ZigBee is a low cost wireless system for high level communication between low power radio devices. It is based on the IEEE 802.15 standard.
Although it is low power, ZigBee devices can transmit data over greater distances by passing the commands through intermediate devices, creating a mesh network. No centralised control unit is needed for data to be sent to all devices on a network.
The ZigBee system is used in applications where reduced data throughput, long battery life and a secure network is needed. It is best suited for use in areas where the data needed is intermitent, for instance, wireless light switches which only need to use a short range and a low amount of data to be transmitted.
ZigBee was conceived in 1998, standardized in 2003 and revised in 2006. The name refers to the waggle dance of honey bees after their return to the beehive.
Types Of Devices
There are two types of devices in a ZigBee, a router device and an end device.
A router device is one that has permanent power. For instance, a controller mounted inside a luminaire. These devices can always send and receive information, allowing for communication through the device.
An end device is one that only transmits information, such as a wall switch. This extends the battery life of the switch by only using power when it is needed. An end device will only be able to receive information when it is in commissioning mode.
The transmission range of a ZigBee device is around 10m, so the location of installed units can be important when specifying a ZigBee system to ensure complete device coverage.
In the example below, all the luminaires can be switched on by the passive infrared detector. They can be dimmed up and down from the switch. The infrared detectors are equipped with daylight regulation, the fittings nearest the window can be set to fade up and down in relation to the reflected light from the working plane.