Building the mechanical nano computer

Long before silicon chips were to be found at the heart of the computer, even before transistors and thermionic valves, there was the concept of the mechanical computer, a machine to be built from levers, ratchets and cogs, complete with brass fittings and a Victorian flourish. The mechanical computer was never to be, at least not while microelectronics devices could carry out computations incredibly quickly by shuffling electrons.

Now, however, the emergence of nanotechnology brings with it the opportunity to manipulate materials close to the individual molecular level. So, could a nano-electromechanical computer be built?

Robert Blick and colleagues in the department of Electrical & Computer Engineering, at the University of Wisconsin-Madison, USA, believe so.

The UW-Madison team propose a fully mechanical computer based on electromechanical units, a billionth of a metre in size. These units might be based on tiny chunks of diamond or another superhard material that changes shape when an electric current is applied, so-called piezoelectric materials.

The units could be integrated into current silicon chip manufacturing processes and would operate essentially by pushing and pulling on each other, actuating connected elements to create switches, logic gates, and memory units. They would be the mechanical equivalent of the microscopic transistors on a silicon chip.

The fact that these nano-electromechanical units will be a thousandth the size of a transistor means that many, many more could be packed into the same space. The much smaller separation of logic gates also means that such a computer might eventually be made much faster than one based on the conventional silicon chip.

The researchers also point out that electromechanical elements will have several other advantages over silicon chip technology. They will use less power, for instance, and they will generate far less waste heat and so be able to operate at much higher temperatures without expensive and noisy cooling systems. They could also withstand voltage surges that can burn out a silicon chip. These advantages mean that the technology could be used in more extreme environments than today's computers, such as very hot conditions (exceeding 200 degrees Celsius), within high voltage electrical installations, or in the harsh environment of space.

This is a novel, breakthrough technology rather than an incremental change, which could lead to a new class of computer that is far more energy efficient than current machines, requires no cooling and can work in extreme environments. The technology exists to make the nano-electromechanical elements; the next step is to integrate them into a computational device and build a computer.