Abstract: A compact, self-contained device for placing inside a package or other enclosure to detect unwanted disposition of its contents. The device includes a sensor for detecting an environmental condition that indicates unwanted disposition of the contents of the package. The device also includes a compact interface for communicating information about unwanted disposition. Environmental conditions indicative of unwanted disposition include an increase in ambient light to indicate the opening of the package, excessive acceleration from dropping of the package, and excessive heat or cold. The user may arm and interrogate the device by modifying the environmental condition perceived by the sensor. For example, a device using a light detecting sensor may be armed by covering and uncovering with a finger. A device using an acceleration detecting sensor may be armed by tapping on a hard surface.