ZigBee product flood defies sceptics

Lots of ZigBee products are appearing, but there are still some people who think they can build a better low-power sensor network.

Product announcements are flooding out for ZigBee, a low-power sensor networking standard, but rivals continue to maintain their technologies also have a place.

ZigBee chips are now widely available, including low-power devices designed for long-term use. Around 30 companies will show products on Wednesday at a gathering of the ZigBee Alliance, a 180-strong group of ZigBee supporters--which promises to link up all the devices that other networks leave behind, from light switches to burglar alarms.

"We expect this to be a record Open House given that more than 8,000 interested parties have requested access to the ZigBee specification," said Bob Heile, chairman of the ZigBee Alliance, which is meeting in the Woodfield hotel in Chicago.

ZigBee is a commercial standard, built on top of the IEEE's 802.15.4 standard and using the licence-exempt 2.4GHz waveband, but there are alternatives for low-power networks. "Developers of products and solutions for industry are now choosing from among several wireless technologies," says a report from technology analysts ARC Advisory Group. "Their menu of technology choices consists of IEEE 802.11, IEEE 802.15.4 (either with or without ZigBee), Bluetooth, and even more far off wireless technologies like UWB."

The 802.15.4 standard gives low power consumption needed for long-lived 'fit-and-forget' battery devices, but that still leaves users with the choice "to ZigBee or not to ZigBee?" according to the ARC report, ZigBee in a Nutshell.  The report says that extensions beyond ZigBee may offer more radio-frequency agility, more reliable edge devices, and other advanced services.

Ember claims its T1430 system, developed with Texas Instruments, is the lowest power ZigBee system. It is due to ship next month and already being used for applications including a wearable health monitor for the elderly, in development at AFrame Digital in Virginia, US.

"This new chip combination will significantly increase the battery lifespan of our product in its small form factor," said Linda Bonanno, chief technology officer at AFrame. The system uses Embers EM2420 radio and TI's MSP430F1612--a microcontroller whose name is clearly designed to compensate for its small size and low--1.1µA standby, 300µA active--power requirements.

Integration Associates and Oki Electric have built a single chip ZigBee device that puts a ZigBee protocol stack from CompXs, which Integration bought last year, on a MAC/PHY chip from Oki. The chip has been certified and will be available in volume in December.

Meanwhile, Chipcon claims the first single chip ZigBee solution, with the CC2430, a second-generation device which includes radio, networking, 128KB of Flash memory and 8KB of RAM, and brings the price down to less than US$4 per chip.

Despite this flood of products, vendors outside of the Alliance are sceptical. "Networks that operate in the 2.4GHz band, such as that offered by Zigbee, will become congested and slow as this frequency is also used by Wi-Fi and other networks," said a spokesperson for ZenSys, a home automation firm whose Z-Wave mesh network operates in a different band, at 908MHz in the US and 868MHz in Europe.

Other vendors showing ZigBee products include Airbee, Atalum, Atmel, Cambridge Consultants, Freescale, Ten X, UBI Wave and ZMD.

Intel is also working on sensor network technologies, but has not joined the ZigBee Alliance. At the Intel Developer Forum last month, Intel showed off motes--small independent computers that can be linked to sensors and used to build a sensor network.

"Motes are the universal building blocks for sensor networks," said Dr Ralph Kling of Intel. Intel is close to launching its second-generation mote, which will include the ability to increase its processing power to handle large amounts of sensor data.

ZDNet UK's Graeme Wearden contributed to this report.