Engineers have constructed a solar array smaller than a dime out f 20 solar cells, each cell tinier than a quarter of this lowercase "o." The mini photoelectric device only generates seven volts of electricity, but that could be enough to power microsensors like those military planners imagine will provide the soldier of the future with first-person-shooter-like battlefield intelligence. That's why the Army is a major sponsor of the project, which is described in the Journal of Renewable and Sustainable Energy.