Zigbee
Zigbee is a wireless communication standard that extends the IEEE 802.15.4 standard, it uses 2 different frequencies (2.4GHz, 869-915MHz), and is very similar to Z-Wave.
Last updated
Zigbee is a wireless communication standard that extends the IEEE 802.15.4 standard, it uses 2 different frequencies (2.4GHz, 869-915MHz), and is very similar to Z-Wave.
Last updated
Before you can get started developing Zigbee apps for Homey, a good place to start is with the basic Zigbee concepts and terminology. We will explain everything you need to know to get started here.
You can view a working example of a Homey App that uses Zigbee at: https://github.com/athombv/com.ikea.tradfri-example
A Zigbee device is made up of one or more endpoints, these are collections of clusters. A cluster is essentially a capability of a Zigbee device.
A cluster can be implemented in two ways:
As server
As client
From the Zigbee Cluster Specification: "Typically, the entity that stores the attributes of a cluster is referred to as the server of that cluster and an entity that affects or manipulates those attributes is referred to as the client of that cluster." More information on this can be found in the Zigbee Cluster Specification section 2.2.2.
Every cluster supports a set of commands and attributes. Attributes are properties of the cluster which can be read, written to and reported to any other bound node. An example would be the "current level" attribute implemented by the "level control" cluster, it represents the value of the current level of the device. The cluster may also support commands which are used to perform actions. An example would be the "move to level" command implemented by the "level control" cluster which makes the cluster change its current level to the level set by the command.
Commands can be sent in two directions:
from client to server
from server to client
The first is probably the most common direction, for example when sending a command from Homey (the client) to a bulb (the server) using the "onOff" cluster and the "toggle" command. The second is when a node (the server) sends a command to Homey (the client), for example a remote which sends the "toggle" command from the "onOff" cluster to Homey to indicate that the toggle button was pressed.
A cluster can report attributes, this means it will send a message to any bound node whenever the value of the attribute changes. Not all attributes are reportable, check the Zigbee Cluster Specification for the specifics of each attribute. In order to make a cluster report an attribute, a binding must be created between the reporting and receiving node.
The difference between server and client clusters is important for the following reason. Nodes can be receivers of commands (i.e. servers), or senders of commands (i.e. clients), and sometimes both. Receiving commands from a node most often requires a binding to be made from the controller (in this case Homey) to the cluster on the node, as well as an implementation of BoundCluster to receive and handle the incoming commands in your app. For more information on implementing a BoundCluster check out the API section.
Zigbee allows another way of inter-node communication which is called groups. This concept can be compared to association groups in Z-Wave. It allows nodes to listen to broadcast messages from other nodes. For example, a remote control which broadcasts its commands to a set of light bulbs. The light bulbs would need to be in the same group as the remote is broadcasting on in order to be controlled with the remote. In order to group devices together the Find and Bind procedure can be used, often this means holding the controlling device close to the receiving device and initiating a commissioning process (how to initiate this process differs from device to device, check the device's manual for these instructions).
By default, Homey listens to all group broadcast communication on its network. Therefore, it does not have to be added to a node's group using Find and Bind in order to receive its commands. This makes it very easy to implement functionality based on group communication in your app.
There are a couple of different types of Zigbee devices:
Routers: these are nodes on the network that are capable of routing messages between devices. Usually these are the non-battery powered devices. These extend the range of the Zigbee mesh network.
End Devices: these are nodes on the network that are not capable of routing messages between devices. Usually these are battery powered devices. These do not extend the range of the Zigbee mesh network.
An important concept in Zigbee is Sleepy End Device (SED). SEDs are End Devices which are asleep most of the time, they only wake up to poll their parent (the Router they are paired to) for new messages every once in a while. A Router keeps track of a couple of messages targeted at the SED while it is asleep, so that the SED can retrieve these messages from the Router when it awakens.
When communicating with SEDs it is important to consider the possibility that it may not respond any time soon, or not at all. Most devices remain awake for a short amount of time directly after pairing, this is therefore the only time you can reliably communicate with the node. Additionally, since the Router has to store the messages for the SED, and the SED wakes up on a variable interval and fetches a single message every time, it is advised to only perform one request at a time for the most reliable communication.
A SED can be identified by the "Receive When Idle" flag in the nodes table in the Zigbee developer tools or programmatically as a property of ZigBeeNode.
The full Zigbee Cluster Specification can be found at Zigbee Cluster Specification (PDF). This contains all information on clusters, commands and attributes you would need to create a driver for a Zigbee device.
The first step in creating a Zigbee driver is to retrieve the following properties of the device:
manufacturerName
productId
These can both be found by pairing the device as Basic Zigbee Device to Homey. Pairing is completely handled by Homey, similar to Z-Wave drivers and in contrast to other types of drivers, you don't have to implement your own pairing views. After pairing check the device settings or go to the Zigbee developer tools and take a look at the nodes table where you can find the manufacturerName and productId.
The second step is finding out how the endpoints and clusters are structured on the device. In order to retrieve this information, interview the device from the Zigbee developer tools.
For Sleepy End Devices this interview might take a while. After it finishes it will provide the required information.
After retrieving the manufacturerName, productId and endpoint definitions, the driver's manifest can be created. This is where is defined that this driver is for a Zigbee device, for which Zigbee device specifically (hence the manufacturerName and productId), and what the endpoints and clusters of this Zigbee device are (hence the endpoint definitions).
This information is added to the zigbee object to the driver's manifest.
The zigbee object contains the following properties:
manufacturerName: This is the manufacturer id which is needed to identify the device.
productId: This is the product id which is needed to identify the device. It is possible to add multiple product ids if the driver targets a couple of very similar devices with different product ids.
endpoints: This is the endpoint definition for the device. Only the endpoints and clusters listed here will be available on the ZCLNode instance (see the documentation on homey-zigbeedriver and zigbee-clusters in below in the API section). The keys of the endpoints object refer to the endpoint id of the node.
clusters: This lists the cluster ids we want to implement as client. This means, the clusters we want to send commands to, or read attributes from, on the remote node.
bindings: This lists the cluster ids we want to implement as server. This means, the clusters we want to be able to receive commands on from a remote node. For each entry in bindings a bind request will be made to the remote node during pairing. In case you want to implement attribute reporting for a specific cluster, add the cluster id here and the required binding will be made during pairing.
In order to create a Zigbee driver a Homey App needs the following dependencies:
You can install these dependencies by running:
Note that zigbee-clusters is a peerDependency of homey-zigbeedriver. This means that homey-zigbeedriver depends on zigbee-clusters being installed with a compatible version.
Finally, the driver needs to be created. Most of the time we can suffice with only /drivers/my_driver/device.js. Please refer to the Drivers guide for more information on this topic.
The easiest way to implement a Zigbee driver is to use homey-zigbeedriver, which is a library we've created which does a lot of the heavy lifting for Zigbee apps. Take a look at the API section for the specifics of this library. Below, a number of basic implementations of various aspects of a Zigbee driver is demonstrated based on homey-zigbeedriver.
Avoid initiating communication with the node in the onInit or onNodeInit phases. Zigbee may not be ready during the initialization of the device, leading to undesirable consequences. Communicating with the node in onInit or onNodeInit can result in queuing numerous requests when the app is started, potentially causing performance bottlenecks.
If communication with the node is attempted in onInit or onNodeInit without catching the request promise, the device may become unavailable, accompanied by an error message indicating that Zigbee was not ready. This is true for versions up to homey-zigbeedriver@2.1.3. While versions 2.1.4 and newer prevent the device from becoming unavailable, there is a risk that the onInit or onNodeInit may not complete as expected.
If there's a genuine need to request data in the onInit or onNodeInit phases, it's important to handle the request promise appropriately. Failing to catch the promise may lead to unforeseen issues. Below is a recommended approach:
In some cases, you might want to perform certain actions only the first time onInit or onNodeInit is called, right after adding the device to Homey. You can achieve this using ZigbeeDevice.isFirstInit() from homey-zigbeedriver. Here's an example:
When developing a Zigbee driver, it can be very useful to see all Zigbee communication between Homey and the Zigbee node. Debug logging for this can be enabled very easily as follows.
It is not recommended to keep this debug logging enabled when publishing your app.
Example logging of a received attribute report frame:
The zclNode is an instance of ZCLNode as exported by zigbee-clusters (check the API section for more information on this library). It can be used to directly communicate with the node using the Zigbee Cluster Library (ZCL).
Using homey-zigbeedriver it is very easy to map Homey's capabilities to Zigbee clusters. The library contains a set of system capabilities, which are basically very common mappings between capabilities and clusters. It is possible to extend these system capabilities when registering them, for more information take a look at the homey-zigbeedriver documentation and API section.
As described above, nodes can report attribute changes to any other bound node. This often requires a binding to be made to the node that should report. This can be done using the driver's manifest bindings property. After that, the attribute reporting must be configured on the node's cluster. The example below demonstrates two ways of configuring attribute reporting:
Directly configuring the attribute reporting.
Configuring the attribute reporting in combination with mapping it to a capability.
For more information on configuring attribute reporting check ZigBeeDevice#configureAttributeReporting.
In order to act on incoming commands from bindings or groups it is necessary to implement a BoundCluster (this is exported by zigbee-clusters):
For more information on implementing a bound cluster checkout the zigbee-clusters documentation on Implementing a bound cluster.
It is possible to implement custom clusters, these are often manufacturer specific implementations of existing clusters. This is too in-depth to cover here, but is documented in Implementing a cluster and Implementing a custom cluster.
This feature is available as of Homey v5.0.0 and requires homey-zigbeedriver@1.6.0 or higher. Additionally,
Drivermust extendZigBeeDriveras exported by homey-zigbeedriver.
In some cases a single physical Zigbee device should be represented as multiple devices in Homey after pairing. Most physical Zigbee devices should be represented by a single Homey device for the best user experience. However, for some devices, like a socket with multiple outputs, the user experience is improved when there are multiple Homey devices representing it. Sub devices enable you to automatically create multiple devices in Homey after pairing a single physical Zigbee device. In order for Homey to create multiple instances of Device you need to define a devices property in your Zigbee driver's manifest. The keys of this object represent a unique sub device ID which will be added to the device data object as subDeviceId. For example, based on the manifest below:
This can be used in device.js to discern between the root device, and the various sub devices.
The sub device object can contain any property the root device can contain, e.g. class, name, and capabilties. Properties that are omitted in the sub device will be copied over from the root device. If the sub device should not get the same settings as the root device, make sure to add the settings: [] property to the sub device, as demonstrated below.
Each Device will have access to the same ZCLNode instance and can access all endpoints. By default, for each sub device a device instance, as exported in device.js, will be created. If the implementation of device.js is quite different between sub devices you can use Driver#onMapDeviceClass() to properly separate the logic for the root and sub devices by implementing multiple Device classes.
The Zigbee Cluster Library specifies three IAS clusters: IAS Zone, IAS ACE and IAS WD. It is required for devices that support these clusters to perform a IAS Zone Enrollment step after joining a network (see Section 8.2.2.2.3 of the ZCL specification). Homey Pro (as of v8.1.1) and Homey Cloud will ensure that a device that supports the IAS Zone cluster will receive a Write Attribute command to set the IAS_CIE_Address attribute with Homey's IEEE address (this is step 2 of the three available commissioning methods described in Section 8.2.2.2.3 of the ZCL specification).
Homey Apps are then responsible to further complete the commissioning process supported by the device. Usually this means listening for a Zone Enroll Request and replying with a Zone Enroll Response. To implement this in a driver, a few things are important.
Add cluster id 1280 (IAS Zone) to the "clusters" array (in driver.compose.json) for the endpoint that should perform the zone enrollment.
Make sure to use zigbee-clusters@1.7.0 or higher.
See the following example to learn how to listen for zone enroll requests and respond with a zone enroll response in device.js
During pairing Homey sends a Write Attribute command to set the IAS_CIE_Address attribute on the joining node. Since this happens before the driver in your app is initialized, it might happen that your driver never receives the Zone Enroll Request. This depends on how quickly the node sends the request after receiving the Write Attribute command from Homey. To overcome this, the driver could send a Zone Enroll Response when initializing regardless of having received the Zone Enroll Request.
There are three Zigbee API levels which all build on top of each other with increasing complexity to interact with Zigbee devices on Homey:
In general it is likely you will only need homey-zigbeedriver, and possibly zigbee-clusters if you want to do some more advanced things. The Zigbee API is what zigbee-clusters is built on. It is not advised to use this API directly, but it is there in case you need it.
This library is developed by Athom to make it easier to create a driver for Zigbee devices.
It exposes classes which can be extended in your app and other useful functionality. The most important class is ZigBeeDevice. This class handles getting a ZigBeeNode and uses zigbee-clusters to extend the ZigBeeNode with Zigbee Cluster Library (ZCL) functionality. Doing this enables a developer to directly communicate with the ZigBeeNode using ZCL very easily. The basic usage is demonstrated below, for more in-depth information take a look at the homey-zigbeedriver documentation or the source code on GitHub.
Note: for Zigbee light devices (e.g. bulbs and spots) we created ZigBeeLightDevice, this class can be extended in your driver and will by default handle all light related functionality.
This is the library used by homey-zigbeedriver to expose the Zigbee Cluster Library (ZCL) functionality. It implements all the clusters that are accessible through zclNode in lib/clusters. It is very easy to add new clusters, or add attributes or commands to an existing cluster, merely by changing the definition in one of the cluster files (e.g. the onOff cluster). If you are interested in how this library works, take a look at the Zigbee Cluster Specification (PDF). The basic usage of this library is demonstrated below, note that it is usually better to use ZigBeeDevice exported by homey-zigbeedriver instead.
There are a few cases where you need to interact with zigbee-clusters in your app.
In order to inform homey-zigbeedriver about which cluster we are targeting we need to import the cluster specification from zigbee-clusters as demonstrated below.
This ensures the cluster to be registered will be available in zigbee-clusters.
To add or improve clusters for zigbee-clusters , changes can be made to the cluster definition in lib/clusters. For more information on how to do this, check out Implementing a cluster.
As mentioned in the introduction, in order to receive commands from a node, a binding must be made to the respective cluster. This can be done by listing the cluster id in the bindings array in the driver's manifest. Please refer to Implementing a bound cluster for more information on how to create a BoundCluster in your driver.
Zigbee device manufacturers are allowed to implement custom clusters for their devices. In order to use such a custom cluster in your driver you need to extend an existing cluster with the custom behaviour. Check out Implementing a custom cluster on how to do this exactly.
The Zigbee API can be used for directly communicating with a ZigBeeNode if needed. In general it is advised not to use this API and take a look at zigbee-clusters and homey-zigbeedriver which are libraries built on top of the Zigbee API which do most of the heavy lifting and make it even easier to develop Zigbee apps for Homey.
In the unexpected case that you do want to access the Zigbee API take a look below for a basic example.
First, the ZigBeeNode must be retrieved from ManagerZigBee.
Next, we can use the Zigbee API to directly communicate with the ZigBeeNode using ZigBeeNode#sendFrame() and ZigBeeNode#handleFrame()
Important: override the handleFrame method on ZigBeeNode, this method is called when a frame is received and if it is not overridden it will throw.
