Hidden object detector

This disclosure describes a stud sensor configured to locate a stud. The stud sensor includes a housing and a sensor carried by the housing. The sensor includes two or more electrodes. The two or more electrodes are configured to form a substantially circular configuration. The stud sensor further comprises one or more processors carried by the housing. The one or more processors are communicatively coupled with the sensor. The one or more processors are configured by machine-readable instructions to calculate a stud location by measuring a change in capacitance from a fixed capacitance of a wall structure as the stud sensor is moved along a surface of the wall structure; and generate one or more signals to report a result relating to a location of a stud.