Installation and runtime

OpenHAB requires a JVM and can be deployed on servers running various operating systems, a dedicated Raspberry Pi instance, or some network-attached storage systems.^[6][7] The required bindings can be added at runtime via OSGi. OpenHAB supports a number of persistence backends for storing and querying the smart home data, including relational and time series databases. By default openHAB uses rrd4j for persistence.^[8]

Discovery and configuration

After installation, openHAB scans the local network and discovers devices that can be included in the smart home solution.^[9] Users can provide credentials and meaningful device names via an administration user interface.

Things and Items

Since major version 2 of openHAB the connections to physical devices is split in 2 levels. "Things" are the interface elements to a specific physical device (e.g. an interface to a home automation network like KNX, Z-Wave or Zigbee). Within these things, one or more "Items" can then be defined or discovered. These "Items" correspond to one specific component like a relay controlling a light, the desired temperature of a heating system or a dimmer percentage.

Sitemaps

Sitemaps allow the user to determine how the devices in the smart home are arranged. A sitemap groups devices by floor and room and determines how they are visualized and controlled. The following example illustrates what a typical sitemap definition might look like:

sitemap demo label="My home automation" {
    Frame label="Date" {
        Text item=Date
    }
    Frame label="Demo" {
        Switch item=Lights icon="light"
        Text item=LR_Temperature label="Livingroom [%.1f °C]"
        Group item=Heating
        Text item=LR_Multimedia_Summary label="Multimedia [%s]" icon="video" {
            Selection item=LR_TV_Channel mappings=[0="off", 1="DasErste", 2="BBC One", 3="Cartoon Network"]
            Slider item=LR_TV_Volume
        }
    }
}

User interface

Once the system is configured, openHAB users can view data and perform actions using a number of user interfaces. These include a browser based interface as well as apps for Android, Windows 10, and iOS.^[10][11][12] All of these UIs are defined by the sitemap mechanism.

Rules

An event, condition, action rule-based system is used to automate the smart home. The following example turns off a light once the sun rises at the configured location.

rule "Start wake up light on sunrise"
when
    Channel "astro:sun:home:rise#event" triggered
then
    switch(receivedEvent.getEvent()) {
        case "START": {
            Light.sendCommand(OFF)
        }
    }
end

openHAB Cloud

OpenHAB Cloud is a companion cloud service and backend for openHAB. It provides secure remote access and enables openHAB users to remotely monitor, control and steer their homes through the internet. The openHAB foundation provides a demo system without SLA guarantees.^[13]