Scanners, also known as Contraband Detectors and Metal Detectors, are implements to The Escapists, giving you 99% Heat when passed through with Contraband in your inventory. They only activate if you walk through them with Contraband on you. If you used as a weapon it will not detect you. If you walk thru on The Escapists 2,Heat will rise to 100%.
A Contraband Pouch and a Durable Contraband Pouch degrade over time, with a Contraband Pouch degrading by 25% every time you walk through a scanner and a Durable Contraband Pouch degrading by 15% every time. Turning off the Generator is much trickier because you need to leave your Cell at night (it needs to be night, otherwise the Tower Guards will shoot you), evade the Guards and escape the main building to reach it. Once you reach the Generator Left-Click it to power it down. Then, get back to your Cell and save.
At night, Contraband Detectors are practically useless because Tower Guards will have gone home and guards will attack you regardless of your heat if you are outside of your cell, so you don't have to worry about them.
Another way to smuggle contraband through is by knocking out an inmate and putting him in/near the detector, putting the contraband in his pockets, walking through, and grabbing your stuff from his body