Obviously, it was only a matter of time before this happened: Robotics scientists in South Korea have designed a prototype of a prison guard robot and have now begun testing it. The RoboGuard is equipped with multiple cameras as well as "software designed to gauge a prisoner's emotional state" in order to prevent suicide and fights.
Perhaps what they need is something like the Salvatio Romae, the elaborate alarm system attributed to Vergil by Alexander Neckam in De naturis rerum (On the natures of things), ca. 1190s. According to Neckam, Vergil had made a building, inside which stood a number of statues, one for each province of the Roman Empire. Another statue stood on top of the building. If any of the provinces threatened revolt or came under outside attack, the corresponding statue would ring a bell, and the statue on the roof would swivel around and point in the direction of the threat.