Zigbee
A low-power mesh radio for sensors that need to run for months on a coin cell, not a high-bandwidth link — battery-powered nodes hopping data through mains-powered ones toward your gateway device.
What Zigbee actually is
Zigbee trades bandwidth for battery life and range-through-repetition. It's built on the IEEE 802.15.4 radio layer, same physical layer family as Thread, but adds its own mesh networking and application layer on top. The headline feature is the mesh itself: mains-powered nodes act as routers and relay traffic for battery-powered nodes that are out of direct range of the coordinator, and the mesh reroutes automatically if a router drops off line. That's why a Zigbee network tends to get more reliable as you add more powered devices to it, not less.
It's a poor fit for anything that needs continuous throughput — video, audio, high-rate telemetry — but a very good fit for occasional, small messages: a door sensor reporting open/closed, a temperature reading every few minutes, a button press. Those workloads are exactly where a coin-cell battery can last a year or more, because the radio spends almost all its time asleep.
Coordinator
Exactly one per network. Forms the network and holds its security keys. This is usually the USB dongle plugged into your gateway device.
Router
Mains-powered, always listening. Relays messages for other nodes and extends the mesh's physical reach.
End device
Battery-powered, mostly asleep. Talks only to its parent router or the coordinator, never relays for others.
How this fits into a General Infinity fleet
Zigbee devices don't run your deployment — a bare sensor has no CPU to speak of and can't run the General CLI. The pattern is a gateway: one device in the fleet (typically a Pi) carries a Zigbee coordinator dongle over USB, and your deployed code on that device is what actually joins the network, receives sensor reports, and does something with them — write to your database, forward to another service, trigger an action. General Infinity's role is the same as always: get that gateway code onto the device and keep it running. It has no visibility into the Zigbee network itself, only into the process you wrote to bridge it.
Things that bite people
- Wi-Fi channel overlap. Zigbee and 2.4 GHz Wi-Fi share spectrum. If your gateway also runs busy Wi-Fi, pick a Zigbee channel that doesn't overlap your Wi-Fi channel, or you'll see flaky drops that look like a hardware fault.
- Coordinator placement matters more than router count. A coordinator buried behind a metal enclosure or in a cabinet full of other radios will struggle no matter how many routers you add.
- Re-pairing after a coordinator swap. The coordinator holds the network's security keys — replace the dongle without backing up its network state, and every device on the mesh needs to be re-paired.