These Zigbee home automation devices need no batteries or wires

The Zigbee Alliance finally gets to explore the potential of its Green Power spec for doing away with batteries, thanks to help from the developer of a rival home automation system

EnOcean PTM 210 energy-harvesting switch module

This unassuming 40x40mm module is an EnOcean PTM 210 wireless and batteryless light switch, capable of transmitting different codes for long or short presses on each of the four buttons, powered only by the pressure of the user's finger.

Credit: EnOcean

You're probably most familiar with piezoelectricity as the generator of the spark that lights the gas stove, but it's finding a new application in Las Vegas this week: lighting up the living room.

Energy-harvesting controls for home automation have been a thing since at least 2001, when Siemens set up a new company, EnOcean, to commercialize the piezo-powered wireless light switches it had developed. Pushing on the rocker switches generated just enough piezoelectrical energy to broadcast a 128-bit "telegram" to radio modules inside light fixtures, electrical outlets or control hubs.

EnOcean has since added other energy sources to its range, powering environmental sensors with tiny photovoltaic panels and controlling radiator valves by generating energy from the temperature difference between the inside and the outside of the valve.

When Siemens created EnOcean, the wireless protocols of the day required more power than the piezoelectric system could generate, so the company rolled its own, setting up the EnOcean Alliance to promote its use. Now, the company says, over 150 manufacturers sell electrical fittings containing its energy-harvesting and radio technologies.

The system has proven popular with owners of commercial buildings, who like how it allows them to remodel without having to rewire, yet avoids the expense of employing someone to replace the batteries in thousands of light switches every year or two.

Changing the batteries when the light switch won't work isn't such a big deal in the home, which is just as well as the makers of home automation hubs have tended to feature more open or standards-based wireless protocols such as Zwave or Zigbee, which typically require the kind of power that only a battery or an AC adapter can provide.

Attracted by the potential of energy-harvesting systems, though, in late 2012 the Zigbee Alliance added a low-power variant of its protocol, Zigbee Green Power, to its specification. It's taken a while for that move to ripple through the ecosystem, though, as chip makers redesigned their products, first to transmit the new protocol and then to operate on far less power.

Finally, last December, the EnOcean Alliance said it would help companies adapt its energy harvesting systems to transmit Zigbee Green Power messages at 2.4GHz instead of EnOcean telegrams at sub-1GHz frequencies.

That caught the attention of Illumra, which has sold EnOcean-compatible light switches for 10 years.

At the CES show in Las Vegas on Thursday it unveiled its first Self Powered Zigbee Switch, based on EnOcean's piezoelectric module and able to control Zigbee 3.0 devices with support for the Green Power extension. It plans to begin selling the switches later this quarter in a range of colors, so that OEMs can package them with their own decorative faceplates.

At CES, the EnOcean Alliance is also exhibiting alongside the AllSeen Alliance and the Open Interconnect Consortium to break down the barriers between competing communications standards for the Internet of Things. Other members of the EnOcean Alliance are there too, including NodOn with a module that can turn existing wired wall switches into EnOcean transmitters, and batteryless sensor maker Avidsen showing how its products can interface with a self-learning cloud platform from Ubiant to control the home.

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