House Alarm
A low cost house alarm system can be designed with DIO-1HT and several DIO-220. All DIO devices use the simplest MQTT/WiFi method. Messages are sent to the MQTT broker (public EMQX broker) in the Internet and are relayed by the MQTT broker (EMQX) and received by the APP in the smart phone or Tablet. Each DIO devices can also trigger LINE messages to indicate DI (Digital Input) status changes to the smart phone or Tablet. This system will be low cost because no server is required in this approach. Each DIO devices is independent of one another, it is simple to add additional new DIO device in the system.
This house alarm system is used to monitor doors, windows, PIR, and CO/Smoke detector. The system will be extensible, so it can monitor many other kinds of sensors. You can customize it for your own needs. In the figure, one DIO-1HT and 3 DIO-220 are used to monitor front door, back door, windows, PIR and CO detector.
Sensors
Normally Closed (NC) door/window magnet is used. Whenever a door or window opens, an alarm message can be generated. Door/window magnets have 2 components – one which mounts to the door/window and the other which mounts right next to it on the door or window frame. The component on the door/window has a magnet inside of it, and the other component has a switch. When the magnet is near the switch, a “normally closed” switch is in the closed or “on” state. If the magnet is more than an inch or so from the switch, the switch opens.
Other sensors/detectora,i.e., Emergency Button, CO detector, Smoke detector and PIR, are configured in NC (Normally Closed) state. NC sensors have some desirable properties. One can daisy chain door and window magnets in series with one single DI input. When any one magnet in the chain opens, it will generate alarm.
Another useful property is cutting wires will cause alarms, since a cut creates an open in the magnet/switch circuit. If a bad guy tries to defeat your system by cutting wires, you’ll get an alarm.
The Smart phone recieves the MQTT messages and uses the APP (MQTT Panel) to diplay the received temprature and humidity as shown in the red box. Each DIO devices can also trigger LINE messages to indicate DI (Digital Input) status changes to the smart phone.
