control
panel is based on the Mark III prototype board kit. This kit makes it
possible
to keep the wires and soldering at the bottom while soldering the
40-pin header
on the top side.
The
control
panel consists four leds (which I currently use to display information
from the
Sharp sensors and drive-direction), a buzzer, a TIL311 hex display
(various
functions), an extra reset button (red), three control-buttons (white)
and a
dip-switch.
The
first
opponent was the ‘red’ twin of my
‘blue’ Mark III.
You can take a look at an early
match of
red and blue.
Red and Blue
The next opponents were the robots of Erwin and the Kristof at the first meeting of the ROBOT MC group. Actually, non of the sumo robots was fully prepared for the match, but is was fun. Kristof his robot seems to be the strongest opponent and I do look forward to our next match.
2006 update
At first, blue had an oopic controller, which turned out to be too limited. I replaced it by a Microchip PIC 16f877 and use programming language JAL. The software architecture is a straight-forward subsumption implementation.
The friction of the tires is improved with Tigerbotics Traction Tires and two Sharp IS471F Proximity Detector are added to fill in the blind spot of the Sharp GP2D12 Distance Measuring Sensor between 0 and 10 cm.
Rikishi with traction
tires and proximity detectors
For the 2005 RobotMC open
championship, the robot was named rikishi and finished at the
second place. In the 2006, it took the first place at the
RobotMC open championship, in 2007 it finished second again. Links:
My
Robots