A WIRELESS network designed to let people remotely control every electrical appliance in their home could finally make the dream of the smart home a reality. Called ZigBee, the radio technology is being readied for a 2005 launch by a clutch of electronics companies.
To build a ZigBee network, low-power, two-way radio microchips will have to be installed in many electrical devices or appliances, so that they can be controlled or monitored remotely.
What will it do? Imagine, while at work, being able to check if you have left your garage door open. Or if you鈥檝e left a light on. Or set the heating too high. Did you leave the oven on? Is the alarm set? Such questions could be answered at a stroke simply by using your cellphone to call into a ZigBee base station at home. This controller would communicate with every ZigBee-enabled device and either send you back data on its status or let you change some aspect of its operation.
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Or, when at home, you can use a PDA instead of your cellphone to communicate with the ZigBee base station and control devices as varied as the garden sprinkler, the washing machine or the TV set.
But hold on. Wasn鈥檛 Bluetooth, the short-range radio system built into cellphones and laptops, meant to do all this for us when it was launched four years ago? Yes, but that was before anyone realised how power-hungry it is. Bluetooth is a pretty compulsive communicator: it is always 鈥渓istening鈥� out for transmissions and draining the power of the devices it communicates with. That鈥檚 OK for cellphones and laptops that are recharged regularly, but no good for smoke detectors, say, which run on batteries designed to last months or years rather than days.
So some 70 companies, including Motorola, Honeywell, Samsung, Mitsubishi Electric and NEC, under the aegis of the ZigBee Alliance, are developing smart home microchips that use a host of clever power-saving tricks. Instead of being always on, or at least frequently on, the chips in a ZigBee network are programmed to synchronise their transmissions so that they are all either switched on or in sleep mode at the same time. They only communicate in short bursts and spend most of their time asleep using very little power, says ZigBee Alliance chief, Bob Heile.
By cunningly managing power, the transceiver chips in ZigBee devices go for three to five years between battery changes. With Bluetooth, a transceiver battery would be lucky to last a week.
Heile says the first ZigBee products, due out in 2005, will make the slew of infrared remote controls that litter lounges today redundant. A ZigBee PDA will let you control not just the TV, DVD player and hi-fi, but also appliances like the washing machine, kettle and lighting 鈥� from anywhere in the house.
But another aspect of ZigBee is likely to make it attractive, too. It can form 鈥渕esh鈥� networks in which each device can act like a node, passing data between any number of other devices until it gets to the device that needs it. This is likely to be particularly useful in industry, says Heile. In the event of a fire, say, smoke detectors in a warehouse too far away from the ZigBee base station to raise the alarm directly, would relay the signal via other smoke detectors that are closer. The system has a range of 70 metres. And in the home, meshing could allow wireless ZigBee light switches to double up as sensors for the burglar alarm: crook turns on light, alarm goes off.
Previous attempts to build smart homes have faltered because communications have been slow and insecure. A system marketed by the American retailer Sears in 1978, for instance, used the mains electricity wiring to send signals between appliances. But it never took off because of its slow transmission speed and lack of security: the signals leaked onto the mains supply of neighbours and caused interference. But analysts now think ZigBee has cracked the problem 鈥� by combining its low power approach with high speed and optional encryption to prevent this kind of interference.
Chris Ryan, an analyst with Future Horizons, a UK technology consultancy in Sevenoaks, Kent, predicts that by 2009, the average home will have about 65 ZigBee radio chips chirping within it, perhaps with some of them in advanced toys and robots.
And industry will embrace it, too, believes Richard Traherne of UK firm Cambridge Consultants. 鈥淥ne of ZigBee鈥檚 driving forces is reducing the cost of cabling,鈥� he says: wireless ZigBee devices can be placed anywhere, with no cabling needed at all.
But ZigBee will launch without the fanfare that accompanied Bluetooth鈥檚 arrival in 2000. The ZigBee Alliance is cautious about raising unrealistic expectations about the new technology.
鈥淭he fanfare will come but they want to be sure it will work well first,鈥� says Traherne鈥檚 colleague Tim Whittaker.
