MicroElectroMechanical Systems (MEMS) sensors and other micro-sensors are now readily available. This makes it possible to use modem manufacturing technologies to produce affordable and highly functional groupings (clusters) of the small and capable sensors. They beneficially share computational, communication and power resources. Printed circuit boards a few centimeters on a side, populated with the sensors and other components by fast pick-and-place machines, can form the backbone of clusters for many applications. Uses include, but are not limited to: small weather stations; systems for analysis of the atmosphere and water; monitors of fluid and power distribution systems, machinery operation, and the status of buildings, facilities and highway systems; and robots for a variety of applications, notably solar system exploration. The calibration of micro-sensors, and the reliability of such sensors and clusters containing them, are issues that require additional research. Micro-sensor clusters offer near term benefits that will not be supplanted soon by the "systems on a chip" currently under development.