A network of smart sensors, connected together using spare TV spectrum known as white space, could soon be Oxford’s frontline against flooding.
The project, which has been running since October 2014, is now experimenting with how drones could be used to monitor river levels. And the more data the network has, the smarter it will become.
"Its not about having your own sensor it's about sharing your readings with the rest of the community," explains Ben Ward, founder of Flood Network, the startup that developed the sensors.
The shoestring project has been hacked together using cable ties, Raspberry Pis, waterproof casings from DIY stores and an antenna found on eBay. But it is the availability of TV white space that really excites Ward. "Essentially, when you're running a white space device you're operating a TV broadcast, which is fun." White space is the leftover spectrum from when the UK switched from analogue to digital TV, with vast swathes made available for early adopters to experiment with.
Sensors have been placed along a number of small rivers that surround a community garden on the outskirts of Oxford, with ultrasonic range finders used to detect water levels. This data is then broadcast over short distances to a base station -- a TV mast with a Raspberry Pi attached to it -- before being sent over the internet to a central hub where river levels are automatically plotted on a map. The data is open, so anyone can access and share it.
Nominet, the non-profit company that handles the UK's domain name registry, has developed an internet of things back-end to handle the network through a process known as dynamic spectrum allocation. Devices negotiate to use bits of frequency at certain ranges and strength and then push data collected back to the internet.
In the future Ward envisages fleets of autonomous drones flying out to gather the vital data before sending it back over white space, giving an even more detailed picture of water levels without the need to install fixed sensors. "It lets us reach into rural areas where there's no connectivity."
Unlike mobile data networks, which cost millions to implement and are ill-suited for low-cost experimentation, white space has an incredibly low cost of entry. It allows projects to spring up and succeed, or fail, fast.
Simon McCalla, chief technology officer at Nominet says this is the most exciting thing about white space. "You can prototype really quickly, create a trial quickly and very cheaply and see whether its something that's useful to deploy on a much larger scale"
Trials using white space are underway across the UK. On the Isle of Wight, where Guglielmo Marconi first demonstrated long-range two-way wireless radio communication in 1897, an experiment has shown how white space can make it easier for ships to communicate and even broadcast superfast broadband. The technology would replace outdated VHF radio, which has a maximum range of 111km.
A similar trial on the Isle of Bute has also connected remote communities in Scotland, bringing broadband to remote areas unlikely to ever be covered by fibre networks or 4G.
But it isn’t just rural communities that will benefit from the coming white space revolution. The technology could also bring ubiquitous Wi-Fi to cities, filling in the gaps where conventional networks fail.
Earlier this year communications regulator Ofcom gave the green light for further use of TV white space following what it deemed a "successful" trial period. Commercial uses of the technology should start appearing later this year.
This article was originally published by WIRED UK
