Patent Publication Number: US-2020284853-A1

Title: Hall Effect Sensor

Description:
BACKGROUND 
     Hall effect sensors, circuits which vary voltage based on a magnetic field, may be used in a variety of circumstances to detect the presence of static or dynamic magnetism. Such Hall effect sensors may be used, for example, to determine the revolutions per minute (RPM) of a wheel (e.g., in a vehicle) having a magnet attached to the wheel. Other uses of a Hall effect sensor may include determining the position and/or proximity of a wholly or partially magnetic object. Hall effect sensors may be preferred over other magnetic sensors, such as reed switches, because Hall effect sensors have particularly long lives and may allow for nuanced measurement of magnetic fields. 
     Modern Hall effect sensors are quite small and, while powerful, often require that magnetic fields be very close, be particularly oriented, and/or very strong for detection. But in many circumstances, placing a magnetic object closer to the Hall effect sensor may be undesirable at least because it may risk damaging the Hall effect sensor (e.g., if the object is a spinning disk). The orientation of a magnetic field may be difficult to ensure in circumstances where an object may easily move (e.g., such that the magnetic field is prone to rapid change). Also, a magnetic field may be difficult to measure if, for example, the desired object to be measured is a particularly weak permanent magnet. Previous solutions to such problems have been expensive, fragile, and/or reliant on a magnetic environment being controlled. 
     SUMMARY 
     The following summary presents a simplified summary of certain features. The summary is not an extensive overview and is not intended to identify key or critical elements. 
     Systems, apparatuses, and methods are described for a Hall effect sensor comprising a Hall effect integrated circuit (IC) and two or more rectangular flux guidance plates. The Hall effect IC may be any conventional Hall effect sensor such as, e.g., the DRV5013 Hall effect sensor sold by Texas Instruments of Dallas, Tex. Above the Hall effect IC, a first rectangular flux guidance plate may extend in a first direction such that the first rectangular flux guidance plate is at least partially on top of the Hall effect IC. Below the Hall effect IC, a second rectangular flux guidance late may extend in a second direction, opposite the first direction, such that the second rectangular flux guidance plate is at least partially below the Hall effect IC. The Hall effect IC, first rectangular flux guidance plate, and second rectangular flux guidance plate may be attached to a printed circuit board, which may comprise wiring such that voltage and current may be applied to the Hall effect IC. The printed circuit board may comprise one or more attachment points for connecting the Hall effect sensor to an object, such as a toy. 
     These and other features and advantages are described in greater detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Some features are shown by way of example, and not by limitation, in the accompanying drawings. In the drawings, like numerals reference similar elements. 
         FIG. 1  shows a side view of a Hall effect IC between a first arm and a second arm. 
         FIG. 2  shows a Hall effect sensor assembly comprising rectangular magnetic guidance plates. 
         FIG. 3  shows a region of magnetic sensitivity of the Hall effect sensor assembly. 
         FIG. 4  shows a cutaway view of the Hall effect sensor assembly. 
     
    
    
     DETAILED DESCRIPTION 
     The accompanying drawings, which form a part hereof, show examples of the disclosure. It is to be understood that the examples shown in the drawings and/or discussed herein are non-exclusive and that there are other examples of how the disclosure may be practiced. 
       FIG. 1  shows a side view of a Hall effect sensor apparatus  100  comprising a Hall effect IC  101  between a first arm  102   a  and a second arm  102   b . The Hall effect IC  101  shown in  FIG. 1  is an example, and other integrated circuits sensitive to the Hall effect may be used. The Hall effect IC  101  is located on a circuit board  103 . At opposite ends of the circuit board  103 , a first arm  102   a  and a second arm  102   b  are attached, which extend by a length L to overlap above and below the Hall effect IC  101  in an area designated as an overlap region  105 . The first arm  102   a  and the second arm  102   b  need not contact the Hall effect IC  101 ; rather, a gap  104   a  and a gap  104   b  separate the Hall effect IC  101  from the first arm  102   a  and the second arm  102   b , respectively. The gap  104   a  and/or the gap  104   b  may comprise air, all or portions of the circuit board  103 , glue, or the like. Thus, for example, while  FIG. 1  shows a gap  104   b  including air, the second arm  102   b  may physically contact the circuit board  103 , such that the gap  104   b  comprises the thickness of the circuit board  103 . 
     The Hall effect IC  101  may be configured to measure magnetism along one or more axes. For example, the Hall effect IC  101  may be one-axis, two-axis, or three-axis, meaning that it may detect magnetism along a single or a plurality of axes. If the Hall effect IC  101  is configured to detect magnetism along a plurality of axes, it may be biased to detect magnetism more strongly along a first axis as compared to a second and/or third axis. The first arm  102   a  and/or the second arm  102   b  may be aligned along one or more of these axes. 
     The circuit board  103  may be any element configured to hold the Hall effect IC  101 , the first aim  102   a , and/or the second arm  102   b . The circuit board  103  may comprise a non-conductive substrate and/or a conductive substrate. For example, one or more first portions the circuit board  103  may comprise a non-conductive but sturdy substance, whereas one or more second portions of the printed circuit board may be conductive and may couple the Hall effect IC  101  to a power source. 
     The first arm  102   a  and the second arm  102   b  may be magnetic guidance plates on opposite sides of the circuit board  103  which act as flux concentrators with respect to the Hall effect IC. The first arm  102   a  and the second arm  102   b  may be metal, made of a metallic substance, and/or may have properties which direct magnetism towards the Hall effect IC  101 . The first arm  102   a  and/or the second arm  102   b  may be configured to react to the presence of magnetism that need not be present at the Hall effect IC  101 . For example, the presence of magnetism at the first arm  102   a  may cause magnetism in the first arm  102   a  itself, which may cause corresponding magnetism at the Hall effect IC  101 . The first arm  102   a  and/or the second arm  102   b  may thereby extend the magnetic sensitivity of the Hall effect IC  101  in two directions (e.g., a first direction and a second direction, wherein the second direction is opposite the second direction) while simultaneously limiting the sensitivity of the Hall effect IC  101  in other directions. Additional rectangular magnetic guidance plates (not shown) may be implemented to add sensitivity of the Hall effect IC  101  to other axes. 
     The first arm  102   a  may have a curvature  106   a , and the second arm  102   b  may have a curvature  106   b , such that the arms may be curve towards and contact the circuit board  103 . The first arm  102   a  and/or the second arm  102   b  may otherwise be substantially rectangular. This contact occurs near the ends of the circuit board  103  such that the first arm  102   a  and the second arm  102   b  need not physically contact the Hall effect IC  101 . Connection of the first arm  102   a  and/or the second arm  102   b  may be made by, e.g., inserting the first arm  102   a  and/or the second arm  102   b  into a slot of the circuit board  103  and/or gluing the first arm  102   a  and/or the second arm  102   b  in place. The first arm  102   a  and the second arm  102   b  may both have a length L extending in different directions away from the Hall effect IC  101 , and both may cover the top and/or bottom of the Hall effect IC in the overlap region  105 . For example, as shown in  FIG. 1 , the first arm  102   a  may be above the Hall effect IC  101  and extend leftward from the Hall effect IC  101 , whereas the second arm  102   b  may be below the Hall effect IC  101  and may extend rightward from the Hall effect IC  101 . The first arm  102   a  and/or the second arm  102   b  may be additionally and/or alternatively referred to as flux concentrators. 
     The first arm  102   a  and/or the second arm  102   b  may be configured with respect to an axis. The Hall effect IC  101  may be particularly sensitive in a particular axis (e.g., to the left and right of  FIG. 1 ), and the first arm  102   a  and/or the second arm  102   b  may extend in opposite directions of this axis. Additionally or alternatively, the first arm  102   a  and/or the second arm  102   b  may be configured to extend in opposite directions along an axis other than that which the Hall effect IC  101  is sensitive. 
       FIG. 2  shows a diagonal perspective of the Hall effect sensor apparatus  100  comprising the Hall effect IC  101 , the first arm  102   a , and the second arm  102   b , as combined on the circuit board  103 . The circuit board  103  may comprise leads  203  connecting to the Hall effect IC  101  and one or more tab holes  204  for connecting the first arm  102   a  and/or the second arm  102   b  to the circuit board  103 . 
     The first arm  102   a  and/or the second arm  102   b  may be configured to attach above and/or below the Hall effect IC  101 . The first arm  102   a  and/or the second arm  102   b  may be curved or otherwise shaped to attach to the circuit board  103  using tabs and/or other fasteners. For example, the first arm  102   a  and/or the second arm  102   b  shown in  FIG. 2  may be attached to the printed circuit board using tabs inserted into the tab holes  204  of the circuit board  103 , but need not physically contact the Hall effect IC  101 . Not physically connecting to the Hall effect IC  101  may avoid adding additional substances (e.g., adhesive) to the Hall effect IC, as such substances may undesirably interfere with the sensitivity of the Hall effect IC  101 . 
     Use of two or more magnetic guidance plates, such as the first arm  102   a  and the second arm  102   b , may advantageously avoid shielding effects present with larger and/or longer metal or metallic flux guides. For example, removing the second arm  102   b  and lengthening the first arm  102   a  to the entire length of the circuit board  103  may undesirably cause the first arm  102   a  to act as a shield for magnetism, thereby potentially preventing magnetism from reaching the Hall effect IC. As such, the first arm  102   a  and the second arm  102   b  need not exhibit the same or similar responses to magnetism imposed on and/or near the Hall effect sensor apparatus  100 . 
     The circuit board  103  shown in  FIG. 2  may have a shape that is longer in one direction than another. For example, as shown in  FIG. 2 , the circuit board  103  may have a length (e.g., 40 mm) that is the combined length of the first arm  102   a  and the second arm  102   b  (e.g., each being 20 mm, or 40 mm total). The Hall effect IC may be, for example, 3 mm×3 mm. The small size of the circuit board  103  may advantageously allow it and the Hall effect IC  101  to be protected by the first arm  102   a  and/or the second arm  102   b . For example, the first arm  102   a  and/or the second arm  102   b  may be reinforced or otherwise designed with a thickness such that the Hall effect IC  101  is protected from damage. 
     The leads  203  may be configured to carry power to the Hall effect IC, and/or may be configured to transmit voltage corresponding to the Hall effect. The leads  203  may comprise wire, such as copper wire. The leads  203  may be configured such that the overall resistivity of the leads  203  is minimized. 
       FIG. 3  shows a flux concentration area  300  of the Hall effect sensor apparatus  100 . The Hall effect sensor apparatus  100  may be configured to detect magnetism on an axis. For example, as shown in  FIG. 3 , the vertical axis corresponds to two large regions of magnetic sensitivity (corresponding to the length of the first arm  102   a  and/or the second arm  102   b ), whereas the horizontal axis has less magnetic sensitivity. The Hall effect sensor apparatus  100  may therefore be configured to detect magnetism along a first axis, but not a second axis. Moreover, because the first arm  102   a  may be on top of the circuit board  103 , and because the second arm  102   b  may be below the circuit board  103 , magnetism above the circuit board  103  may be more readily detected by the first arm  102   a , whereas magnetism below the circuit board  103  may be more readily detected by the second arm  102   b . The first arm  102   a  and the second arm  102   b , by being located on opposite directions of an axis and on opposite sides of the circuit board  103 , may thereby advantageously expand the magnetic sensitivity of the Hall effect IC  101  far beyond its typical range. 
       FIG. 4  shows the Hall effect sensor apparatus  100  with the first arm  102   a  and the second arm  102   b  made transparent, revealing the tab holes  204 , the Hall effect IC  101 , and the overlap region  105 . As may be seen from the perspective in  FIG. 4 , the overlap region  105  comprises a portion of the length L of each of the first arm  102   a  and the second arm  102   b . For example, the overlap region  105  may be one-third of the length L of the first arm  102   a.    
     Although examples are described above, features and/or steps of those examples may be combined, divided, omitted, rearranged, revised, and/or augmented in any desired manner. Various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this description, though not expressly stated herein, and are intended to be within the spirit and scope of the disclosure. Accordingly, the foregoing description is by way of example only, and is not limiting.