There are sensors all over the island that can pick up your movement in Deathloop. If you remain in a sensor’s light for too long, an alarm will sound off, and enemies will be alerted to your position. Luckily, you can use the hackamajig to disrupt it and essentially turn it off to make it easier to move through an area without enemy forces’ detection.
The sensors will look like a camera, and emit a strange blue light in front of them, constantly scanning an area. If you step in the light for too long without running away, an alarm will sound off. All you have to do is be in range of the sensor, have your hackamajig in one hand, and then hold down the button to activate the device. While playing on a PlayStation, it will be the L1 button. You’ll have to remain in range with the hackamajig clicking off and on until the hack is complete.
Once it is, the blue light will become green, and you’ll be able to pass through the sensor’s lights undetected. Whenever you see one of these sensors, you want to make sure you have your hackamajig out and can quickly takeover the device. Failure to do so can lead to multiple enemies finding your location and swarming you.
From what we’ve seen, the hacked effect will continue to affect the sensor even if you leave an area. You can roam around the same location and not have to constantly rehack the same sensors.