Over at Submitterator, markarayner informs us that engineers at Case Western Reserve University developed a mechanical version of a key component of digital circuits for computers. Their mechanical inverter, the basis for many logic gates, is built from nanoscale levers instead of the transistors patterned onto traditional chips. The research was funded by the US Defense Advanced Research Projects Agency (DARPA) who are after electronics that aren't prone to failure under high heat, like that inside a jet or rocket engine control system. Te-Hao Lee and colleagues published their work in the current issue of the journal Science. From New Scientist:
Like a telegraph operator's Morse key, these levers physically make and break contact to pass or block currents.
Application of a voltage makes the levers move under electrostatic attraction. At 550 °C Lee's team managed to get the inverter to switch on and off 500,000 times a second – performing a computation with each cycle. The faster the switching speed, the zippier the computing. Lee predicts that switching speeds of a billion times a second (1 gigahertz) are possible. That might not sound fast by the standards of desktop PCs, which often run at speeds in excess of 2.5 gigahertz, but for control system applications it's more than adequate.