Z-Wave is a wireless automation technology that is used primarily for home automation. It is one of the newest kinds of wireless technology that smart devices use to communicate with each other.
Z-wave uses low-power radio waves that travel through walls, furniture, and floors; this means that we don’t have to rip-up floors and carpets to add new wiring.
We can think of Z-wave as a category of Wi-Fi or Bluetooth, but it possesses a few special qualities which can be considered as major advantages for home automation.
Features such as status updates, two-communication, and mesh networking are combined to ensure resiliency and reliability in our Home Automation system. This means we don’t have to wonder whether the light in our garage is turned off when we close our door.
Z-Wave enable us to easily create a modern smart home, giving us control over multimedia, lights, appliances, heating, and security at the touch of a button.
Let’s look at some of the technical characteristics of the Z-wave technology:
Technical characteristics
1. Topology, network setup, and routing
When a device is connected to the Z-wave network, it uses a source-routed mesh architecture. Z-Wave itself uses a source-routed mesh network architecture.
The mesh networks are also called wireless ad hoc networks. In mesh networks, devices use the wireless channel to send control messages which are then transmitted by neighbouring devices in a wave-like fashion.
Devices can communicate with one another by using interjacent nodes. These interjacent nodes will actively route around and find a way around radio dead spots or household obstacles that might occur in the multipath environment of a house.
Let’s assume a message was sent from node A to node C; it will be delivered successfully even if the two nodes are not within range. As a result of a node B that can communicate with nodes A and C.
This means that if the preferred route is not available, the message originator will attempt other routes until a path is found to its destination.
Therefore, a Z-Wave network can reach more distance than the radio range of a single unit. However, with several of these hops, a small delay may be introduced between the desired result and the control command.
The simplest network is the primary controller and a single controllable device. Other devices can be added at any time, as can secondary controllers, including wall-switch controllers, key-fob controllers, traditional hand-held controllers, and PC applications.
All these additional devices are designed for the management and control of a Z-Wave network.
A Z-Wave network can contain up to 232 devices, with the option of linking networks if more devices are needed. To control a device via the Z-wave, it must be “included” to the Z-wave network.
This process (also known as “adding” and “pairing”) is usually achieved by pressing a sequence of buttons on the device added to the network and on the controller.
This progression only needs to be performed once, and then the device will always be recognized by the controller.
Removing devices from the Z-Wave network is done by a similar procedure. The controller learns the signal power between the devices during the pairing process.
Therefore the architecture expects the devices to be in their deliberate final location before they are added to the system.
Normally, the controller has a small internal battery backup, which allows it to be unplugged temporarily and then taken to the location of a new device for pairing. The controller is then returned to its expected location and reconnected.
The Z-Wave chip is built for battery-powered devices and usually remains in a power-saving mode to consume less energy, then waking up only to perform its function.
With the Z-Wave mesh networks, all devices in the house bounce wireless signals around the house. Resulting in low power consumption, then allowing devices to work for a long time without us needing to replace their batteries.
2. Hardware
The ZW0500 is the chip for Z-Wave nodes. Also, it is built around an Intel MCS-51 microcontroller with an internal system clock of 32 megahertz.
The radio-frequency (RF) part of the chip contains a GisFSK transceiver for a software-selectable frequency.
It has a power supply of 2.2 – 3.6 volts, and it consumes up to 23mA in transmit mode. Its features include a 100kbps wireless channel, AES-128 encryption, USB VCP support, and concurrent listening on multiple channels.
3. Security
Initially, Z-wave was based on proprietary design, supported by Sigma Designs as its main chip vendor but in 2018, it was acquired by Silicon Labs. Also, in 2014, Mitsumi became a licensed second source for the Z-Wave 500 series chips.
There have been several practicals and academic security researches on home automation systems based on X10 protocols and Zigbee.
Research is still at its starting point to examine the Z-Wave protocol stack layers, requiring the design of related software to intercept Z-Wave communications and a radio packet capture device.
On 17th November 2016, the Z-Wave Alliance proclaimed stronger security standards for devices. The announced security standard is known as Security 2 (or S2), and it provides advanced security for gateways, smart home devices, and hubs.
It mandates new pairing procedures for each device, with unique QR codes or PIN on each device, and shores up encryption standards for transmissions between nodes.
The new layer of authentication is intended to prevent hackers from taking control of poorly-secured or unsecured devices.
According to the Z-Wave Alliance, the new security standard is the most advanced security available on the market for smart home controllers and devices, gateways, and hubs.
4. Radio frequencies
Z-Wave is designed to provide reliable, the low-latency transmission of small data packets at data rates up to 100 kilobits per second. The output is 40 kilobit per second (9.6kbit/s using old chips) and is suitable for sensor and control applications.
Unlike other IEEE 802.11-based wireless LAN systems and Wi-Fi that are designed primarily for high data rates.
The communication distance between two nodes is about 30 meters (and up to 40 meters with 500 series chips). In addition, it has the message ability to hop up to four times between nodes.
This gives enough coverage for most residential houses. Modulation is FSK (frequency-shift keying) with Manchester encoding.
Advantages of Z-Wave
1. Affordability
One big advantage of Z-Wave compared to other traditional smart home solutions, such as KNX, ZigBee, and X10, is its affordability.
This is because the Z-wave installation does not require construction work or a specialist contractor. Also, we can choose to expand our system at any time.
Z-Wave home automation solutions are available and suitable for everyone. They allow us to remotely control not only our flat or home, but also our garage, garden house, or cottage.
2. Wireless signal range
Most wireless technologies usually suffer from interference issues and short-range. Z-wave, unlike other wireless technologies used in our home, does not suffer from interference from phones, microwave ovens, Wi-Fi networks. The Z-Wave frequency used in Europe is 868.42 Megahertz.
The regular range of a Z-Wave signal is 50 meters inside buildings (depending on the materials used, which may decrease the range indoors) and 100 meters out in the open.
Z-Wave is a mesh technology; this means all Z-Wave devices can communicate with one another and send the signal from one Z-Wave device to another. Also, it means the information is routed from the sender to the recipient throughout the Z-Wave network.
In addition, this means that the range of the Z-Wave network increases with the number of connected Z-Wave devices. In short, the more Z-Wave devices there are in our home, the bigger the size and range of the Z-Wave network.
3. Energy efficiency
Some Z-Wave devices, such as motion sensors or thermostats and temperature, are battery-powered. The ability to save power is essential. Z-Wave devices are enhanced for energy efficiency with a typical battery life of twelve months and more.
Equally important is the issue of electromagnetic smog (that is, the discharge of wireless signals and their effect on humans) and the protection of human health.
All Z-Wave devices, for example, thermostats, socket modules, sensors, light dimmers, etc. have very low electromagnetic emissions. For better understanding, this means the emissions are 4,000-times lower than those of a mobile phone.
4. Simple installation
One major advantage of Z-wave is its easy and simple installation. To set up an electronic Z-Wave device, such as a thermostat or light switch, you just need to switch it on and add it to the Z-Wave network.
After reading it to the Z-Wave network, you can immediately start controlling it from your PC, mobile phone, or tablet.
Installing most Z-Wave devices is as simple as replacing a light bulb, just anyone can do it. Naturally, some devices require professional installation because it involves the modification of an electric installation, for example, a switching relay (module installed under plaster).
5. Security and reliability
The communication between all Z-Wave devices is secure and reliable because they communicate with one another wirelessly.
Data transfer security is of vital importance, especially when one of the main attributes of a smart home is the protection of property and people. Z-Wave uses the same information security standard (encryption) as most internet banking applications.
The Z-Wave standard requires that every communication is acknowledged (ACK). That means if, for example, a PIR motion sensor detects sends information to the security system, anytime it detects movement in the room, and then confirms receipt of the information.
6. Interoperability and availability of devices
Currently, Z-Wave is the most popularly used home automation technology in the world. Presently, there are over 900 products offered by more than 250 manufacturers around the world. Also, all Z-Wave devices are fully interoperable.
This means that you are not tied to a single manufacturer when implementing a home automation solution. So your investment is better guarded compared to using a proprietary solution from a single manufacturer.
7. Flexibility and modularity
Since Z-Wave is a wireless technology, its installation doesn’t require any additional cabling. It is really easy to create a smart home; also, you can make changes at any time because no construction work is needed to install Z-Wave devices.
Also, that means that should you decide to install lighting control today, in a month, you can continue with motion sensor installation or heating control.
For more information check out the official site.
