Zigbee is a low-power, low-rate wireless technology designed for sensor networks. Its strength is meshing (mesh): each node relays the messages of the others, which extends the reach of the network without extending the reach of any single transmitter.
How does it work?
It turns up mostly in home automation and in networks of numerous objects. The network does not organise itself by magic: it needs a coordinator (a home automation hub, a USB dongle) to found it and administer it. The mesh then makes the network robust. If a node goes down, messages route around it. That robustness is paid for by an organisation more complex than a plain star. The data rate, deliberately low, is enough for sensors and commands, and it serves the low power draw.
See also
- Wireless technologies — hub: where Zigbee sits among the others
- XBee — off-the-shelf modules, often implementing Zigbee
- LoRa — the alternative for very long range