various embodiments are described that relate to a detector . the detector can include a loop functioning at a high frequency that emits a magnetic field . the magnetic field can be retrieved and a comparison can be made between the emitted magnetic field and the retrieved magnetic field . if there is substantially little difference between the emitted and retrieved field , then a determination can be that no object is present . conversely , if there is a substantial difference between the emitted and retrieved field , then the determination can be that an object is present and thus the object is detected . if the object is present , the returned magnetic field can be further analyzed to determine the type of object that is detected .