Abstract: A radon monitor includes a housing defining a housing cavity and having an opening in an exterior wall that is in fluid communication with the housing cavity to allow air to diffuse into and out of the housing cavity. The monitor also includes input and output units and a circuit board that is positioned in the housing cavity and supported by the housing. A passive, non-electrically powered sampling chamber defines a chamber cavity and is coupled to the circuit board. The circuit board defines a plurality of apertures that allow air to diffuse between the housing cavity and the chamber cavity. A detector for detecting radon is supported by the circuit board and positioned in the chamber cavity.

Abstract: A radon monitor includes a housing defining a housing cavity and having an opening in an exterior wall that is in fluid communication with the housing cavity to allow air to diffuse into and out of the housing cavity. The monitor also includes input and output units and a circuit board that is positioned in the housing cavity and supported by the housing. A passive, non-electrically powered sampling chamber defines a chamber cavity and is coupled to the circuit board. The circuit board defines a plurality of apertures that allow air to diffuse between the housing cavity and the chamber cavity. A detector for detecting radon is supported by the circuit board and positioned in the chamber cavity.

Abstract: Electronic precision measuring instruments such as calipers, micrometers, and the like, are adapted for measuring odd and irregular shapes. The electronics are built into the measuring instruments to respond to a pinion gear rolling along a rack of teeth responsive to the movement of a movable jaw mounted on an arm having a stationary jaw and the rack of gear teeth associated therewith. A matched pair of adapters fit over and lock to the jaws. The adapters include a set of pins having lengths and shapes which may fit into and around unique spaces and structures. The adapter pins may be either confronting or opposing to enable either inside or outside measurements.