Always Be Aware of Your Safety at Home If the sensor detects someone opening your window or door, it will promptly send you a push notification. Seeing Who Visited the House You can see what's happening in your house in addition to getting alert notifications when the door is opened if you add a SONOFF camera or an idle smartphone. Made Intelligent in the Process Do you want the door to light up the hallway as soon as you enter? To get started, just connect the SONOFF switch or light to the sensor. installation without the need for tools. uses 3M adhesive on the sensor's underside to facilitate installation.