Abstract: An interior door knob for conventional lockable door latches includes a hollow knob with a cylindrical neck having conventional means for engaging and rotating the latch spindle to mechanically move the door bolt and an actuator mechanically engaging the locking mechanism of the door latch and extending through the cylindrical neck into the housing and being movable between a first and a second position. A battery, an acoustic/visual indicating means and a normally-open microswitch electrically connected in series are mounted in a component module received within the knob housing. The microswitch switches responsive to the position of the actuator for indicating when the locking mechanism of the door latch is not locked.