Forget batteries, Cambridge start-up 8Power is harvesting energy from vibrations
As the Internet of Things takes off, 8Power is driving the sensor revolution.
One of the world’s most impressive bridges, the Queensferry Crossing, has opened in Scotland.
Spanning 1.7 miles, the £1.35billion cable-stayed structure is now the main route between Edinburgh and Fife, taking the strain from the Forth Road Bridge, built in 1964, which will in future be dedicated to buses, taxis, bikes and pedestrians.
In December 2015, the deteriorating state of the Forth Road Bridge was laid bare when it had to be closed for nearly three weeks due to defective steelwork.
Earlier that year, Cambridge company 8power successfully field-tested some technology on the bridge that could in future prevent such disruption.
The start-up, based at the Future Business Centre in King’s Hedges Road, is developing vibration energy harvesters to power sensors – including the kind that can provide data on structural health.
As the much-heralded Internet of Things finally begins to take off, creating a world of connected devices, the ability to power sensors through natural movements rather than batteries or the National Grid is hugely appealing.
Paul Egan, VP, business development at 8power, tells the Cambridge Independent: “The company was formed to address what we think is the missing piece of the puzzle for the Internet of Things.
“We’re going to get data from lots of sensor networks – some will be wireless, some will be wired. We’ve seen the cost of sensors getting lower, data becoming richer and, with the new generation of wireless networks we’re getting, such as LoRaWAN and narrowband IoT, we’re finally able to address the cost and coverage problems of getting data from devices, which is fantastic.
“The bit that we think is the missing piece of the puzzle is: how are we going to power these things in the field for long periods of time?
“You can have low-power, low-cost sensors to get your data, but if you have a cost associated with powering them – which might be wiring them into a power supply, recharging them or sending someone to change the batteries – that can actually destroy some of the business cases. Our premise is about providing energy-independent sensor systems for a number of applications.”
With its vibration energy harvesting technology in development, 8power also has two other solutions.
“We use the latest generation of lithium batteries, which have fantastic performance and really can last 10 years in the field, but they are still a battery, so we have to be careful about how many times we sense things and how much data we can send back,” says Paul.
“We’re also developing some with small solar panels in them for outdoor applications like tracking construction equipment or rail freight.”
The technology for the premium vibration energy harvesting product was created at the Cambridge Centre for Smart Infrastructure and Construction, part of the University of Cambridge, by Dr Yu Jia, Dr Ashwin Seshia and the Sensors and Data Collection team, and employs a phenomenon known as parametric resonance.
Paul explains: “Vibration energy harvesting has been around for a long time. It’s a simple mechanical process, where if you move a magnet past a coil you can produce power.
“Traditionally you’ll have a pivot and an arm and it’s very much like a kids’ swing. What the guys at the university worked out is that if you can move the pivot point in two dimensions simultaneously – so as well as moving side to side, you move up and down at the same time – you can generate a lot more power. With that configuration, you can move a lot more mass for the vibration that’s going in.
“The physics behind it are unbelievably complicated. But if you imagine a child on a swing moving their legs back and forward to generate power, that’s an example of parametric resonance.
“The upshot is that we think we can produce between five and 10 times the amount of power of existing vibration energy harvesters. That big increase means we can get to the power levels needed to run sensor systems for long periods and generate enough power to run mobile-type communications.
“We’re running through the engineering of how to make this robust enough and reliable enough that we can have things in the field for 10 years.”
The patented energy harvesting device was trialled at the Forth Road Bridge by its creators in April 2015.
“Not all bridges vibrate in the way the Forth Road Bridge does, but they were able to attach the vibration energy harvester to various places and generate enough power to run a small temperature sensor and a wireless remote,” says Paul.
“It’s a steel bridge that is suspended, but a lot of the beams are bolted into each other so the vibration from the traffic actually gets transmitted into the structure.
“It was a proof of concept that there is enough power available in these type of structures that you could put instruments on it. We would term that structural health monitoring.”
About 1,000 sensors would be required on the bridge to collect vibration signatures. Variations in them could have helped highlight the steelwork issue in 2015 before a closure was required to fix it.
“One of the things bridge operators are interested in is excursions from normal operation,” says Paul. “Certainly, had we had vibration sensors scattered across the bridge, we would have been able to detect the strange vibration and known it was roughly in that area.
“So even before the structural failure, we would have been able to pick that up and you could change your maintenance programme.”
He adds: “Having structural monitoring on bridges, tunnels, railways is definitely one of the applications we are looking at.
“What we’re hearing is people want to get a lot more life out of their assets. At the moment, a lot of the maintenance tends to be preventative where you send people every six weeks to do some work.
“People want to move to a more predictive maintenance environment where because you have so much data you can assume the asset is working until you start to get data to the contrary.
“It’s the concept of a digital twin. Bridges and railways, in particular, have a lot of data and you can see in real time what’s happening to these assets.”
On the railways, 8power is working with customers to see if its vibration energy harvesters could be used to track rail freight cars, offering precision reports using GPS to report locations hourly.
“There is a similar opportunity in tracking box trailers used by the supermarket fleet and skid trailers that containers fit onto the back of,” says Paul. “When a trailer is attached to a truck you know where it is, but the moment you detach the trailer you lose visibility on that asset.”
The company is also looking at the oil and gas industry.
“If we can attach to an electric motor or pump or something it would make them incredibly safe because removing wiring removes the risk of any kind of spark,” says Paul.
The company aims to provide an end-to-end solution, with a common hardware platform for each of its systems – battery, solar and vibration-based.
“We’re building a custom circuit board that has all the electronics and power control for each of the power supplies. We’ll be getting a production version with us by the middle of September and that will carry us through the first set of products.
“At the same time we’re working on the data platform that goes with the devices. Getting data is one thing but we need to be able to make sense of it for our customers as well, so we’re putting a lot of effort into designing dashboards to look at the sensor data – it could be location, vibration, temperature. We have a whole sensor pack built into the electronics so we can get a rich data feed.”
8power hopes to carry out field trials by the end of January 2018 – and, when it does, the sensor revolution will truly have begun.
A team with pedigree
8Power only employs a small team at the moment – but it’s a formidable one.
Paul Egan was co-founder of Neul, the Cambridge Science Park-based Internet of Things pioneer that was acquired by Huawei in 2014. Before that, he worked at CSR for a decade on Bluetooth, wireless and GPS. Paul was also involved in the early days of Cambridge chip giant Arm.
Chief executive officer Antony Rix spent nearly 12 years at TTP in Melbourn working on a range of wireless and software products, while chairman Richard Green was co-founder of Ubisense, the global leader in enterprise location technology.
Also working with them is Martin Jackson, who was chief technology officer at semiconductor firm Virata and group head of technology for electrical engineering firm Elektron Technology.
The advisory board includes the academic co-founders, Dr Yu Jia and Prof Ashwin Seshia.
The technology may be low-power, but the company’s board is anything but.
More by this authorPaul Brackley