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March 5, 2014 08:30


Oxford Flood Network - Using the Internet of Things to Detect Flooding

The Oxford Flood Network

Hi I'm Ben Ward, founder ofLove Hz, an Oxford-based startup specialising in the Internet of Things and wireless sensor networks. We are one of a handful of networks in the UK’s TV Whitespace pilot, organised by Ofcom to explore the technology, and are using it to deploy open source sensor networks in remote locations.  I'm looking for more volunteers who can offer their expertise and would like to take part in the further development of the hardware and software for this project.


Oxford is prone to flooding. Although the Environment Agency give blanket warnings they have a limited number of expensive, professional sensors and the data is not yet available under a full open licence. Even with access to this data, the lack of detail wouldn’t really help understand the streams, groundwater rising and complex basin of the Thames & Cherwell to a degree that can identify flooding at a street level. What we need is higher resolution data.


The Smart City Built by Citizens

In the floodplain of Oxford, members from the local community are installing their own water-level monitoring sensors. Inspired by the crowdsourced Japan Radiation Map they are sharing local knowledge about rivers, streams and groundwater to build a better, hyper-local picture of the situation on the ground.

A variety of locations and methods can be used to monitor water levels. Some properties have boreholes which can be used to determine current groundwater levels. Some have water sloshing about under their living room in their floor void. And those who live by swollen streams have intimate knowledge of the conditions that lead to floods. These are all great indicators of imminent flooding but are often passed by word of mouth in a local community.

The Internet of Things 

Instead of word-of-mouth in a local community low-cost sensors can feed the data to the Internet. Citizens who have local knowledge of the areas likely to flood can install monitors in their own area and contribute to a community map. Crowdsourced environmental sensor data can be collected inform communities of conditions - even down to which streets are currently flooded.

This project aims to produce a working example and reference design showing how to monitor water levels in your own community, forming the basis of a blueprint for communities to build their own sensor networks to highlight their own issues – air quality, radiation, noise, whatever they can find a sensor for.

Tweet My Flood

The data will be published with an open licence so it can be turned into an application by anyone. For example, while the basic output is a heatmap of flooding around Oxford, an app could be written to tweet when water levels threaten your particular property, or to warn of heavy rainfall in the catchment area.

TV Whitespace

To enable the Oxford Flood Network a local company Love Hz ( and telecoms operator MLL Telecom are running a pilot of a cutting-edge technology called TV Whitespace (TVWS).
Ofcom, the UK telecoms regulator, is opening the airwaves for this experiment. TVWS is a technology which uses gaps between TV channels for wireless communication and is particularly suited to machine-to-machine (M2M) communication and the Internet of Things whilst also having applications in rural broadband and disaster communications.

How It Works

titleUltrasonic rangefinders periodically ping the surface of the water, calculating the height to the sensor. This data is sent to the gateway where it is uploaded to the Internet. The small, battery powered, wireless devices can be attached to bridges or overhangs at participating locations, or even under floor voids. The data is analysed by a central system which has been told about typical levels and flooding thresholds. Based on these values a map can be produced with warnings of abnormally high levels or sudden changes in depth.


The Design

We connect small, battery-powered sensors to a nearby gateway (with mains power), then backhaul the traffic over TV Whitespace to a base station (or simply via nearby broadband) and onto the Internet and subsequently the backend database.


Radio Hardware

We use a combination of types of radio devices with different power requirements.


Adaptrum’s ACRS2.0 was recently approved for use in the UK’s TV Whitespace by Ofcom (Q1 2014). Because ACRS2.0 operates at 12v and is still a considerable size compared with the sensors it would be impractical to put them at each sensor. Instead we’re using the whitespace network as a backhaul for sensor gateways. 

Ciseco’s SRF radios provide a short-range low-power radio solution which integrates well with microcontrollers and other off-the-shelf hardware. This reduces time to create a prototype and allows us to develop the sensor network with minimal cost.

Sensor Hardware

The sensor devices consist of a Ciseco RFu328 (an SRF radio with integrated ATMega328 microcontroller) and are compatible with the Arduino development environment. They are equipped with an ultrasonic rangefinder which is suspended above the surface of the water and reports the distance.


The sensors need a gateway to get onto the Internet, so they transmit their readings over a low-power radio network to the sensor gateways, usually situated where there’s power (and optionally broadband).

Sensor Gateways

The gateways consist of a Raspberry Pi with a Ciseco “Slice of Radio” on the GPIO header (a USB variant can also be used) and aggregate the sensor devices before uplinking to the Internet via whitespace or broadband. These gateways contain the logic to aggregate the sensors into datastreams for the database.


Whitespace Radios

Where no broadband is available we can use TV Whitespace. TV Whitespace is an exciting new experiment in allocating spectrum. It's been implemented in the USA and Singapore, Nigeria and will soon be legal in many more countries. The UK regulator Ofcom is currently running a pilot, of which Love Hz is a participant. Because it operates in UHF spectrum we have to share that with terrestrial TV. This is done by checking a database to find available spectrum with the GPS coordinates of the radio. We use Adaptrum’s ACRS2.0 radio to transmit and receive data between a base station and the remote sensor sites.

A guide to TV Whitespace can be found at (particularly the FAQ)


The Flood Network side of the project is currently self-funded by Love Hz. The TV Whitespace pilot consists of a donation of Whitespace equipment by Adaptrum and network build effort by MLL Telecom.

The project is seeking further funding to improve sensor technology beyond initial prototypes and also to develop a blueprint to reproduce this in other communities whilst covering infrastructure costs.

Open Source, Open Data

The project is intended to be open-source and create open data. In a time when the Smart City is a buzz-word in technology companies and local authorities, it’s important that the citizens themselves are empowered by the technology. Asymmetric infrastructure projects lead to mistrust. Instead, communities can take control of their destinies and provide their own evidence for their own issues.


I'm looking for volunteers to help me develop this open source project.

Contributions have already been made by members of Oxford Hackspace and makers from further afield. Help is needed with hardware, installation, software, data management, RF, battery life and organisation, among many other things, so don't be shy. 

If you are interested in getting involved, you can contact me via or visit

Love Hz is an Internet of Things consultancy and systems integrator specialising in wireless sensor networks and TV Whitespace.

March 5, 2014 08:30