ROBOR Mini Sumo Robot

by Dale Heatherington
August 2001


ROBOR is a robot designed to compete in autonomous mini sumo contests. ROBOR is bidirectional, capable of running equally well in forward or reverse. Even his name is the same spelled backwards! ROBOR is also an acronym for "Roll Opponent Bot Off Ring".

Construction time spanned 3 months and was quite educational. I improved my metal working skills, learned about sonar and programming subsumption architecture.

Click here to see photos of the July 2001 mini sumo contest at the AHRC meeting. You may download a zip file with schematics and source code by clicking here . This information is not intended as instructions to duplicate Robor. In fact, it may be incomplete or erroneous. Use it at your own risk.

Data Sheet
Size 9.8cm(W) x 9.4cm(L) x 11.5cm(H)
Weight 496 grams
CPU Two PIC16F876-20/SP
8K ROM 368 Byte RAM
Assembler and C
Motors Two Escap 280 RPM 12 v gear motors
Motor driver
Wheels Four 1 inch diameter slot car tires
Drive system 4WD with timing belts
Speed 22 cm/sec
Pushing force 360 grams (wheels spinning)
Power Single lithium 9 volt battery
Current 100 mA crusing, 290 mA pushing
Sensors Four reflective IR sensors for edge detection
Custom 4 channel sonar to locate opponents
Tilt sensor
Fwd/Rev motion sensor (are we being pushed?)
Telemetry Linx TXM-418-RM (9600 baud 418 MHZ)

Robor - in the nude

Front view, covers removed.

Sonar sensor board visible. ROBORs sonar measures both distance and amplitude in four directions to determine the opponents location. The sonar code is written in assembler.


Rear view, covers removed

Rear view.

Main controller board visible. Controller code is written in C. Small green board in upper left corner is a 418 mhz 9600 baud telemetry transmitter. White object between wheels is the 9 volt battery.


Bottom view

Bottom view.

The protruding brass shaft is the tilt and movement sensor. In/out movement indicates tilt, rotation indicates direction of movement.


Tilt sensor

Closeup of the top end of the tilt/directon sensor rod.

When rod drops down the black band is in front of the IR reflective sensor indicating tilt. Rod rotation brings the white or black half in front of the top IR sensor indicating forward or reverse motion. When software detects tilt or motion reversed from desired it activates an escape algorithm.


Robor vs Movit

ROBOR is tested against the larger and heavier MOVIT OWI-9647 kit robot. ROBOR always wins.