After the electronics revolution, mechanical computing machines seem to be the relics of a bygone age. Are they really? Two researchers in New Zealand have built their own updated version, which has great potential for robotics, the researchers say.

When designing their machine, they did not go back to the golden age of mechanics in the 18th century, but they did return in time to the work of Alan Turing (1912-1954). More precisely, they went back to what is known as the universal Turing machine. The British genius actually envisioned an automaton, a simple computer model which consists of three parts or internal states: memory and sets of instructions; read-write head; a strip of input tape, infinite in theory, that is marked out into squares. Rules determine the function of input symbols, and then the machine prints new symbols (standardised instructions encoded as numbers) on the tape. Anything can be calculated provided that the tape is long enough ? all (well-defined) problems can be solved by a single machine (that has the necessary programmes).

The simplest form of a Turing machine reads only three states (A, B, C), has two internal states (0, 1), moves the tape either left or right, and can do only six operations. It is easy to build, however, it is extremely difficult to programme.

The researchers from New Zealand made their computer out of a set of elastomers. Elastomers are polymers that expand or contract when a voltage is applied. These artificial muscles were set up so that they could operate sets of electrical relays that drove other muscles. Once the machine was built, the researchers calculated the expected results of operations, and checked them against the output of the computer. And the machine, 0.3 cubic metres in size with a computational speed of 0.15Hertz, made no mistakes. It lacks the tape capacity to calculate anything complicated, but in principle it can calculate anything. The operation of artificial muscles may be the starting point for future robots.