Abstract: Methods and apparatus for making and sensing ice. Also, apparatus and methods for sensing the change of phase of a substance. In one embodiment, a fringe-effect capacitor is placed proximate to a substance, such as water, which is undergoing a phase change, such as the change of phase from the liquid state to the solid state. During this change, the dielectric constant of the substance changes, and thereby changes the electrical flux between conductors of the fringe-effect capacitor. Also, apparatus and methods as described above, and using a capacitor but not a fringe-effect capacitor.

Abstract: A solar sensor that utilizes a blocking element and curved reflective element between the sun and a photo-sensitive electronic device to provide high signal levels and the ability to shape the angular response of the overall sensor. A particular angular response can be achieved by combining the attenuating affects of the blocking element with the increased response affects of the curved reflector. These two elements may be combined into one physical structure, or may be separate. Further, the present invention contemplates the use of multiple blocking elements and multiple reflectors.

Abstract: A solar sensor that utilizes a blocking element and curved reflective element between the sun and a photo-sensitive electronic device to provide high signal levels and the ability to shape the angular response of the overall sensor. A particular angular response can be achieved by combining the attenuating affects of the blocking element with the increased response affects of the curved reflector. These two elements may be combined into one physical structure, or may be separate. Further, the present invention contemplates the use of multiple blocking elements and multiple reflectors.

Abstract: A detector for measuring the reflectivity of a pollution reduction coating, including a housing, a substantially transparent window formed in the housing, a light source operationally connected in the housing and adapted to shine out the window onto the coating and a photodetector assembly operationally connected in the housing. The photodetector assembly includes a first photodetector positioned to receive light from the light source reflected by the coating, a second photodetector positioned to receive light from the light source reflected only from the window, and a third photodetector positioned to receive light directly from the light source. The first and second photodetectors are substantially blocked from receiving light directly from the light source and the second photodetector is substantially blocked from receiving light from the light source reflected by the coating.