Patent Publication Number: US-2022236440-A1

Title: Apparatus, methods, and techniques of obscured feature detection with live wire detection

Description:
RELATED APPLICATIONS 
     The present application claims the benefit of priority under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application No. 63/141,904 entitled APPARATUS, METHODS, AND TECHNIQUES OF OBSCURED FEATURE DETECTION, filed Jan. 26, 2021, which is hereby incorporated by reference herein in its entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to obscured feature detectors that have both the capability to sense the location of obscured features (e.g., behind walls and beneath floors) and the ability to warn the user if live electrical wires are in the vicinity. 
     BACKGROUND 
     Locating obscured features such as beams, studs, joists and other elements behind walls and beneath floors is a common problem encountered during construction, repair and home improvement activities. Cutting or drilling into a wall, floor, or other supported surface to create an opening in the surface, while avoiding the underlying support elements, is a regular occurrence. Knowing where the support elements are positioned before beginning can be desirable so as to avoid cutting or drilling into the support elements. Anchoring a heavy object such as a picture, cabinet, or shelf to a support element obscured by a supported surface is also a common occurrence. In these cases, it is often desirable to install a fastener through the supported surface in alignment with an underlying support element. However, with the wall, floor or supported surface in place, the location of the support element is not visually detectable. 
     Obscured feature detectors with electronic sensors have also been developed to detect obscured features behind opaque surfaces. These detectors sense changes in capacitance on the examined surface that result from the presence of features positioned behind, beneath or within the surface. These changes in capacitance are detectable through a variety of surfaces such as wood, sheetrock, plaster and gypsum and do not rely on the presence of metal fasteners in the surface or obscured feature for activation of the sensor. 
     Simply detecting obscured structural features has limitations. Electrical wires can also be obscured behind an opaque surface. The electrical wires may not be near a support structure and regardless of location it may be desirable to avoid electrical wires, particularly if the wires are live. 
     Presently available obscured feature detectors with dual sensing capability exist to detect both obscured features and live electrical wires. The presently available obscured feature detectors use a live wire sensing element that is left electrically floating and is sensed. As a result, the live wire sensing element&#39;s voltage level oscillates in the presence of live electrical wire, though at a substantially lower voltage. An amplifier may be used to increase the signal strength of the sensed live wire sensing element. Further, these presently available obscured feature detectors continually sense the live wire sensing element and an algorithm facilitates determining whether to activate a warning signal to the user to warn that a live wire may be in vicinity. While the live wire sensing element is sensing (e.g., detecting an electrical field formed between the live wire sensing element and a live electrical wire), a separate set of circuitry and a separate set of sensor pads sense for the presence of obscured features (e.g., sense for electrical field formed between the obscured feature sensing pads and ground or reference). As a result, there is one set of circuitry for sensing of the live wires, and a separate set for sensing for the obscured features. Multiple sources of electrical fields may interfere with accurate obscured feature sensing. Stated differently, these presently available obscured feature detectors include distinct modes and mechanisms of sensing live electrical wires and sensing other obscured features, albeit packaged in a single product. 
     SUMMARY 
     The present disclosure is directed to apparatus, methods, and generally to devices to detect a presence of hidden or obscured objects or features behind opaque, solid surfaces, and more specifically to devices to locate beams, studs and columns behind walls and joists beneath floors and also to detect a presence of electrical wires behind walls and beneath floors. 
     Additional aspects and advantages will be apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top view of an obscured feature detector, according to one embodiment of the present disclosure. 
         FIG. 2  is a diagram of a bottom layer of a circuit board of an obscured feature detector, according to one embodiment of the present disclosure. 
         FIG. 3  shows the bottom layer of a circuit board of an obscured feature detector, according to another embodiment of the present disclosure. 
         FIG. 4  illustrates an obscured feature detector, according to another embodiment of the present disclosure. 
         FIG. 5  shows the bottom layer of a circuit board of an obscured feature detector, according to another embodiment of the present disclosure. 
         FIG. 6  shows the bottom layer of a circuit board of an obscured feature detector, according to another embodiment of the present disclosure. 
         FIG. 7  is a flowchart that illustrates a flow of the sensing operation, according to one embodiment of the present disclosure. 
         FIG. 8  is a block diagram of circuit, according to one embodiment of the present disclosure, that switches the live wire sensing elements between being connected to a reference, for obscured feature sensing, and being connected to sensing circuitry for sensing the presence of live wires. 
         FIG. 9  is a more detailed diagram of the circuit of  FIG. 8 . 
         FIG. 10  is a flowchart that illustrates a flow of the sensing operation, according to one embodiment of the present disclosure. 
         FIG. 11  is a block diagram of circuit, according to one embodiment of the present disclosure, that switches the live wire sensing elements between being connected to a reference, for obscured feature sensing, and being connected to sensing circuitry for sensing the presence of live wires. 
         FIG. 12  is a more detailed diagram of the circuit of  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present disclosure relates generally to devices to detect a presence of hidden or obscured objects or features behind opaque, solid surfaces, and more specifically to devices to locate beams, studs and columns behind walls and joists beneath floors and also to locate electrical wires behind walls and beneath floors. 
     Obscured feature detectors with dual sensing capability exist. These presently available dual-sensing obscured feature detectors use a live wire sensing element that is left electrically floating, and is sensed. As a result, a voltage level of the live wire sensing element oscillates in the presence of live electrical wire. For example, in the United States house wiring is commonly 120V, 60 Hz. Therefore, if the floating live wire sensing element is in the presence of a live electrical wire, it will also oscillate at 60 Hz. However, it will oscillate with a voltage will likely be substantially less than 120V. These presently available obscured feature detectors commonly apply an amplifier to increase the signal strength of the sensed live wire sensing element. The prior art obscured feature detectors continually sense the live wire sensing element. An algorithm may then determine whether to activate a warning signal to the user to warn that a live wire may be within a near vicinity. Concurrent with the live wire sensing element being sensed, a separate set of circuitry and separate set of sensor pads sense for the presence of obscured features. As a result, there is one set of circuitry for sensing of the live wires, and a separate set for sensing of the obscured features. This form of separate yet dual sensing has been commonly used in presently available obscured feature products. 
     A shortcoming of the prior art obscured feature detectors (sometimes also known as stud finders) is that the live wire sensing element can interfere with the sensing of obscured features. As the floating live wire sensing element oscillates it can interfere with the sensing of obscured features. Electrical fields formed by a live electrical wire and the floating live wire sensing element may impair accurate sensing of electrical fields generated for detection of obscured features. This problem becomes more pronounced with higher accuracy obscured feature detectors that have more sensor pads. 
     An embodiment of the present disclosure achieves higher accuracy obscured feature sensing and maintains the capability to warn the user if a live wire is present. It achieves higher accuracy sensing of obscured features, and at a very low cost. 
     The presently disclosed embodiments may achieve this result by interleaving the sensing of obscured features and live wires. For example, a multiplexer (MUX) may be used to couple a live wire sensing element to either sensing circuitry, or to a reference such as ground or an active shield. This interleaving can allow the live wire sensing element to float, while being sensed. The sensed signal may be amplified, such as by an op-amp, to make the signal more useable for communicating information to the user. For example, the amplified signal may be fed into an analog to digital converter (ADC). In some embodiments the ADC may be built into a microcontroller. In some embodiments it may be advantageous to only sense for about 2 cycles of the 60 Hz signal, which equates to about 33 milliseconds. By limiting the sensing time, it may be possible to make an obscured feature detector that is more responsive. Two cycles may be enough in some embodiments to identify that the signal is a 50 Hz or 60 Hz signal. In some embodiments the readings of the ADC will be recorded first, then processed second. In some embodiments, 100 samples taken over a period of about 33 milliseconds may be sufficient. 
     In some embodiments it may be advantageous to process the reading to determine if the reading comes primarily from a 50 Hz or 60 Hz source. If the signal seems to have a frequency that is approximately 50 Hz or 60 Hz it would indicate that it likely came from a live wire, rather than from a spurious source, and make it possible to more accurately predict if the readings came from a live wire. Therefore, in some embodiments it may be advantageous to employ digital filtering techniques to determine if the reading is primarily from a 50 Hz or 60 Hz source. There are many known techniques that can accomplish this that may be employed by those skilled in the art. Some of the techniques may include pattern matching the readings against predetermined wave shapes, or using digital low-pass and high pass filters to create band-pass filters to remove all but the 50 Hz or 60 Hz component, or other techniques. 
     After the live wire sensing is complete, the MUX may be switched to couple the live wire sensing element to a reference signal such as ground, or to active shield, or to another known reference signal. 
     Once the MUX couples the live wire sensing element to a known reference, then the sensing of the obscured features may take place. In some embodiments, digital processing of previously stored readings from the live wire sensing may take place simultaneously or otherwise concurrently with the sensing of obscured features. Likewise digital processing of the obscured feature detector readings may take place during the live wire sensing. 
     The obscured feature detector may include a sensing element with one or more sensing pads. When the sensing element is positioned on a surface at a location with no obscured feature behind the surface, the obscured feature detector measures the capacitance of the surface and the air behind the surface. When the sensing element is moved into a position having an obscured feature behind the surface, the apparatus  100  then measures the capacitance of the surface and the obscured feature, which has a higher dielectric constant than air. Accordingly, the obscured feature detector registers an increase in capacitance, which can then be used to trigger a feedback system, such as a proximity indicator display, to alert the user that an obscured feature has been detected behind the surface. 
     Additional background on sensing obscured features, may be obtained with reference to the following U.S. Pat. Nos. 8,476,912, 8,593,163, 8,669,772, 8,736,283, 8,791,708, 8,836,347, 8,884,633, 10,261,208, 10,613,243, 10,663,613, which may include additional information pertinent to the obscured feature detection disclosed herein. 
     Once the sensing of the obscured features is complete, then the MUX may be switched back such that the electrical wire sensing circuitry is once again coupled to the live wire sensing element. 
     Other functions and features can also be included in the disclosed obscured feature detector embodiments. For example, enhancements to the display can be included and the display can be updated to let the user know what has been sensed. The display may be updated between any step, or possibly between every step, and in some embodiments updating the display may only happen after a predetermined number of cycles has completed. 
     When obscured features are being detected, the live wire sensing element is coupled to a reference. In some embodiments the reference may be ground. In some embodiments the reference may be an active shield. In other embodiments it may be coupled to a different reference signal. It some embodiments it may be advantageous to make the reference be similar to the surroundings of the live wire sensing element. For example, if the live wire sensing element is surrounded by ground, it may be advantageous to make the reference ground. Likewise, if the live wire sensing element is surrounded by active shield it may be advantageous to make the reference to active shield. In some embodiments this will allow all of the sensor pads to have a more similar response and increase the ability to sense obscured features accurately. 
     A handheld apparatus for detection of obscured features and obscured live wires is used by scanning along a surface, such as a wall, with the apparatus which will provide feedback to a user in real time, typically by an audible or visible alarm, when an obscured feature or live wire is detected in the vicinity. The obscured feature detected by such devices may be an obstruction, like wood or metal studs, and can aid the user to determine a location to safely drill, nail, screw, dig, or the like. 
       FIG. 1  is a top view of an apparatus  100  for detection of obscured features and obscured live electrical wires, according to one embodiment. The apparatus  100  comprises a housing  102  that houses or otherwise supports indicator displays to visually alert a user when an obscured feature or live wire is detected. The housing  102  also includes sensing elements to sense location of an obscured feature or live electrical wire. The housing  102  may be in a shape, such as a rectangular shape, to support obscured feature sensing elements arranged in a linear configuration on a circuit board of the apparatus for scanning an obscured surface. The apparatus  100  may include one or more types of indicators such as, for example, a proximity indicator display  104  to alert a user that an obscured feature is in the vicinity and a live wire indicator display  106  to alert the user that live wires are sensed nearby. 
     In some embodiments, the proximity indicator display  104  may include a visual indicator such as one or more illuminating elements (e.g., light, light emitting diode (LED)). A proximity indicator display  104  may include a plurality of visual indicators arranged in an array. One or more of the visual indicators (of the plurality of visual indicators) may be activated to indicate detection of an obscured feature. In some embodiments, a sensing element may include a plurality of pads, as will be described in greater detail below, and visual indicator may correspond to a sensor pad, such that a measured reading on a sensor pad that indicates detection of an obscured feature results in activation of one or more corresponding visual indicators of the proximity indicator display. In some embodiments, a proximity indicator may include an alarm or other audio device to provide an audible alert to a user. In  FIG. 1 , the apparatus  100  includes a proximity indicator display  104  that includes an array of LEDs extending along a length of the apparatus  100 . As an obscured feature is detected, one or more of the LEDs is activated to indicate a location of the obscured feature along a length of the apparatus  104 , providing clarity as to a location of where the obscured feature is positioned and where the obscured feature is not. 
     In some embodiments, the live wire indicator display  106  may include one or more visual indicators, such as one or more illuminating elements (e.g., a light, LED). In some embodiments, a live wire indicator may include an alarm or other audio device to provide an audible alert to a user. 
       FIG. 2  is a diagram of a bottom layer of a circuit board  200  in an apparatus for detection of obscured features and obscured live electrical wires, according to one embodiment of the present disclosure. The circuit board  200  can be included in the apparatus  100  of  FIG. 1A . The circuit board  200  includes an obscured feature sensing element  202  that comprises a plurality of sensing pads  202   a - 202   l  that are used to sense presence of an obscured feature in the vicinity when scanning a surface. The obscured feature sensing element  202  performs a sensor reading of a surface to detect obscured features. The sensing element  202 , collects sensor readings from each sensing pad  202   a - 202   l,  compares the readings, and the one or more sensing pads with the highest readings are interpreted to be near the location of an obscured feature. When the obscured feature sensing pads  202   a - 202   l  are placed on a surface at a location with no obscured feature behind the surface, the apparatus  100  measures the capacitance of the surface and the air behind the surface. When the sensing pads  202   a - 202   l  are moved into a position having an obscured feature behind the surface, the apparatus  100  then measures the capacitance of the surface and the obscured feature, which has a higher dielectric constant than air. Consequently, the apparatus  100  registers an increase in capacitance, which can then be used to trigger a feedback system, such as a proximity indicator display (e.g., the display  104  of  FIG. 1A ), to alert the user that an obscured feature has been detected behind the surface. 
     The obscured feature sensing element  202  is configured to form a first end of an electric field and to take a sensor reading of the electric field, in which the electric field varies based on proximity of the sensor element to surrounding objects and on material property of each of the surrounding objects. In  FIG. 2 , the obscured feature sensing element  202  includes a plurality of sensor pads  202   a - 202   l  arranged linearly. Each of the sensor pads  202   a - 202   l  are configured to form a first end of a respective corresponding electric field and to take a sensor reading of the corresponding electric field. The sensor pads  202   a - 202   l  may have a rectangular shape, a symmetric shape, an asymmetric shape, an irregular shape, or another complex-geometry shape, to produce a uniform sensor field among a group of sensor pads. The shapes may be formed so that a similar signal response in each sensor pad is produced. The circuit board  200  includes a common plate  204  to form a second end of the corresponding electric field of the obscured feature sensing element. The common plate  204  may be an active shield plate  204  which may be driven as an active shield. The active shield may be driven by the same signal as sensor pads  202   a - 202   l  . The bottom layer of circuit board  200  also include ground plates  206   a - 206   c . The ground plates  206   a - 206   c  may be connected to the circuit ground. 
     For detection of live electrical wires, the bottom layer of circuit board  200  further includes live wire sensing elements  208   a  and  208   b  for detection of live wires in the vicinity. Live wire sensing elements  208   a  and  208   b  may be either coupled to a reference such as the ground plates  206   a ,  206   b ,  206   c  or the active shield  204  when the apparatus is detecting obscured features, or the live wire sensing elements  208   a  and  208   b  may be left floating to detect the presence of live electrical wires. The live wire sensing elements  208   a  and  208   b  can be positioned adjacent to and between a plurality of ground plates  206   a ,  206   b ,  206   c . The mechanism of how live wires are detected is explained later in this disclosure. 
       FIG. 3  is a diagram of a bottom layer of circuit board  300 , according to an embodiment of the present disclosure. The circuit board  300  may be integrated or otherwise included in an apparatus, such as the apparatus  100  of  FIG. 2 , which detects obscured features and obscured live wires. The circuit board  300  includes an obscured feature sensing element  302 , a common plate  304  which is an active shield plate driven as active shield, and a single ground plate  306  which may be connected to circuit ground. The obscured feature sensing element  302  comprises a plurality of sensing pads  302   a - 302   k  that are used to sense presence of an obscured feature in the vicinity when scanning a surface. The sensing pads  302   a - 302   k  can be uniformly rectangular and primarily arranged in a generally linear fashion, and those pads  302   a ,  302   b ,  302   j ,  302   k  at the peripheral ends may be slightly adjusted to enhance uniformity of sensing at the peripheral ends. The sensing pads  302   a - 302   k  each perform a reading of a surface, then the readings are compared to recognize or otherwise identify which of the sensing pads  302   a - 302   k  sensed the highest reading(s) of the surface because the highest reading(s) may indicate a detection of an obscured feature. Sensing pads  302   a ,  302   b ,  302   j ,  302   k  that are positioned near the ends in an array of sensing pads  302  may respond to obscured features in a different manner, such as by responding with a disproportionately higher reading (due to producing electric fields that extend beyond the array of the sensing pads  302 ) when compared to responses of those located near the center of the array of sensing pads  302 . This issue may be particularly evident in a linearly-arranged group of sensing pads when the obscured feature detector is moved from a thinner or less dense surface to a thicker or more dense surface. The sensing pads of the sensing element  302  that are positioned near the peripheral ends, for example sensing pads  302   a ,  302   b ,  302   j , and  302   k , are positioned in a way that the sensing pads  302   a - 302   k  form an arcuate pattern on the circuit board  300  as shown in  FIG. 3 . The circuit board  300  also includes active shield rods  310   a  and  310   b  positioned between the plurality of sensing pads  302   a - 302   k  of the sensing element  302 . The active shield rods  310   a - 310   f  are electrically connected to the active shield  304  and may provide increased parallelism such that the sensing element  302  produces a more uniform response when detecting presence of an obscured feature, thereby increasing the ability of the apparatus  100  to sense obscured features. 
     For detecting obscured live wires behind a surface, the circuit board  300  further includes a wire sensing element comprising one or more wire sensing wires  308   a - 308   d  (collectively considered “wire sensing element  308 ”). Each of these one or more wires  308   a - 308   d , when left floating, can be used for detection of live wires nearby. The wire sensing element  308  is coupled to a reference, such as the active shield  304  or the ground plate  306 , when the apparatus is detecting obscured features instead of live wires. Each of the one or more wires  308   a - 308   d  of the wire sensing element  308  is located between the plurality of sensing element pads  302 . 
       FIG. 4  is a top view of an obscured feature and live wire detection apparatus  400 , according to another embodiment of the disclosure. Similar to the apparatus  100  of  FIG. 1 , the apparatus  400  of  FIG. 4  is used by scanning an opaque surface  401   a , such as sheetrock, to sense and detect an obscured feature  401   b  and/or live wire  401   c . The apparatus  400  includes a housing  402  that can house or otherwise support an indicator display  404  that can visually alert a user when the apparatus  400  detects an obscured feature or live wire. The indicator display  404  can indicate to a user the position of the obscured feature by displaying an inactive state  404   a  where an obscured feature is not sensed and by displaying an active state  404   b  where an obscured feature is detected. The indicator display  404  also includes a proximity indicator  404   c  that alerts the user when an obscured feature is sensed in the vicinity. The indicator display  404  can also include a live wire indicator  406  to alert the user when a live wire is sensed. The housing  400  further comprises a handle  408  and a battery cover  410  and is in a shape that supports sensing pads arranged in a square pattern on a circuit board. Sensing pads that sense for obscured features may be in a non-linear configuration, such as within a square area, for improved uniform response of the group of sensing pads. 
       FIG. 5  is a view of a bottom of a circuit board  500  of an obscured feature detector, according to another embodiment of the present disclosure. The circuit board  500  may be integrated or otherwise included in an apparatus that detects obscured features and live wires, such as the apparatus  400  of  FIG. 4 . The circuit board  500  includes a sensing element  502  that comprises a plurality of sensing pads  502   a - 502   f  arranged in a square pattern, square-like pattern, or other symmetrical arrangement. The circuit board  500  may be multi-layered. Sensing pads  502   e  and  502   f  may be in the bottom layer of circuit board  500  or rather may be in a different layer of the circuit board  500 . The circuit board  500  also includes a common plate  504 , which can be an active shield plate driven as an active shield. The active shield plate  504   a  may not be on the bottom layer of the circuit board  500 , but on a layer above The active shield plate  504   b  may also be on a different layer of the circuit board  500  instead of the bottom layer shown in  FIG. 5  and positioned in a center of the sensing element  502  when viewed from the bottom of circuit board  500 . The circuit board  500  further includes a ground plate  506  which may be connected to circuit ground and located between two live wire sensing elements  508  shown as live wire sensing pads  508   a  and  508   b  positioned near an end or adjacent to the sensing element  502  on the circuit board  500  in  FIG. 5 . The live wire sensing elements  508  are either coupled to a reference (such as active shield of ground) when obscured feature detection is occurring or may be left floating to sense the presence of live wires. 
       FIG. 6  is a view of a bottom of a circuit board  600  of an obscured feature detector, according to another embodiment of the present disclosure. The circuit board  600  may be integrated or otherwise included an apparatus that detects obscured features and live wires, such as apparatus  400 . The circuit board  600  includes a sensing element  602  comprising a plurality of sensing pads  602   a - 602   f . The sensing pads  602   a - 602   f  are arranged in a square pattern. The circuit board  600  further comprises a common plate which is an active shield plate driven as active shield and comprises active shield plates  604   a  and  604   b . The active shield plate  604   a  may not be on the bottom layer of circuit board  600 , but on a layer above. Active shield plate  604   b  may also be on a different layer of circuit board  600  and positioned in the center of sensing element  602  when viewed from the bottom of circuit board  600 . The circuit board  600  further includes a ground plate  606  near an end or adjacent to the sensing element  602  on circuit board  600  and may be connected to circuit ground. For live wire sensing, circuit board  600  includes a live wire sensing element which comprises a live wire sensing rod, two of which are shown as live wire sensing rods  608   a  and  608   b  in  FIG. 6 . The live wire sensing rods  608   a ,  608   b  are coupled to a reference (such as the active shield of ground) when obscured feature detection is occurring or may be left floating to sense the presence of live wires. 
       FIG. 7  is a flow diagram of a sensing operation, according to an embodiment of the present disclosure. In this embodiment, a multiplexer (MUX) is used to couple  702  a live wire sensing element to either an electrical wire sensing circuitry or to a reference such as ground, an active shield, or another known reference signal. The sensing operation includes coupling a live wire sensing element to an electrical wire sensing circuitry using the MUX. An obscured live electrical wire is sensed  704  while the live wire sensing element is coupled to the electrical wire sensing circuitry. After completion of sensing live electrical wires, the MUX decouples  706  the live wire sensing element from electrical wire sensing circuitry and couples  708  the live wire sensing element to a reference such as ground or active shield. Location of an obscured feature is then sensed  710  with the live wire sensing element coupled to the reference. It may be advantageous to select a reference that is similar to its surroundings, for example, if the live wire sensing element is surrounded by ground, it may be advantageous to make the reference be ground. Such selection can make sensor pads have a more similar response and increase the ability to sense obscured features accurately. Once the sensing of obscured features has been completed, the MUX can be switched to decouple  712  the live wire sensing from the reference and back to coupling  702  the electrical wire sensing circuitry to the live wire sensing element. This interleaving of the live wire sensing element between the electrical wire sensing circuitry and a reference is repeated during operation to sense live electrical wires and obscured features. 
       FIG. 8  is a block diagram of a circuit  800  of an obscured feature detector that detects both obscured features and live wires, according to one embodiment of the present disclosure. The circuit  800  switches a live wire sensing element  808  between being connected to a reference for obscured feature sensing and being connected to sensing circuitry for sensing the presence of live wires. In this circuit  800 , a microcontroller  802  provides a MUX Selector signal  804  to drive a MUX  806 , which is to couple a live wire sensing element  808  to an electrical wire sensing circuitry  810 . The MUX Selector signal  804  may be responsible for selecting if the live wire sensing element  808  is coupled to a reference, in this case an active shield driving circuitry  812  (or ground) or is coupled to the electrical wire sensing circuitry  810 . A signal  809  is provided via the MUX to the electrical wire sensing circuitry  810 . A signal  814  from the electrical wire sensing circuitry  810  is sent to the microcontroller  802 . In one embodiment, the electrical wire sensing circuitry  810  in effect amplifies the signal  809 , which is simply the MUX  806  passing the signal on the live wire sensing element  808 . 
     The microcontroller  802  is also coupled with obscured feature sensing pads  816  via an obscured feature sensing circuit  818 . The obscured feature sensing circuit  818  communicates with a reference circuitry, such as an active shield driving circuitry or ground  812 , which is connected to the MUX  806  that can couple the live wire sensing element  808  either to the electrical wire sensing circuitry  810  or the reference  812 . 
     In the diagram of  FIG. 8 , the wires (or lines) shown without arrows are bi-directional, while the wires (or lines) shown with only on arrow are unidirectional. 
       FIG. 9  is a more detailed circuit diagram of a circuit  900  of an obscured feature detector that switches a live wire sensing element  908  between being connected to a reference for obscured feature sensing and being connected to sensing circuitry for sensing the presence of live wires, according to one embodiment of the present disclosure. For example, the circuit  900  could be identical or similar to the circuit  800  of  FIG. 8 . 
     A microcontroller  902  drives a MUX selector signal  904 , which is digital output provided to a MUX  906  that can couple a live wire sensing element  908  either to electrical wire sensing circuitry  910  or a reference such as ground or active shield  912 . An example of a microcontroller is a STM32G3157GW. 
     The MUX  906  can have six ports, ports  1 - 6 . The live wire sensing element  908  may be one or more live wire sensing rods or live wire sensing pads connected to the MUX  906 , for example to port  4  of the MUX  906 . An example of a MUX  906  is a 74LVCIG3157GW. 
     The microcontroller  902  is fed signal  909   a , which is an amplified form of the signal  909  from the live wire sensing element  908 , as amplified by an operational amplifier (op-amp)  914 . The op-amp  914  and associated resistors and capacitors can function as an amplifier. For example, a signal  909  from the MUX  906  can be provided through MUX port  1  to op-amp  914 , which produces the amplified signal  909   a  that is passed on to the microcontroller  902 . An example of an op-amp  914  is a AZV831K. 
     The microcontroller  902  can convert the signal from the live wire sensing element  908  to a digital signal via an analog to digital converter (ADC). The electrical wire sensing circuitry may comprise an analog to digital converter. 
     The microcontroller  902  is also connected to obscured feature sensing element  916  via obscured feature sensing circuitry  918 . An example of the obscured feature sensing circuitry  918  shown in  FIG. 9  is a AD7147. There may be numerous obscured feature sensing pads as an obscured feature sensing element  916 . The obscured feature sensing circuitry  918  is linked to active shield driving circuitry  912  then to the MUX  906 , for example to MUX port  3 . Another example of an obscured feature sensing circuit  918  is AD7147PAC PZ-RL. In  FIG. 9 , the AD7147 obscured feature sensing circuitry  918  performs the obscured feature sensing and communicates directly with the microcontroller  902 . The remaining MUX ports  5  and  2  may be used to supply battery voltage and common ground, respectively. Additional elements not shown in  FIG. 9  and/or otherwise omitted from this discussion can include powers and grounds, display circuitry, and other signals as these are already known in the art or otherwise understood by one skilled in the art. 
       FIG. 10  is a flow diagram of a sensing operation, according to another embodiment of the present disclosure. In this embodiment, a live wire sensing element is driven  1002  to float. An obscured live electrical wire is sensed  1004  while the live wire sensing element is floating. After the obscured live electrical wire is sensed  1004 , the live wire sensing element is driven  1006  to a reference such as ground. Location of an obscured feature is then sensed  1008  with the live wire sensing element coupled to the reference. After completion of the sensing  1008  of obscured features, the live wire sensing element may again be driven  1002  to a floating state. This alternating of the live wire sensing element being driven alternately between a floating state and a reference is repeated to sense  1004  live electrical wires and to sense  1008  obscured features during sensing operation. A live wire sensing element may be driven  1002 ,  1006  by a controller, such as a microcontroller. A controller may be configured to intermittently drive the electrical wire sensing element to a driven value. For example, the live wire sensing element may be intermittently driven to a ground reference value, driven as an active shield, or driven to a value that matches the value on the sensor pads. 
       FIG. 11  is a block diagram of a circuit  1100  of an obscured feature detector that detects both obscured features and live wires, according to one embodiment of the present disclosure. The circuit  1100  of  FIG. 11  includes both obscured feature detection circuitry  1151  (e.g., an obscured feature detection component that may include obscured feature sensing circuitry  1118  and one or more sensor pads  1116 ) and live wire detection circuitry  1152  (e.g., a live wire detection component that may include a live wire sensing element  1108  and electrical wire sensing circuitry  1110 ). The circuit  1100  switches a live wire sensing element  1108  between a state of floating (for sensing the presence of live wires) and a state of being connected to a reference (for sensing obscured features). A microcontroller  1102  is included in the circuit  1100  which provides an output signal  1104  to drive the live wire sensing element  1108  either to float or to a reference. The wire sensing element  1108  also is connected to live wire sensing circuitry  1110 . In a floating state of the live wire sensing element  1108 , a signal  1109  is provided to the electrical wire sensing circuitry  1110 . A signal  1114  from electrical wire sensing circuitry  1110  is sent to the microcontroller  1102 . In one embodiment, the electrical wire sensing circuitry  1110  in effect amplifies the signal  1109 . When the live wire sensing element  1108  is driven to a reference, such as ground, the signal  1114  is sent to microcontroller  1102  to in effect couple with and otherwise activate reading the obscured feature sensing pads  1116  via an obscured feature sensing circuit  1118 . 
       FIG. 12  is a more detailed circuit diagram of a circuit  1200  of an obscured feature detector that switches a live wire sensing element  1208  between being connected to a reference for obscured feature sensing and being connected to sensing circuitry for sensing the presence of live wires, according to one embodiment of the present disclosure. For example, the circuit  1200  could be identical or similar to the circuit  1100  of  FIG. 11 . The live wire sensing element  1208  may comprise at least a portion of a common plate, such as an active shield plate described above with reference to  FIGS. 2-6 . 
     A microcontroller  1202  drives a signal  1204  that can couple a live wire sensing element  1208  to electrical wire sensing circuitry  1210 . An example of a microcontroller is a STM32G3157GW. The signal  1204  is set to float or to a reference. 
     The microcontroller  1202  is fed a signal  1209   a  that is an amplified form of a signal  1209  from the live wire sensing element  1208 , as amplified by an operational amplifier (op-amp)  1214 . The op-amp and associated resistors and capacitors can function as an amplifier. For example, a signal  1209  to op-amp  1214 , which produces the amplified signal  1209   a , is passed on to the microcontroller  1202 . An example of an op-amp  1214  is a AZV831K. 
     The electrical wire sensing circuitry  1210  may comprise an analog to digital converter. It may be that the microcontroller  1202  can convert the signal from the live wire sensing element  1208  to a digital signal via an analog to digital converter (ADC). 
     The microcontroller  1202  is also connected to an obscured feature sensing element  1216  via obscured feature sensing circuitry  1218 . An example of the obscured feature sensing circuitry  1218  shown in  FIG. 12  is a AD7147. There may be numerous obscured feature sensing pads as an obscured feature sensing element  1216 . Another example of an obscured feature sensing circuit  1218  is AD7147PAC PZ-RL. In  FIG. 12 , the AD7147 obscured feature sensing circuitry  1218  performs the obscured feature sensing and communicates directly with the microcontroller  1202 . Additional elements not shown in  FIG. 12  and/or otherwise omitted from this discussion can include powers and grounds, display circuitry, and other signals as these are already known in the art or otherwise understood by one skilled in the art. 
     EXAMPLES 
     The following provide one or more examples of embodiments of the present disclosure. 
     Example 1. An apparatus for detecting obscured features and obscured electrical wires, the apparatus comprising: an obscured feature sensing component to sense a feature obscured behind a surface and alert a user; a live wire sensing component to sense a live wire obscured behind the surface and alert the user, the live wire sensing component comprising: a live wire sensing element to detect an obscured live electrical wire; electrical wire sensing circuitry to receive signals originating from live wire sensing element; and a live wire indicator to alert the user of a detected live electrical wire, based on the signals originating from the live wire sensing element; and a selector switch to interleave sensing of obscured features by the obscured feature sensing component and sensing of live wires by the live wire sensing component, wherein the selector switch is configured to alternately couple the electrical wire sensing element to the electrical wire sensing circuitry or to a driven signal. 
     Example 2. The apparatus of Example 1, wherein the electrical wire sensing circuitry comprises a microcontroller to receive the signals originating from live wire sensing element and to drive the live wire indicator to alert a user of a detected live electrical wire. 
     Example 3. The apparatus of Example 2, wherein the microcontroller is operably coupled to the obscured feature sensing component and drives an obscured feature indicator based on a sensor reading of the obscured feature sensing component. 
     Example 4. The apparatus of Example 1, wherein the selector switch comprises a multiplexer (MUX). 
     Example 5. The apparatus of Example 1, wherein the obscured feature sensing component comprises: an obscured feature sensing element to sense location of an obscured feature; obscured feature sensing circuitry operatively coupled to the obscured feature sensing element, the obscured feature sensing circuitry configured to measure a sensor reading on the obscured feature sensing element; an obscured feature indicator to alert a user that an obscured feature has been detected behind the surface, based on the sensor reading; 
     Example 6. The apparatus of Example 5, wherein the obscured feature sensing element comprises a plurality of sensor pads arranged linearly to form a sensor array, wherein the sensor pads are each configured to form a first end of a respective corresponding electric field and to take a sensor reading of the corresponding electric field. 
     Example 7. The apparatus of Example 6, further comprising a common plate to form a second end of each respective corresponding electric field. 
     Example 8. The apparatus of Example 7, wherein the common plate comprises an active shield at the driven signal. 
     Example 9. The apparatus of Example 7, wherein the common plate is tied to ground. 
     Example 10. The apparatus of Example 1, further comprising an analog-to-digital converter (ADC) to convert the signals originating from live wire sensing element to a digital signal for the electrical wire sensing circuitry. 
     Example 11. An apparatus for detecting obscured features and obscured electrical wires, the apparatus comprising: an obscured feature sensing element to sense location of an obscured feature; obscured feature sensing circuitry operatively coupled to the obscured feature sensing element, the obscured feature sensing circuitry configured to measure a sensor reading on the obscured feature sensing element; an obscured feature indicator to alert a user that an obscured feature has been detected behind the surface, based on the sensor reading; a live wire sensing element to detect an obscured live electrical wire; electrical wire sensing circuitry operatively coupled to the live wire sensing element, the electrical wire sensing circuitry to receive signals originating from live wire sensing element; a live wire indicator to alert the user of a detected live electrical wire, based on the signals originating from the live wire sensing element; and an interleaving component to interleave the sensing of obscured features and the sensing of live wires, wherein the interleaving component is configured to alternately couple the electrical wire sensing element to the electrical wire sensing circuitry or to a reference value (e.g. the common plate) separately, wherein coupling the live wire sensing element to the electrical wire sensing circuitry allows sensing of a live electrical wire and coupling the live wire sensing element to the reference value allows sensing of obscured features. 
     Example 12. The apparatus of Example 11, wherein the electrical wire sensing circuitry comprises a microcontroller to receive the signals originating from the live wire sensing element and to drive the live wire indicator to alert a user of a detected live electrical wire. 
     Example 13. The apparatus of Example 12, further comprising an analog-to-digital converter (ADC) to convert the signals originating from live wire sensing element to a digital signal for the microcontroller. 
     Example 14. The apparatus of Example 12, wherein the microcontroller is operably coupled to obscured feature sensing circuitry and drives the obscured feature indicator based on the sensor reading. 
     Example 15. The apparatus of Example 11, wherein the obscured feature sensing circuitry comprise a microcontroller to drive the obscured feature indicator based on the sensor reading. 
     Example 16. The apparatus of Example 15, wherein the microcontroller receives the signals originating from live wire sensing element and activates the live wire indicator based on the signals to alert a user of a detected live electrical wire. 
     Example 17. The apparatus of Example 11, wherein the interleaving component comprises a multiplexer (MUX). 
     Example 18. The apparatus of Example 11, further comprising: a common plate, wherein the obscured feature sensing element is configured to form a first end of a corresponding electric field and to take a sensor reading of the corresponding electric field, wherein the corresponding electric field varies based on a proximity of the sensing element to one or more surrounding objects and on a material property of each of the one or more surrounding objects, and wherein the common plate is configured to form a second end of the corresponding electric field of the obscured feature sensing element. 
     Example 19. The apparatus of Example 18, wherein the common plate comprises an active shield driven at the known reference. 
     Example 20. The apparatus of Example 18, wherein the common plate is tied to ground. 
     Example 21. The apparatus of Example 11, wherein the obscured feature sensing element comprises a plurality of sensor pads arranged linearly to form a sensor array, wherein the sensor pads are each configured to form a first end of a respective corresponding electric field and to take a sensor reading of the corresponding electric field, and wherein a common plate is configured to form a second end of each respective corresponding electric field. 
     Example 22. The obscured feature detector of Example 21, wherein the sensor pads are each driven with the same signal simultaneously. 
     Example 23. An obscured feature detector for detecting obscured features and obscured electrical wires, comprising: an obscured feature sensing element for sensor reading at a surface, the obscured feature sensing element configured to form a first end of a corresponding electric field and to take a sensor reading of the corresponding electric field, wherein the corresponding electric field varies based on a proximity of the sensor element to one or more surrounding objects, including the surface, and on a material property of each of the one or more surrounding objects; a common plate to form a second end of the corresponding electric field of the obscured feature sensing element; obscured feature sensing circuitry operatively coupled to the obscured feature sensing element, the obscured feature sensing circuitry configured to measure the sensor readings on the obscured feature sensing element; a live wire sensing element; an interleaving component [[multiplexer (MUX)]] to interleave the sensing of obscured features and the sensing of live wires, wherein the interleaving component is configured to alternately couple the electrical wire sensing element to the electrical wire sensing circuitry or to the common plate separately, wherein coupling the live wire sensing element to the electrical wire sensing circuitry allows sensing of live electrical wire and coupling the live wire sensing element to a known reference signal allows sensing of obscured features; and a microcontroller to drive the interleaving component, to receive signals originating from the live wire sensing element, and to activate one or more indicators based on the signals originating from the live wire sensing element and the measurements of the sensor readings on the obscured feature sensing element. 
     Example 24. The obscured feature detector of Example 23, wherein the microcontroller is further to convert the signals originating from the live wire sensing element to a digital signal. 
     Example 25. The obscured feature detector of Example 23, further comprising: an obscured feature indicator to alert a user that an obscured feature has been detected behind the surface, based on the sensor reading, wherein the microcontroller activates the obscured feature indicator based on the measurements of the sensor readings on the obscured feature sensing element. 
     Example 26. The obscured feature detector of Example 25, wherein the obscured feature indicator comprises a plurality of light emitting diodes (LEDs) arranged in an array and at least one of the LEDs is lit by the microcontroller to indicate detection of an obscured feature. 
     Example 27. The obscured feature detector of Example 23, further comprising a live wire indicator to alert the user of a detected live electrical wire, wherein the microcontroller activates the live wire indicator based on the signals originating from the live wire sensing element. 
     Example 28. The obscured feature detector of Example 23, wherein the interleaving component comprises a multiplexer (MUX). 
     Example 29. The obscured feature detector of Example 23, wherein the common plate comprises an active shield driven at the known reference. 
     Example 30. The obscured feature detector of Example 23, wherein the common plate is tied to ground. 
     Example 31. The obscured feature detector of Example 23, wherein the obscured feature sensing element comprises a plurality of sensor pads arranged linearly to form a sensor array, wherein the sensor pads are each configured to form a first end of a respective corresponding electric field and to take a sensor reading of the corresponding electric field, and wherein a common plate is configured to form a second end of each respective corresponding electric field. 
     Example 32. An apparatus for detecting obscured features and obscured electrical wires, the apparatus comprising: an obscured feature sensing component to sense a feature obscured behind a surface and provide an alert for a user; a live wire sensing component to sense a live wire obscured behind the surface and alert the user, the live wire sensing component comprising: one or more live wire sensing elements to detect an obscured live electrical wire; electrical wire sensing circuitry to receive signals originating from live wire sensing element; and a live wire indicator to alert the user of a detected live electrical wire, based on the signals originating from the live wire sensing element; and a controller that is configured to intermittently drive the electrical wire sensing element to a driven value. 
     Example 33. The apparatus of Example 32, wherein the one or more live wire sensing elements is intermittently driven to a ground reference value. 
     Example 34. The apparatus of Example 32, wherein the one or more live wire sensing elements is intermittently driven as an active shield. 
     Example 35. The apparatus of Example 32, wherein the one or more live wire sensing elements is intermittently driven to a value that matches a value on sensor pads of the obscured feature sensing component. 
     Example 36. The apparatus of Example 32, wherein the electrical wire sensing circuitry comprises an analog to digital converter. 
     Example 37. The apparatus of Example 32, wherein the obscured feature sensing component performs capacitance readings of sensor plates to determine if an obscured feature is present. 
     Example 38. The apparatus of Example 32, wherein the one or more live wire sensing elements comprise at least a portion of the common plate. 
     Example 25. The apparatus of Example 32, wherein the one or more live wire sensing elements are located between sensor plates. 
     It will be obvious to those having skill in the art that many changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention. The scope of the present invention should, therefore, be determined only by the following claims.