Dale's Homemade Robots
Delta Force
Delta Force
Delta Force Mini Sumo Robot
by Dale Heatherington
Sept 2001

Delta Force is the second robot I designed to compete in autonomous mini sumo contests. I originally intended to build a simple wedge bot target drone to aid in developing defense strategies for my other sumo bot ROBOR. It worked much better than I thought. It beats ROBOR in every match except ones contrived to put Delta Force at a severe disadvantage.

Delta force took about three weeks to build. I reused most of the programming code from ROBOR. If you want to see schematics and source code click here to download a zip file. The schematics are large gif images suitable for printing. Click here to see a time lapse sequence of Delta Force fighting ROBOR.

Feb. 15 2003: Delta Force wins AHRC 2003 Robot Rally Mini Sumo contest for the second time and remains undefeated. This year I replaced the 2 AAA batteries with a 9 volt battery. This increased the motor voltage from 12 to 18. Delta force is almost 50% faster than it was last year and had no trouble defeating it's opponents.
Feb. 9 2002: Delta Force wins AHRC 2002 Robot Rally Mini Sumo contest and remains undefeated. Click here for pictures. Delta Force has some additional features not present when this page was originally published. I added 2 AAA batteries to increase the power supply to 12 volts and added a drop-down false white line on the rear to help prevent rear end attacks. There is also a rubber brake pad on the bottom rear to prevent being pushed backward when the front end is lifted.

Data Sheet
Size9.9cm(W) x 9.9cm(L) x 6.8cm(H)
Weight498 grams
CPU PIC16F877-20/SP with 16 MHZ Crystal
8K ROM 368 Byte RAM
MotorsTwo Lego 350 RPM 9 volt gear motors
Motor driver
Speed ControlSoftware generated Pulse Rate Modulaton with Back-EMF feedback. Pulse width is constant.
TiresTwo 30.4 mm diameter Lego tires
WheelsCustom made steel
Drive systemDirect drive from Lego motor shaft
Speed36 cm/sec
Pushing force450 grams (wheels spinning)
PowerTwo Alkaline 9 volt batterys
Motor Current60mA crusing, 400 mA pushing
SensorsTwo reflective IR sensors for edge detection
Custom two channel active IR to locate opponents
Telemetry Connector for external transmitter
Linx TXM-418-RM (9600 baud 418 MHZ)

Delta Force bottom view
Bottom view.

Rear disassembled view
Rear view.
Active IR sensor board visible.

Side disassembled view
Side view, disassembled.

Active IR sensor board
Closeup of the active IR sensor board.
Small black device in center is an IR pin photo diode.
Two pairs of high power IR LEDs are on the left and right sides.
They are pulsed at 1/2 amp, 500 times per second.

Controller board
Controller board.

Custom steel wheel, Lego tire, stock Lego wheel
Using steel for the wheel material added 48 grams above the weight using stock lego wheels.