Four or five years ago, ZigBee had a burst of publicity. Why has it gone quiet since then?

ZigBee promised to integrate wireless sensors - light switches, burglar alarms and just about everything else - into mesh networks, using economical low-power, low-speed connections. Using links defined by IEEE 802.15.4, it promised networked devices with a battery life of five or ten years, that could be installed and left to run.

But what's happened? We've yet to see any ZigBee installations, and we keep hearing of competitors, including proprietary technology like Z-Wave's Zensys, new systems that use IP over 802.15.4, and from Ultra-Low Power Bluetooth, formerly known as WiBree.

We asked Bob Heile, chair of the ZigBee Alliance what is going on.

We haven't heard much about ZigBee for the last couple of years. Is it just progressing rather quietly?

We're moving to complete the specification, and building support in the automation space. It's been very exciting over the last year and a half. We've had a lot of adoption in our core areas.

The most exciting thing has been the discovery of ZigBee by the energy industry. They are looking for a ready made standard in-building solution, for electricity meters. They want to do load control, and have an infrastructure which can start to slow growth in electric demand, using real time pricing information, in lieu of building more power plants than they could ever build.

Have there been any deployments?

There are big deployments in Sweden from the electricity side, since Sweden modified its regulations. Two years ago the Swedes only required electricity meters to be read once a year. They decided to increase that to once a month. To meet this, and accomplish other goals, the utilities are moving aggressively to using interactive, two-directional communications.

A lot of cities and towns are moving in the direction of interactive meters. Gothenburg is rolling out ZigBee-enabled meters across the entire city. They will network inside and outside buildings, and tie up every 200 metres in a communication point. This will be complete and up and running, by June 2009.

There are other projects in Ontario, and Texas. There could look be 500,000 to 600,000 ZigBee enabled meters this year, and there are a lot of trials going on. Over the next three years, there are over 70 million meters under RFP, and a good chunk could go to ZigBee technology.

The benefit is that the ZigBee meter can be read from outside the house?

Yes, but more importantly, either with permission or through third parties, these meters will be able to manage the electric load environments. They can control the lights, and thermostat settings - they are designed to reduce power demands. The utility can send pricing information in real time, so if at 2pm demand goes up, you can access that information and act on it individually, or give your provider the ability to manage the load environment.

It's a neat thing - you can tune the environment in millions of households. It's better than blackouts or brownouts. It gives you the ability to manage the load, but without inducing much discomfort, just a modification of hot water temperature, say. Most people wouldn't notice.

From a consumer perspective, when there's a ZigBee meter in the house, they have a real incentive to go out and deploy ZigBee based home control systems. Once you have started to discover the advantages of something like that, it will have a real impact on people going out and buying more. It helps move ZigBee from a luxury decision into a problem-solving decision, and really accelerates take-up.

And there are products? I haven't seen them in the shops yet.

We're seeing a large number of companies moving from certification and testing to delivering products. There are multiple manufactuerers with thermostats and lighting control systems, all interacting with each other. It's got all the right dynamics for solid deployment scenario this year.

I've been hearing quite a lot from competitive technology. Any thoughts on that?

There are some proprietary solutions, Zenzys is pushing its proprietary Z-Wave technology through the user community.

There's also competition from standards-based sources. What about the IETF's 6loPAN standard, that puts IP packets over IEE 802.15.4?

Even though it wears IP in its title, it turns out it's not real IP. You have to use bridges and gateways to connect to the Internet. You can address all ZigBee devices from the Internet already. When people say what does this do and what do I need, I say ZigBee already does that.

I don’t view that as serious competition. ZigBee is aimed at the mainstream market, solving 80 percent of the problems in the market, the broadbased requirements of command and control networks for residential and commercial buildings. It meets those requirements at the security levels they require.

What about ultra-low power (ULP) Bluetooth? That offers low-power network connections potentially from a massive number of handsets.

I don't put them on the radar screen. It's just Bluetooth with frequency hopping turned off. It's enough to allow an ultra-low power front door, a door you can control with your phone, without the batteries going flat.

The phone could have dual-mode capability, but it's a very particular capability. It's not a networking solution, as it allows no more than eight devices. It's narrow band, it's got a very restricted range, it's got no special modulation, no nothing.

It solves one problem for Bluetooth in the sensor space - the battery drain issue. But other problems will prevent it from becoming a viable large scale mesh network. You couldn't use this as a smart metering technology. Bluetooth is great for wireless headsets.

ULP Bluetooth is a non-starter for any of the whole-home applications ZigBee is aimed for. It broadens the applications for handset manufacturers, but it only addresses about one percent of the ZigBee market.

Even if it gets critical mass because of the number of handsets, it still doesn't solve the problem. There could be as many nodes out there as you want, but they can't form a network bigger than eight devices, and you can't download that ability later. It makes your phone a little bit more useful.

Is the ZigBee community solid?

Membership in the ZigBee Alliance, has never grown faster than in the last six months. We have 260 members, and we're expecting to see a steady growth. I'd like to see us cross 300 members this year - and there is a huge number of products on the way.

There are at least 50 products on the Alliance site, and in various states of certification. We have quarterly testing events, and over the last two of those, the number taking part has has jumped into the high twenties and low thirties of companies. Companies go to those events to shake out developments early on, and they usually go to two or three. So when those numbers jump, it's a precursor to very large number of products.

When we spoke before, the measure of success was how cheap the chips were. How is that progressing?

We have many classes of supplier. We've got seven of the top ten semiconductor makers, and several fabless members, There are single system-on-a-chip implementations, with everything from the radio to flash memory and a USB core. It takes $2 to $3, to make completely functioning systems.

There are also two and three chip solutions. You might think these add to the cost - it does if you buy the whole solution, but a lot of products already have a microcontroller and memory, so all they is transceivers, which are less than $1. You could put ZigBee solutions in very inexpensively.

That's exceeded my wildest expectations. I thought it would be another year, or two years, before we got there.

So where will it be used next?

I expect to see forms of ZigBee in DVD players, and so on. One very powerful area, is to manage those devices. ZigBee could be helpful in reducing standby currents, by allowing a very low sleep current. When nobody is near a device, there is no need for it to be in a semi-active mode; it could be in deep sleep mode. It comes to a more active mode when people are near.

A typical home entertainment system, just sitting there, can be consuming 100-150W, that's a lot of energy, while it is sitting there waiting for you to light the screen up. If I can get that down to a few mA, this is a lot of energy saved.

That's another opportunity for load-shedding. You can take advantage of this, and I won't notice when something has changed.

Cost-effective cheap sensor networks are going to be part of our future. It makes me believe that a chunk of those solutions will be ZigBee-based.

Other people have built phone cards with ZigBee inside. In Korea, SK Telecom has a ZigBee-based sim card, up and running. Even sitting inside the phone behind the keyboard, radio waves can squirt out the sides. Even though the range is relatively short, as soon as you hit the first ZigBee network outside the phone, can go kilometres.

Has ZigBee taken off slower than you hoped?

I think we were expecting it to go faster than it could have done. There is a certain market adoption rate. In principle things have to take time. We are dealing with a lot of very conservative industries, that tend to take their time making technology choices.

White goods, and industries like utilities do not move quickly, for good reason. Even though the capability was there, they were taking their time on deployments.

Things are slower than we'd hoped for - but if we'd thought more carefully about the reality of market dynamics, we would have realised it would be like this. But now there are real opportunities to participate in global solutions, and we can start to talk about more aggressive take-ups.