We build a small smart home application. We have two sensors which are a temperature sensor and a motion sensor. Also, we consider to have an alarm, a fan and a siren. The temperature sensor is detecting the ambient temperature of the room, while the motion sensor checks if there is any movement in the room. When the temperature goes above a certain value ( for example above 25 degree Cesius) then the alarm goes off and the fan starts to run in its maximum speed. When the temperature goes back under the certain set (below 25 degree Celsius), then the fan should go off and the alarm should stop. Meantime, the motion sensor checks the movement in the room and in case of detecting any movement a siren should start warning. In this example we assume that the sensors and the alarrm are in one room, whereas the fan and the siren are in another room. Therefore, we assume to have a home gateway to transmit information between these two rooms using WiFi. Obviously you need at least two controllers for each room that are communicating to each other via the home gateway to transmit information between these two rooms using WiFi. Obviously you need at least two controllers for each room that are communicating to each other via the home gateway. Figure below shows an example. Components are choosen from Cisco Packet Tracer tool and the code is written in Python for the controllers.