Wander through the historic streets of the Roman city of Bath in the UK, and you might sense that they are smarter than average. And you would be right.

It is not just that the streets are clean, it is that intelligent waste bins keep them that way.

The array of solar-powered trash cans deployed around the touristic city centre have the ability to call the council refuse department and let it know when they are about to overflow.

It may seem a ridiculous notion, but these smart bins are pathfinders for the future connected world, where machine talks to machine, and where the mobile networks have robotic customers.

By 2020 there will be 50 billion machines connected across the world, thanks to the growth of wireless data, according to the cell phone giant Ericsson.  Indeed, the wired world passed a landmark in 2009, when the number of people connected to the internet was overtaken by the number of devices.

And a report to the US National Intelligence Council highlighted the “internet of things” as one of the disruptive technologies of the near future: “By 2025 internet nodes may reside in everyday things—food packages, furniture, paper documents, and more,” the expert group wrote.

The basic idea is that if all objects are equipped with basic networking abilities, they can be identified and queried by computers, making the world smarter and more convenient. Applications range from the serious to the absurd. Think of a network of tiny sensors deployed around the world that can monitor global temperature and automatically send that information back to a central location. Or sensor-laden buses, trams and trains that broadcast their location to give commuters real-time updates on their location. Or applications that allow you to control the lights in your home remotely. Or smart fridges that alert you when you have run out of milk. Or – of course – bins that can shout when they want to be emptied.

BigBelly Solar, the provider of Bath’s bins, was an early pioneer of M2M, as this kind of machine-to-machine connectivity has also become called, setting up business in 2003. The company’s approach is a microcosm of what the internet of things could offer.

“Going round Boston,” says founder Jim Poss, “I saw all these overflowing garbage cans, and idling garbage trucks, and every time they stopped and started, there was this big plume of black smoke. And I realised there was a problem.”

The problem was a lack of information. The city sanitation department never knew which bins needed emptying making most trips wasteful.

Putting a solar-powered chip into a low-tech bin may seem an over-the-top solution. But Poss underlines that the sanitation system overall is not low tech. With all the organisation that goes on running it, there’s actually a lot information being processed in the background.

The bins themselves still aren’t that smart – just smart enough. By posting back regular SMS messages detailing how full they are, they give the network the data it needs to plan ahead, to see which bins will need attending to and which route might be optimal for waste trucks to empty them. If some bins are in rubbish hotspots while others are underused, it’s easy to see which need to be moved.

The fact that the information is handled by the company in Boston, and made available to clients over the internet, underlines the connectedness of the system. It is truly a prototype of the bigger internet of things to come. And the room for growth. The company has 18,000 deployed around the world. “But we’ve barely scratched the surface,” declares founder Jim Poss. “There are millions upon millions of very wasteful garbage cans out there. Let alone when we broaden that to M2M devices in general – the world is our oyster.”

Car cloud

For the phone utilities, M2M represents a great opportunity. For one thing, the amount of data a device is likely to send is very small – it won’t put a great strain on the network capacity. And much of the communication is not time critical. Like other public services, phone networks experience a rush hour – typically at the end of the working day, when commuters call home to say they’re on their way and then dial up some tasty video stream. But in the middle of the night, the airwaves are almost silent, a wasted resource.

It would be no problem for low-priority messages to be scheduled for off-peak periods, effortlessly increasing revenue, while more urgent data could be squeezed into temporary lulls in mostly busy traffic.

What scares providers is the prospect of large numbers of machines trying to establish contact with a base station at the same moment – instantaneously congesting the system, and interfering with regular callers’ access. When the internet of things grows well into the billions of connections, that’s going to be a common issue. Unsurprisingly, redesigning the connection protocols to accommodate machine communications is a high priority in wireless research.

Of course, there are many other ways machines can connect into the internet – through wi-fi access, Bluetooth and so on. Much of the connectivity takes those paths at the moment. But where cellular wireless scores over these is in autonomy: not only devices with solar power (or other forms of energy harvesting) that can be freed from the electrical grid, but with mobile connectivity, they can be put in relatively remote locations, or can be free to roam.

Cars are a classic case. With vehicles already extensively run by computer, wired for infotainment, guided by connected satnavs, it’s only natural that they should each become another node in the internet of things. It’s only with the mobile infrastructure they can maintain continuous contact as they move from zone to zone down the street.

There was already interest in using wireless communications between cars as a safety measure. A leading car is less likely to get shunted if it can wirelessly message the one behind that it’s slowing sharply before the brake lights come on. Indeed, in 1999 a band of the radio spectrum – called the Dedicated Short Range Communications (DSRC) band - was allocated specifically for this purpose.

Though Professor Mario Gerla of the University of California in Los Angeles, who’s been looking at vehicle networking for the past decade, thinks auto manufacturers may lose their exclusive access because these safety systems have been so slow to come on the market.

“DSRC was developed to have plenty of bandwidth so that it wouldn’t have to fight [radio] congestion and competition with commercial traffic, to give a clean channel for the safety applications. But the rumours are that it will be taken away. So the challenge now will be to develop safety applications using spectrum that is not totally dedicated to you.”

Among the concepts Professor Gerla is working on is the “cognitive car” – one that uses intelligent spectrum sensing on the fly to identify free bandwidth as it speeds down the freeway (it is a concept similar to cognitive radio, described in the second of this five part series). In the past he’s proposed CarTorrent – a vehicular equivalent of the popular BitTorrent software used to share large files on the internet. In cars, it would allow cars to connect in a flexible way.

In a way, cars in Gerla’s dream would be not at the tips of the branches on the internet of things, but would become part of its fabric. Each vehicle would be a potential access point for the internet.

“What I imagine is that all the vehicles will become mobile sensor platforms, with video cameras and everything. They will produce so much information you can’t upload it all on the internet. So they will have data storage on board, processing power … you’d have a kind of mobile cloud.”

It would work because of the simple benefits it would bring. Vehicles would no longer merely receive traffic reports; they would deliver the information about local driving conditions into the cloud (though they’d need to know the difference between a red traffic light and a traffic jam). Through distributed intelligence, vehicles could cooperatively plan their routes to avoid congestion in critical areas – a 2005 study estimated traffic delays cost the US economy $78 billion.

Energy harvest

Of course, there are potential problems. Everytime you let your computer or router be accessed by other users, you are vulnerable to hacking. This was illustrated in a 2010 study that showed that even built-in tyre-pressure sensors (which wirelessly connect to the onboard computer) are a security weak point. The researchers at Rutgers and South Carolina Universities showed hackers could eaves drop and track the wireless tyre transmitters, and substitute false warning messages.

Any internet of things in the future would have major issues of security, authentication and trust if we are to enjoy the benefits of seamless connectivity. Giacomo Morabito of the University of Catania proposes that trust relationships based on the approach used by social networks. For example, devices possessed by the same owner should trust each other more than those owned by different people. Objects made by the same manufacturer are more likely have common inanimate interests.

“When my Apple computer doesn’t connect to the departmental Microsoft-based printer, why should I go and ask the Mac user in the next office how she does it? This is 2013. My computer should find hers, and they should sort it out for themselves,” Morabito explains.

Power is another issue. For billions of devices to be truly autonomous, there can’t be any worry about when their battery runs out. Here, Moore’s ubiquitous law of shrinking electronics s the net’s friend.

In phones and computers it has meant ever increasing processor potential. But in the other direction it has meant low-level processing for ever decreasing cost. And requiring ever decreasing power.

For Professor Ian Akyildiz, Professor of Telecommunications at the Georgia Institute of Technology, this means the inevitable end point is the internet of nanothings. We don’t want to be aware of the devices that help us in our lives, he argues, so the sensors would have to be much smaller than the microsensors and Radio Frequency Identification tags we see around us now. That would mean they could use much less power, surviving on energy harvested from the environment (see the third article in this series).

Their nano-antennas (made of carbon nanotubes or graphene) would be too small to send and receive radio waves, and so the devices would naturally operate in the very high frequency terahertz range – currently used in airport body scanners. The advantage of that would be that the data rates could in principle be far higher than with radio devices.

The nano-sensors would themselves be networked together, but also be connected into wider internet.

Like others, he foresees the internet of things in the far future being connected into our very bodies, using hybrid components that marry the biological with the electronic. “We could create biological transistors for example, using proteins and graphene circuits,” he imagines.

Body sensor networks made this way could report to your doctor via the internet he claims, and receive instructions the same way as part of your treatment. “It sounds like science fiction,” Akyildiz accepts, “but it’s part of an e-health vision for 25 years in the future.”

Of course, with this kind of intimate connectivity, you would really want to know about the trust and security arrangements. Much sooner, Akyildiz foresees the internet of things improving our lives in all kinds of subtle ways - invisibly controlling the lights, heating, air conditioning in our rooms and offices.

Giacomo Morabito would like a front door to his house that realises when he’s left it open by mistake, and shut itself. Jim Poss would like smart lorries that would know what goods are in the neighbourhood destined to go to the same destination, before they set off half-loaded down the highway.

Morabito says in many ways all the technology is in place to let these things happen soon. But, he says, what’s holding the internet of things back is the lack of a common language, a set of standards that means that billions of devices will connect effortlessly. These standards – whilst perhaps lacking the excitement of many of the applications – are critical. It was the creation of international standards that allowed mobile phones become a worldwide phenomenon.

“There are a lot of smart applications using intelligent sensors already, but it’s in our hands what the internet of things will be by 2020,” he says.

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