Expendable
Sumo robot competition was becoming too serious, so Expendable was
created for the
Summer 2003 NEIRG event.
Expendable started with a Parallax Boe-Bot kit. Two Hi-Tec HS-925MG servos are driven by external FET H bridges and a Pololu Dual Serial Motor Controller. A carbon fiber “scoop” replaces the original white plastic ball of the Boe-Bot. Eight AA Nickel-Metal Hydride batteries and molded silicone tires complete the drive train. Yes, the Boe-Bot is running backwards for this application.
An add-on perforated board holds the five IR emitters and detectors for
opponent detection. The perforated board is mounted on Lego’s attached
to the BOE. The sonar mounted above the chassis is for jamming the
opponent’s sonar. Four black audio transducers play “Mary Had a Little
Lamb” before every bout. An alarm sounds whenever Expendable locked
onto an opponent. Control is provided by a
BS2SX, of course.
Red foam rubber lips are intended to strike fear into Expendable’s
opponents. The lips turned out to be Expendable’s most effective
weapon. Could it be that most autonomous sumo robots are afraid of a
little intimacy? The red feather boa seemed like an appropriate
addition and the Daisies appear tacky enough.
Expendable weighs 1 pound 7.4 ounces and can push 3 pounds 11 ounces.
Its top forward speed is 27.4 inches per second.
The sonar jammers
proved too much for everyone except
Shunji with its IR
sensors. A third place finish behind Shunji and
Sticky
was fortunate considering all the opposition was four times heavier.