Dublin City University has an international reputation for its research into environmental sensing devices. So when the German manufacturer Siemens needed an automated sensor device to monitor water supplies, it came to DCU.

"We are known internationally as having done a lot of work with sensors for the environment, particularly in water quality," explained Prof Brian MacCraith, director of DCU's new National Centre for Sensor Research. It had already done a number of projects for the recently privatised British water firms and many of these are supplied with equipment from Siemens Environmental Systems, based in Dorset.

Yorkshire Water approached Siemens with an idea for a new sensor to monitor what is referred to as "colour and turbidity", Prof MacCraith explained. "They saw a need for this device. They have a relationship with Siemens and Siemens came to us. They asked us to do a design and they then funded the development."

Turbidity is a measure of the amount of suspended material in the water, bits of solid matter that don't dissolve. Colour is a term used by the water authorities to describe substances that have dissolved into the water. This material isn't usually visible but if blue light is shined through a water sample, the light will be absorbed to a varying degree based on what chemicals have been dissolved.

"We have developed an optoelectronic device in a very compact unit that can measure these two qualities of water," Prof MacCraith explained. Once the project got under way it proceeded exceptionally quickly, he said. "We did the design work in a year" and then Siemens got a unit into production and had the device on the marketplace within another nine months.

The two key design requirements, he said, related to the use of optoelectronics and the development of a miniaturised device. "This had to fit into a very small piping system," he said. The finished device fits into an existing plug opening on the pipe work used for other sampling and testing systems.

Optoelectronics is a specialised blend of electronics and optical devices, a particular strength at DCU which has 15 years experience in the area. The university's sensor research already included a strong multidisciplinary approach and this was applied to the Siemens project.

This was later carried forward when the centre was established with a £9 million (€11.4 million) investment backed by the Higher Education Authority. The centre already has 75 full-time researchers, including academics, post doctoral researchers and students and this was expected to rise to about 100, Prof MacCraith said.

Optoelectronics, he said, meant "using advances in light generation and its transmission. A lot of these things have come out of the telecommunications industry".

It involves blending specialised light sources such as light emitting diodes and laser diodes and electronic detectors that respond to the incoming light and produce an electric signal. This signal is in turn interpreted by the electronics so that meaningful readings can be got from a sample.

"Part of the innovation of this was coming up with a design that allowed the two measurements to be taken simultaneously without interfering with one another," Prof MacCraith said. "The miniaturisation made this quite a difficult task."

The resultant unit is a device about five centimetres around and 10 centimetres long, he said. It uses two different light sources, but the DCU team managed to have these read by a single detector. It measures how light is scattered if there is measurable turbidity and reads a blue LED which provides information about the water sample's colour.

The device is now in use in Britain and it is actively being marketed under the name ClearCense. "They expect to sell thousands of these. They are piloting them in the UK at the moment but this has worldwide application," he added.

The research team and DCU hold the patents for the device and the manufacturing rights are licensed to Siemens so the originators retain a revenue stream from the device. "This is the best model" for commercialising the research, Prof MacCraith said.

"Siemens have since come back to us. They liked the platform so much they want us to develop sensors for other parameters based on this platform."

Prof MacCraith led the research group and he did the development in conjunction with Dr Hugh Masterson. The project also involved three research students.