American boffins have worked out a way of running a computer on air. Minsoung Rhee and Mark Burns at the University of Michigan have built a machine that processes  binary signals by sucking air out of tubes to represent a 0, or letting it back in to represent a 1.

A chain of such 1s and 0s flows through the processor's channels, with pneumatic valves controlling the flow of the signals between channels. The pneumatic valves  are run by changing the air pressure in a small chamber below the air channel, separated from the circuit by a flexible impermeable membrane. When the lower chamber is filled with air the membrane pushes upwards and closes the valve, preventing the binary signal flowing across one of the processor's junctions. Sucking out the air from the chamber reopens the valve by forcing the membrane downwards, letting the signal move across the junction. Using the valves, the boffins produced a variety of logic gates, flip-flops and shift registers, which they linked together to create a working 8-bit microprocessor.

This makes for a processor which is just as powerful as a 1980s Nintendo only there are less games for it. Rhee and Burns think that their invention has the potential to improve the "lab-on-a-chip" devices tipped to automate complex chemistry tasks and improve disease testing, DNA profiling and other lab jobs. Logic circuits could be used to control such experiments and reduce running costs.