A method for locating a casing collar in a well is disclosed. The method includes lowering an accelerometer into the well to slide along a casing wall of the well, generating a data log by measuring an accelerometer signal from the accelerometer as the accelerometer slides along the casing wall, analyzing, by a computer processor, the data log with respect to a predetermined data feature to detect an accelerometer signal event, and determining, by the computer processor and based on the accelerometer signal event, a location of the casing collar in the well.

A sensor, comprised of various mechanical components and electromechanical components, that measures/detects the relative position between two (2) or more objects and can measure/detect relative acceleration of one (1) or more objects, using fundamental natural physical forces, e.g. magnetism, electrostatics. More particularly, this invention relates to a sensor that can measure/detect the relative position of two or more objects and/or measure/detect the acceleration of one or more objects. Specifically, this invention uses fundamental physical forces in combination with mechanical components to actuate electro-optical-mechanical signal devices, e.g. electrical switches, optical switches, magnetic switches.

An example device for detecting acceleration using a spintronic Hall effect includes a spin Hall effect structure, a Magnetic Tunnel Junction (MTJ) element, a magnetic structure, and processing circuitry. The MTJ element includes a free structure, a pinned structure, and a tunnel barrier arranged between the free structure and the pinned structure. The magnetic structure is spaced apart from the spin Hall effect structure such that a magnetic field generated by the magnetic structure is moved relative to the spin Hall effect structure during acceleration. The processing circuitry is configured to generate electrical current through the spin Hall effect structure, measure a resistance at the MTJ element, and determine acceleration based on the resistance at the MTJ element.

An example device for detecting acceleration using a spintronic Hall effect includes a spin Hall effect structure, a Magnetic Tunnel Junction (MTJ) element, a magnetic structure, and processing circuitry. The MTJ element includes a free structure, a pinned structure, and a tunnel barrier arranged between the free structure and the pinned structure. The magnetic structure is spaced apart from the spin Hall effect structure such that a magnetic field generated by the magnetic structure is moved relative to the spin Hall effect structure during acceleration. The processing circuitry is configured to generate electrical current through the spin Hall effect structure, measure a resistance at the MTJ element, and determine acceleration based on the resistance at the MTJ element.

A single axis accelerometer comprising a swing arm pivotally attached to a frame is held in apposition to a stop by a threshold force until an experienced acceleration force greater than the threshold force causes a distal segment of the swing arm to release from the stop and move toward a sensor that is activated by a sensor trigger on the distal segment of the swing arm.

A single axis accelerometer comprising a swing arm pivotally attached to a frame is held in apposition to a stop by a threshold force until an experienced acceleration force greater than the threshold force causes a distal segment of the swing arm to release from the stop and move toward a sensor that is activated by a sensor trigger on the distal segment of the swing arm.

Accelerometer with Hall effect sensor. The accelerometer may have a rounded magnetic assembly with rounded flux concentrator, such as a C-shape or horseshoe. Opposing ends of the concentrator may each have a magnet and form a gap having a highly-concentrated, non-linear magnetic field. Opposing ends of the concentrator may have a reduced width, such as cone-shaped. A Hall sensor may be located within or near the gap. The sensor or magnet may be moveably supported by a spring. The sensor may move perpendicularly relative to a direction of the magnetic field lines. A second magnet may be included, for example adjacent the gap, to provide a second set of magnetic field lines with shallower gradient for lower sensitivity. Movement of the sensor within the two magnetic fields may provide multiple wide-ranging sensitivities, such as X V/g as well as X/500 mV/g or X/5,000 mV/g.

Accelerometer with Hall effect sensor. The accelerometer may have a rounded magnetic assembly with rounded flux concentrator, such as a C-shape or horseshoe. Opposing ends of the concentrator may each have a magnet and form a gap having a highly-concentrated, non-linear magnetic field. Opposing ends of the concentrator may have a reduced width, such as cone-shaped. A Hall sensor may be located within or near the gap. The sensor or magnet may be moveably supported by a spring. The sensor may move perpendicularly relative to a direction of the magnetic field lines. A second magnet may be included, for example adjacent the gap, to provide a second set of magnetic field lines with shallower gradient for lower sensitivity. Movement of the sensor within the two magnetic fields may provide multiple wide-ranging sensitivities, such as X V/g as well as X/500 mV/g or X/5,000 mV/g.

The invention relates to an acceleration sensor, especially a duplex acceleration sensor, an arrangement and a method for detecting a loss of road grip of a vehicle wheel (3). The acceleration sensor comprises a tube (5) having a longitudinal axis forming a circular arc segment, and two closed ends. A mass (15; 315) is arranged inside the tube (5) such that is able to move inside the tube (5) in the longitudinal direction thereof. A magnet arrangement (17; 203; 205; 317) is designed to counteract, by way of a magnetic force exerted on the mass (15; 315), a movement of said mass (15; 315) from an idle position (25), and a read-out unit (608) is designed to detect a movement of said mass (15) from the idle position (25).

The invention relates to an acceleration sensor, especially a duplex acceleration sensor, an arrangement and a method for detecting a loss of road grip of a vehicle wheel (3). The acceleration sensor comprises a tube (5) having a longitudinal axis forming a circular arc segment, and two closed ends. A mass (15; 315) is arranged inside the tube (5) such that is able to move inside the tube (5) in the longitudinal direction thereof. A magnet arrangement (17; 203; 205; 317) is designed to counteract, by way of a magnetic force exerted on the mass (15; 315), a movement of said mass (15; 315) from an idle position (25), and a read-out unit (608) is designed to detect a movement of said mass (15) from the idle position (25).