Premise: After 2 years at the MIT AI labs, Rod Brooks told me to "Think up a cool robot idea and build it." Yes, life was rough. No one at the lab had built a wall climber yet, and it seemed sufficiently cool.

Approach: The impulse was to build something resembling a natural climber, but the actuator count, complexity and mass got out of control any way I looked at it. The trick was to forget about anatomy because animals don't have rotating parts.

Result: Even with the 1989 battery mass penalty, this is the lightest wall climbing robot I have ever seen, self contained or otherwise. The design is simple but the capabilities lend themselves to many possibilities. By using 2 rotating suction feet and bending in the middle, it climbs by spinning around the planted foot, going from one foot to the next. With a 4th D.O.F. it can extend to reach for a surface normal to the one it's on- floor to wall, wall to wall, wall to ceiling. With sponge rubber sealed suction pads and diapraghm pumps it can adhere even to concrete as long as the batteries last.

Specs: Actuators: 2 high torque feet spinners, 1 bending motor, 1 extension motor, 2 vacuum pumps, 2 vacuum release valves DOF: 4 Active and 2 passive. Batteries: 6 1.25 volt high energy density Ni-Cds from Digi Key. Brain, Sensors: RJAC Motorola 6811 board. Continuous pots on feet (fluid slip rings!), pots on other active DOFs, Si membrane pressure sensors on feet, inclinometer, altimeter. Dimensions: Feet are 8" diameter, Height about 6", length is variable. Weight: 8 pounds