ISAAC by Don Newman

ISAAC (Intelligent Subsumption Architecture Artificial Creature)
It is a robot based around the subsumption architecture principles of
layered behaviours and runs on a 68HC11 microcontroller.  The
behaviours currently programmed are explore, runaway, and avoid
obstacles.  It has four sensors; front, back and two sides. Also
incorporated is a two motor drive base.  Power is supplied via two
nine volts for the sensors and microcontroller and four C-cell
batteries for the motors.

The approximate cost of ISAAC was around $300 canadian and a total of
100 to 150 hours time constructing it.  Future upgrades for ISAAC
include more advanced behaviours, more sensors, speach, and eventually
a solar conversion to reduce battery consumption.