KentuckyFC writes "The vast majority of motors that power our planes, trains, and automobiles are heat engines. They rely on the rapid expansion of gas as it heats up to generate movement. But attempts to shrink them by any significant amount have mostly ended in failure. Today, the smallest heat engines have a volume of some 10^7 cubic micrometers. Now group of Dutch engineers has built a heat engine that is seven orders of magnitude smaller than this. The engine consists of a piezoelectric bar that expands and contracts in the normal piezoelectric way. However it also heats up and cools at the same time causing a thermal expansion and contraction, which lags the piezoelectric displacement. By carefully choosing the frequency of the driving AC current, the Dutch team found a resonant effect in which the thermal expansion and contraction amplifies the mechanical motion, making it a true heat engine. Operating the thermodynamic cycle in reverse turns the device into a heat pump or refrigerator. The total volume of the device is just 0.5 cubic micrometres."

Gizmodo highlights a very cool repurposing effort for the Wii's Balance Board accessory. Rather than the specialized force platforms used to quantify patients' ability to balance after a trauma like stroke, doctors at the University of Melbourne thought that a Balance Board might serve as well. Says the article: "When doctors disassembled the board, they found the accelerometers and strain gauges to be of 'excellent' quality. 'I was shocked given the price: it was an extremely impressive strain gauge set-up.'" Games controllers you'd expect to be durable and at least fairly accurate; what's surprising is just how much comparable, purpose-built devices cost. In this case, the Balance Board (just under $100) was compared favorably with a test platform that costs just a shade less than $18,000.