Most of the night vision app does not function well with the mobile phones and it creates some malefactors and threaten the mobile security factors. In order to replace the phone camera with the night vision system without using any kind of apps, first thing is to make a trial over the old mobile phones by implementing the night vision system.
After choosing the old mobile phone, open up the back cover of the phone and trace out the camera outline with the transparent disc affixed over the lens. Gently, remove and securely replace it with the IR LED to the phone holder. Tightly fit the phone cover, to turn on the camera for tracing out the objects in the deep dark conditions.