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224 HANDBOOK OF ELECTRONIC ASSISTIVE TECHNOLOGY

therefore unaffected by other wireless technologies. The protocol is contained in a pro-
prietary chip and can be obtained as part of an OEM developer’s kit if the purchaser
joins the Z-Wave Alliance. The Z-Wave Alliance, which is responsible for issues such
as interoperability, was formed in 2005. It is claimed that there are currently over 1700
Z-Wave products available.

Zigbee
Zigbee is a low-cost, low-power, wireless mesh networking standard IEEE 802.15.4 operat-
ing in the 2.4 GHz range, and was developed specifically to be cheaper and simpler than
other Wireless Personal Area Networks (WPANs) such as Bluetooth. It is intended for inter-
mittent data transmission at low rates over relatively short distances from ‘sensors’ and
uses either mesh networking or star or tree configurations to achieve the required trans-
mission. A network requires one coordinator device to manage the network and in a star
network this must be the central node. It is ideally suited to be embedded in everyday
devices for home automation and medical device data collection. The Zigbee Alliance pro-
motes the platform as a natural choice for the Internet of Things (IoT) and has recently
underpinned its commitment in this area with the unveiling of Dotdot in January 2017,
which is proposed as a universal language for IoT devices. 3

EnOcean
EnOcean is a patented wireless energy harvesting technology for use in areas such as
home automation. The devices combine microenergy converters with ultralow power
electronics to create devices that are powered by their own operation and therefore do not
require an external power supply. This makes it ideally suited to retrofitting applications.
The EnOcean wireless standard was ratified as the international standard / 14543-3-10 in
March 2012, which covers OSI standard layers 1–3.

Bluetooth

Bluetooth is another WPAN standard, operating in the 2.4 GHz range using a method
called frequency-hopping spread spectrum. It is designed to operate at a distance of
between 10 and 100 m, although it typically operates at 10 m or less. Its development
began in 1989 at Ericsson Mobile under the title ‘short-link’ radio technology, to allow
communication with wireless headsets and was named Bluetooth in 1997 while it
was being repurposed by Intel for communication between mobile phones and com-
puters. A master device can communicate with up to seven devices within an ad-hoc
Bluetooth network, called a piconet, within which master/slave roles can be switched.
Bluetooth was standardised as IEEE 802.15.1. It has undergone continuous evolution,
with Bluetooth 4.0 also known as Bluetooth Smart incorporating Bluetooth LE (low

3 http://www.zigbee.org/the-zigbee-alliance-to-unveil-universal-language-for-the-iot-from-ces-2017-
making-it-possible-for-smart-objects-to-work-together-on-any-network/.