Abstract: A proximity sensor with an emitter capable of emitting energy waves of a selected wavelength and a detector capable of detecting energy waves with the selected wavelength, for example, energy waves in the infrared spectrum. The emitter and the detector are located in close proximity to one another on a single printed circuit board. When an article to be detected (e.g., any seed used in agriculture) passes the proximity sensor, the energy waves emitted by the emitter are reflected off the article and detected by the detector. The proximity sensor can be attached to a single wall of a container or to the side of a chute in order to detect the presence of articles in the container or to detect the passage of articles through the chute.

Abstract: Inventive electrical-computational method and system for aligning a magnetic gradiometer, and for determining magnetic gradients using a magnetic gradiometer which is inventively aligned. For each correlation of a correction magnetometer's vector with a reference magnetometer's vector, three correction coefficients and an offset coefficient are evaluated, using a mathematical approximation technique (such as least-squares) upon voltage outputs for various relative orientations of magnetic fields in relation to a magnetic gradiometer. An inventive matrix formula is used for determining magnetic gradients. A correction magnetometer matrix (matrix of voltages generated by each correction vector of the correction magnetometer) is multiplied by a coefficient matrix (matrix of correction and offset coefficients).

Abstract: Inventive electrical-computational method and system for aligning a magnetic gradiometer, and for determining magnetic gradients using a magnetic gradiometer which is inventively aligned. For each correlation of a correction magnetometer's vector with a reference magnetometer's vector, three correction coefficients and an offset coefficient are evaluated, using a mathematical approximation technique (such as least-squares) upon voltage outputs for various relative orientations of magnetic fields in relation to a magnetic gradiometer. An inventive matrix formula is used for determining magnetic gradients. A correction magnetometer matrix (matrix of voltages generated by each correction vector of the correction magnetometer) is multiplied by a coefficient matrix (matrix of correction and offset coefficients).