The ornamental design for an electronicdoorknob, as shown and described.
FIG. 1 is a front and top perspective view of an electronic door knob, showing my design.
FIG. 2 is a rear and bottom perspective view thereof.
FIG. 3 is a front elevation view thereof.
FIG. 4 is a rear elevation view thereof.
FIG. 5 is a left side elevation thereof.
FIG. 6 is a right side elevation thereof.
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The broken lines shown in the drawings are included for the purpose of illustrating portions of the electronic door knob for environmental structure that form no part of the claimed design.