Micro-robots can spin on a coin

Researchers in the US have built an autonomous, battery-powered robot which they believe may be the world`s smallest. The device, weighing less than 30g and occupying less than 4cm3 (0.25 cubic inches), has a tracked propulsion system powered by two miniature motors.

The researchers, based at the US Department of Energy`s Sandia National Laboratories, think that mini-robots could take over some of the duties handled by larger machines today.

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

The miniature robots will be able to venture into locations too small for their larger relatives. For example, they could scramble through pipes, or through collapsed buildings to search for signs of life or noxious chemicals. They could communicate with each other to behave in a similar way to swarms of insects.

The mini-robot, which can turn on a coin, travels at about 50cm a minute. It is powered by three watch batteries and incorporates an 8K ROM processor and a temperature sensor. Enhancements being considered include cameras, microphones, and communications devices.

According to Heller, the miniature machine has been made possible by the availability of unpackaged electronic components. These are assembled onto a simple, multi-chip module on a glass substrate.

The robot`s body is created using the rapid prototyping technique known as stereolithography. This forms shapes by depositing successive thin layers of polymers that are cured using a laser. The body has cavities for the robot`s batteries, substrate, axles, motors, switches and other parts.

The size of the robots is determined by the power source. "Batteries - both the physical size and battery life - have been one our biggest issues," says Heller. "The batteries need to run longer and be smaller."