An elongated hand held sensor is removable from a strap for use. The strap can also be used to form a loop that is attached to another object, such as a handle or other fixture, such as a bedroom furnishing. The sensor may contain an electrode at one end in signal communication with a capacitive measurement circuit on a circuit board in the sensor device housing. The electrode is optionally shaped to have adjacent portions that match the non-planar shape at the distal end of the housing.