Bugdozer Miniature Autonomous Sumo Robot

Bugdozer is the first of many mini sumo bots that I’ve built over the years. My current champion is Number Two, but Bugdozer will always have a special place in my heart.

In 2000, to push myself into really learning robotics, I made a personal goal of competing in Central Illinois Robotics Club’s (CIRC) Second Annual Robotics Competition.

First Place Mini-Sumo Class Sumo Robot Competition 2000 Sponsored by the Central Illinois Robotics Club

Bugdozer won first place!

For the couple of months leading up to the contest, I prototyped and built an entry in the smallest class of Sumo bots. To learn more about Robot Sumo contests, see the Illustrated Guide to American Robot Sumo.


  1. Autonomous (no remote control)
  2. Mass of 500 grams or less (17.637 avoirdupois ounces)
  3. Width of 10 centimeters or less (3.937 inches)
  4. Depth of 10 centimeters or less (3.937 inches)
  5. Delays start of movement for 5 seconds at beginning of a round

Preferred Standards:

  1. Capable of consistently beating a 1/2 pound 10 cm by 10 cm block of wood
  2. Never falls out of the ring on its own
  3. Actively seeks opponent
  4. Avoids getting hit on the side
  5. Motors rated sufficiently to win reasonable head-to-head pushing match
No bug is too small for Bugdozer!

No bug is too small for Bugdozer!

I felt as if I could finish and enter even a single decent robot with these qualifications and standards that I would be satisfied with my progress as a robot hobbyist. In laboratory test trials, on Saturday, October 7, 2000, 7:45 PM CDT, Bugdozer demonstrated it met and exceeded these expectations.

Bugdozer front view Bugdozer side view Bugdozer rear view
Bugdozer overhead view Bugdozer underneath view

Views of Bugdozer’s body

1. Autonomous

Bugdozer’s motherboard

An MC68HC908GP32 running at 8 MHz. Several kilobytes of hand-coded assembly and data attack tables. Plenty of support chips for I/O, voltage regulation, motor H-bridge driving, and 38-kHz carrier wave generation.

Click here for more about Bugdozer’s motherboard...

2. Mass

Approximately 493 grams.

3. Width

Bugdozer’s width and a milk-chocolate M&M’s candy for size reference

Bugdozer’s width and a milk-chocolate M&M’s candy for size reference

Just barely under 10 centimeters at the tires.

Around 9.5 centimeters at the front scoop.

4. Depth

Bugdozer’s depth

Bugdozer’s depth

Almost exactly 10 centimeters from scoop to rear of tire. (The photograph angle gives the illusion of its behind exceeding 10 cm)

5. Delay Start

Bugdozer’s start button

Bugdozer’s start button

The red button on the motherboard starts the five-second countdown to combat. The front sensor lights flash on and off every second to show the robot is under starter’s orders.

6. “Brick” Test

The vicious wooden monster

The vicious wooden monster

The original test was to beat a 1/2-pound block of wood. Well, look out for this nasty opponent who tips the scales at over a pound. That’s a lot of wood!

Click here for videos of Bugdozer in test runs...

7. Line Sensors

Red ultra-bright emitters and near-red phototransistors for Sumo line border detection

Red ultra-bright emitters and near-red phototransistors for Sumo line border detection

Gloss bright white lines trim the edge of the Sumo ring. To insure Bugdozer doesn’t accidentally stray out of bounds, four ultra-bright red LEDs and five near-red phototransistors detect lines in front of and behind the robot.

Click here for close ups of the line detectors...

9. Avoids Being Hit on the Side

Side painted black to avoid being seen

Side painted black to avoid being seen

Three design features are implemented to avoid being hit on the side:

  1. Decrease side detection by painting the sides black
  2. Retain reflective surface in front to attract opponents targeting systems to the front
  3. Detect opponent first and almost always face and center opponent

Click here to see details of the body design...

10. LCD Panel

Text LCD panel

Text LCD panel

For debugging and testing, Bugdozer has an LCD panel. A lot of cool data is collected and displayed. An onboard panel is much easier to use than a wired or infrared computer connection.

Because it would lead to qualification violations, the LCD panel isn’t used during competitions. Specifically, the width of the panel (as it fits onto the connector on the robot’s motherboard) hangs beyond the 10 centimeter limit. Also the panel adds considerable weight, about 60 grams (2.1 ounces). The weight is placed in the back, which is a bad spot as it tends to make the robot more likely to tip backwards.

Click here for screen shots of Bugdozer’s LCD...

Next, let’s see how Bugdozer’s aluminum sheet body was made...