US border security officials sponsored the development of a sensor at the University of Michigan that detects the gasses given off by the ink on paper bills, making it easier to catch currency smugglers.

Thanks to nanotechnology, sensors are becoming so small that we can monitor many conditions in ways never possible before. Dr. Kensall Wise, Director of the Center for Wireless Integrated MicroSystems at the University of Michigan calls wireless integrated microsystems (WMS) "the final frontier in the pervasiveness of microelectronics."

He's working on a micropower environmental monitor for the precision analysis of gaseous materials. This wristwatch-sized device can detect the presence of toxic gasses at the level of just 100 parts per trillion. It can also monitor temperature, humidity, pressure and more. It can recognize the presence of mustard gas in a building's air supply in just 4 seconds. (photo University of Michigan)