Abstract: An electric indicator that includes an indicating light mounted in a small case containing electronic circuitry, a numerical keyboard, and a battery, the case being attached to a door or door frame, to show the returning user of the indicator whether or not the door has been opened since the indicator was last enabled by the user, typically by entering a secret sequence of numbers into the keyboard. An auxiliary input jack, for electrical connection to other doors and windows, is provided so that the indicator can indicate whether any of several doors and windows has been opened. An auxiliary output jack is provided for a remote indicating light, usually inserted into the peephole existing in many front doors so that the indicator light may be seen from the outside before opening the door. The same output jack may be used for triggering separate audible alarm devices. The indicator is easily adapted for use with drawers, bins, or windows if so desired.