before the various embodiments of the present invention are explained in detail , it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings . the invention is capable of other embodiments and of being practiced or of being carried out in various ways . also , it is to be understood that phraseology and terminology used herein with reference to device or element orientation ( such as , for example , terms like “ front ”, “ back ”, “ up ”, “ down ”, “ top ”, “ bottom ”, and the like ) are only used to simplify description of the present invention , and do not alone indicate or imply that the device or element referred to must have a particular orientation . in addition , terms such as “ first ”, “ second ”, and “ third ” are used herein and in the appended claims for purposes of description and are not intended to indicate or imply relative importance or significance . one embodiment of a clamp 10 is shown in perspective in fig1 , and from the side in fig2 a . fig2 b provides a side cutaway view of the illustrative embodiment along the length thereof . the illustrative embodiment of the clamp 10 generally includes a first portion 20 and a second portion 30 that are selectively positionable with respect to one another . the first and second portions 20 , 30 may be coupled via a positioner 24 as shown herein . in other embodiments of the clamp 10 , other structures and / or methods may be used to allow for the first portion 20 to be selectively secured in a position relative to the second portion 30 without limitation . a distal end 21 of the first portion 20 may extend beyond the corresponding end of the second portion 30 . however , in other embodiments of the clamp 10 the first and second portions 20 , 30 are approximately equal in length . in the illustrative embodiment the positioner 24 includes a positioner adjuster 24 b at a first end thereof and a positioner anchor 24 a at a second end thereof . a portion of the positioner 24 adjacent the positioner adjuster 24 b may pass through an aperture 22 formed in the first portion 20 , as best shown in fig1 & amp ; 2b . the aperture 22 may be configured as a slot to allow for various adjustments in the relative position of the first and second portions 20 , 30 . the positioner anchor 24 a may be placed within an anchor receiver 32 formed in the second portion 30 , also best shown in fig2 b . in this embodiment , the positioner 24 is generally configured as a bolt and nut , wherein the bolt is securely engaged with the second portion 30 and the nut serves as the positioner adjuster 24 b , whereby a user may adjust the distance between the first and second portions 20 , 30 . however , in other embodiments not pictured herein the positioner 24 may use different structures and / or methods to allow a user to adjust the distance between the first and second portions 20 , 30 . referring now generally to fig2 b and 3b , a sensor assembly 40 may also be placed between the first and second portions 20 , 30 . in the illustrative embodiment the sensor assembly 40 is positioned opposite the distal end 21 of the first portion 20 , but may be positioned elsewhere without limitation . in the illustrative embodiment of the clamp 10 , the sensor assembly 40 generally includes a biasing member 42 , a pin 46 , and a sensor 47 . the pin 46 may be affixed at one end thereof to the first portion 20 and extend downward through a spacer 44 and a biasing member 42 into a pin housing 36 affixed to the second portion 30 . in other embodiments of the clamp 10 , the pin housing 36 may be formed integrally within the second portion 30 . the pin 46 may be secured to the first portion 20 so that the position of the pin 46 is fixed with respect to the first portion 20 . the biasing member 42 may be positioned between the first and second portions 20 , 30 concentrically with the pin 46 and spacer 44 , which may be positioned between the biasing member 42 and first portion 20 . the end of the pin 46 opposite the first portion 20 may extend into an interface chamber 38 formed in the second portion 30 . the second portion 30 may be formed with one or more mounting apertures 37 therein . a mounting aperture 37 may be used to secure the second portion 30 and / or the clamp 10 to a structure and / or work surface , thereby providing a reference position for the clamp 10 and the first portion 20 . in other embodiments , the second portion 30 may be secured to a structure and / or work surface via welding . accordingly , the scope of the clamp 10 is not limited by the method and / or structure used to secure the clamp 10 and / or second portion 30 to a structure and / or work surface , and any suitable structure and / or method may be used without departing from the spirit and scope of the clamp 10 . a first end of a sensor 47 may be positioned within a sensor chamber 34 formed in the second portion 30 such that the position of the sensor 47 with respect to the second portion 30 is fixed . a second end of the sensor 47 may extend toward the interface chamber 38 adjacent the pin 46 . it is contemplated that the sensor 47 in the illustrative embodiment of the sensory assembly 40 will be configured as a proximity sensor . accordingly , the sensor 47 may be used to determine the distance between the first and second portions 20 , 30 . however , in other embodiments of the clamp 10 , the sensor 47 may be configured differently , such as a photo eye , or any other structure and / or method that functions to determine the distance between two objects as described in detail below . a coupling 48 may be positioned adjacent the sensor 47 . in the illustrative embodiment , the coupling is positioned opposite the interface surface 21 a toward the bottom of the second portion 30 . the coupling 48 may have a first inlet 48 a and / or angled inlet 48 b to provide a conduit to the sensor 47 . for example , the coupling 48 may be used to provide electrical energy to the sensor 47 . in other embodiments , the sensor 47 may be wireless , in which case a coupling 48 may not be necessary . the biasing member 42 may be configured to bias the first portion 20 away from the second portion 30 with a predetermined force for a predetermined clearance between the first and second portions 20 , 30 . alternatively , in embodiments of the clamp 10 in which a second portion 30 is not required ( described in detail below ), the biasing member 42 may be configured to bias the first portion 20 away from the work piece and / or work surface . decreasing the distance between the first and second portions 20 , 30 ( via the positioner adjuster 24 b in the illustrative embodiment ) brings the pin closer to the sensor 47 . a certain amount of force will be required to overcome the force of the biasing member 42 in order to bring the pin 46 in sufficient proximity to the sensor 47 such that the sensor 47 detects the presence of the pin 46 . in this manner , the biasing member 42 , pin 46 , and sensor 47 may be configured so that the sensor 47 detects the pin 46 when the clamp 10 has achieved a predetermined clamping force against a work piece ( not shown ) positioned between the interface surface 21 a and work surface ( not shown , but for most embodiments generally located under the interface surface 21 a adjacent the second portion 30 ). other types of sensor assemblies 40 may be used without limitation , and the optimal sensor assembly 40 and / or components thereof will vary from one application of the clamp 10 to the next . for example , in an embodiment not pictured herein , the sensor assembly 40 may include a strain gauge , and in another embodiment it may include some type of mems component . accordingly , any sensor assembly 40 that alerts a user when a specific clamping force has been achieved , and / or that functions to detect the distance between two objects may be used with the clamp 10 without limitation . additionally , the optimal forces , pressures , orientations , and / or dimensions of the various components of the clamp 10 will vary from one application of the clamp 10 to the next , and are therefore in no way limiting to the scope thereof . for example , in another embodiment of the clamp 10 not pictured herein , the sensor assembly 40 is positioned adjacent the interface surface 21 a such that it may directly detect the relative positions and / or forces of the first portion 20 and work piece . in such an embodiment a second portion 30 may not be needed , and it is contemplated that the positioner 24 may be engaged directly with the work surface . having described a preferred embodiment of the clamp 10 for certain applications , one method of using the clamp 10 will now be described . generally , the clamp 10 may verify that a user secured a work piece with proper force , and that the proper force is maintained . in the illustrative embodiment , a work piece may be positioned on a work surface , and the second portion 30 of the clamp 10 may be secured to that work surface . once the user is satisfied with the position of the work piece , the user may secure the position of the work piece using the clamp 10 . the user may decrease the distance between the first portion 20 and the second portion 30 ( and consequently the distance between the first portion 20 and the work piece and work surface ) via the positioner adjuster 24 b . in the illustrative embodiment of the clamp 10 this would be accomplished by tightening a nut ( positioner adjuster 24 b ) engaged with a bolt ( positioner 24 ). as the distance between the first and second portions 20 , 30 is decreased , the biasing member 42 is progressively compressed . eventually the distance will be decreased to the point that the sensor 47 will detect the pin 46 . for a given work piece dimension , the biasing member 42 , sensor 47 , and pin 46 may be configured so that when the sensor 47 detects the pin 46 , the first portion 20 is placing a predetermined force on the work piece . this allows the user to verify that the clamp 10 properly secures the work piece . in a similar fashion , the sensor assembly 40 may also be configured to alert the user if the clamp 10 does not maintain the predetermined force on the work piece , i . e ., if the clamp 10 becomes loose or dislodged . a plurality of clamps 10 may be used on a single work piece , and each clamp 10 may be in communication with a controller ( not shown ), which controller may be in communication with a machine ( e . g ., cnc mill , lathe , etc .). the controller may be configured so that if any clamp 10 fails to achieve and / or maintain the proper clamping force , the machine reverts to a fail mode in which no work is performed on the work piece , and in which the work piece cannot be moved or repositioned . the user may be alerted to this situation and inspect and / or adjust each clamp 10 until the proper clamping force is achieved on each clamp 10 . it is contemplated that the controller may also be configured to identify the specific clamp 10 that has failed to achieve or maintain the proper clamping force . various other electrical components that may be required to facilitate the operation of the clamp 10 , such as capacitors , resistors , etc . are not shown herein for purposes of clarity , and are in no way limiting to the scope of the clamp 10 . the clamp 10 and various components thereof may be constructed of any suitable material for the specific application of the clamp 10 . it is contemplated that a metallic material and / or metallic alloy for use with the first and second portions 20 , 30 may be especially suitable for many applications . however , the scope of the clamp 10 is not so limited . having described the preferred embodiments , other features of the clamp 10 and method of use will undoubtedly occur to those versed in the art , as will numerous modifications and alterations in the embodiments as illustrated herein , all of which may be achieved without departing from the spirit and scope of the clamp 10 and / or method of use as disclosed herein . it should be noted that the clamp 10 and method of use are not limited to the specific embodiments pictured and described herein , but are intended to apply to all similar apparatuses and methods for verifying that a specific force has been achieved and / or maintained . modifications and alterations from the described embodiments will occur to those skilled in the art without departure from the spirit and scope of the clamp 10 and / or method of use .