ALBURQUERQUE, NM--Researchers at Sandia National Laboratories have developed the world's smallest robot.

At 0.25 cubic inch and weighing less than 1 ounce, it is the smallest untethered robot ever created. Powered by three watch batteries, it rides on track wheels and consists of an 8-kilobyte ROM processor, a temperature sensor and two motors that drive the wheels. Enhancements being considered include a miniature camera, microphone, communication device and chemical microsensor.

"This could be the robot of the future," says Ed Heller, one of the project's researchers. "It may eventually be capable of performing difficult tasks that are done with much larger robots today, such as locating and disabling land mines or detecting chemical and biological weapons."

The robot could scramble through pipes or prowl around buildings looking for chemical plumes or human movement. The robot may be capable of relaying information to a manned station and communicating with other robots. It will also be able to work in swarms, like insects.

The robot, which can easily sit on a nickel, travels at a rate of 20 inches per minute.

In 1996, Sandia built an autonomous robot that measured 1 cubic inch. The researchers were able to improve on that design by using "unpackaged" electronic components in die form and by using stereolithography to make the body of the robot.