Tuesday, March 7, 2017

ZigBee devices - Overview

One of the most popular technologies for wireless smart home communication is ZigBee, Z-Wave being its closest competitor. Both are several generations ahead in features compared to the classic radio based wireless remote control devices that operate e.g. on the 433 MHz radio band.

ZigBee offers a robust communication channel between the devices so that each message can be either delivered successfully or the failure to do so is detected and reacted upon. Another great advantage is the mesh networking capability where each mains powered device propagates and routes the messages to extend the range of the Zigbee network.

ZigBee radio operates with low power consumption which enables the devices to be running on batteries. The radio communication is encrypted to secure your home from hackers or from unintentional controlling.

Cozify & ZigBee

We at Cozify have had good experiences with ZigBee devices in general. All devices are tested thoroughly before official support is announced. Recommendations are only given to devices that are proven to work reliably.

Here are our top-3 ZigBee device recommendations of March 2017:

Philips Hue Lights

Philips Hue lights are stylish and most reliable wireless lights we’ve met so far. Available as bulbs, table tops, wall/ceiling lamps and led strips.

Philips Hue Motion

Affordable, reliable and stylish motion detector, that also comes with an in-built temperature and daylight sensor.

Osram Lightify Plug

Reliable, simple to use power plug.


Before moving into solving problems and issues, it is important to emphasize the easiness of installation and use, and most often design of modern ZigBee devices. In most cases, ZigBee devices are reliable. However, like with everything where software is involved, we sometimes face problems and need a few useful tips to recover.
  1. Once taken into use, Zigbee devices are rather reliable. But in case issues are faces, first thing is to check, and if needed, replace the battery. 
  2. This is simple and sounds obvious, but bring the device closer to the hub. If this improves the reliability, then either the distance between the device and the hub is too long, or the signal is blocked by for example a wall.
  3. Always ensure that all your Zigbee devices are on. Sometimes lamp or bulb is switched off, which means the mesh network might get broken. If the lamp which is switched off is crucial node of your mesh network, other devices connected to the hub through these devices, will be unavailable.
  4. Sometimes the Zigbee mesh network needs to be rebuild. Devices don't always route the signal from and to the hub optimal way. To rebuild Zigbee mesh network, turn all your Zigbee devices on, unplug the Cozify Hub, and leave it off 10 to 15 minutes. This is something that might help if newly added devices don't work reliably. Or if issues begin when you change the location of your Zigbee devices.
  5. A bit more advanced way to do troubleshooting is to ensure the Zigbee channel the hub uses is as free of wifi networks as possible. Please check out this article for troubleshooting tips. If channels collide, try changing either the hub or wifi router channel as far from each other as possible. The channel Cozify Hub uses can be changed from the Cozify app (settings). Note, that if you change the Cozify Hub Zigbee channel from the app, you must re-pair all your Zigbee devices.

Security of the technology 

Even with encryption all the wireless devices suffer from the fact that the radio signals can be jammed by skillful hackers. Then it is up to the system’s design to decide what happens when a device becomes unreachable; does it make an alarm or just plays “robust” to device failures and ignores them. The security of Zigbee devices in general is good. For the absolute highest level of security (and reliability), we suggest installing wired sensors, for example FutureNow relay units, for places that are prone to attract skilled burglars. For the rest of us, the wireless sensors are great for keeping the home secure from unwanted visitors.

ZigBee vs Z-Wave comparison

Although very similar, there are a few differences between the ZigBee and Z-Wave technologies. The prices have come down a lot over the past few years on both device families, and they will continue to drop, but still the Z-wave devices are a bit more expensive. For the money, the end users have enjoyed a better interoperability between the Z-wave certified devices. ZigBee is an open standard and the increased competition has had an impact on the pricing.

ZigBee uses the same radio channel as WiFi and can therefore potentially cause interference. Z-Wave uses unlicensed radio bands that are different in EU and USA due to their regulations. That’s why the end users' needs to select the correct version of their devices. On paper Z-wave has a slightly longer range and ZigBee has a higher data rate, but in real-life these differences are not noticeable.

Both protocols have evolved during the past years to be closer to each other in feature wise. In the end, it boils down to the support available in the selected smart home system. At this very moment, the Cozify Hub supports ZigBee out of the box and the support for the Z-Wave is coming soon. The hub has already all the needed hardware inside, so only a software update is needed for all the existing Cozify users to begin using Z-Wave devices, once it is available.

Read more about Cozify Hub and supported devices from our home page, www.cozify.fi

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