Optical window and door contact - opening sensor for Homematic IP This sensor for the Homematic IP system makes it possible to improve the energy efficiency of the heating system and also allows an effective access control. As it functions on the basis of an infrared light barrier, no counter-contact is required on door or window frames. If the sensor detects that a window or an external door is opened, the linked thermostat reduces the heating power and adjusts the room temperature back to the target value after ventilation. The opening status can be tracked at any time via the Homematic IP app. An armed alarm siren that is linked to the contact is triggered when a monitored door or window is opened without authorisation. Features / compatibility - Homematic IP integrates the areas of indoor climate, security, fire and water protection, weather, lighting and shutter control - simply installed, simply extended and simply secure - Detects and transmits the opening status of windows and