The Hunger Games (Holo)

In the last book (third movie), Mockingjay, the rebels have a device called a Holo that can project a 3D holographic model of the Capitol. Users can zoom in on streets, and can display "pods" (booby traps) nearby. Unlike the game masters' model of the Arena it can only be used for viewing, not for altering the city, and it is not completely up to date. Katniss's unit use it to navigate successfully through some pods, but it fails to inform them about one, and several people in the unit are killed. Later, Katniss uses the holo's self-destruct function when Finnick is being mauled by monsters and cannot be saved: she throws the holo so that Finnick and the monsters are blown up, thus saving the rest of the unit from the monsters, and putting Finnick's suffering to an end, much as she did with Cato at the end of the first Hunger Games.