Miniaturised low-cost high precision mass market conductivity and temperature sensor technology

Researchers at the National Oceanography Centre, Southampton, and at the School of Electronics and Computer Science at the University of Southampton have collaborated to produce a low power, small conductivity and temperature (CT) sensor system for high accuracy ocean salinity monitoring. These miniaturised devices use microfabrication techniques similar to those used to manufacture integrated circuits out of semiconductor materials. The conductivity sensor contains several electrodes and a water channel for immersion application. The temperature sensor is based on an electric bridge of platinum resistance thermometers (PRTs). Several high accuracy salinity sensors are commercially available, but they are all large and expensive. Smaller systems have been developed but they are inaccurate. Our current prototype is the size of a 1.5L pot, using 7-electrode and a 2x2 mm water channel for conductivity measurement. A circuit based on trans-impedance amplifiers and FPGA is used to drive the CT sensor and log the data. The sensor system can work for more than one month powered by a PP3 battery. The next generation will use a 4-electrode cell without water channel for conductivity measurement. By integrating all the control circuit into an ASIC, the sensor system can be packaged in a device that will allow use as a high accuracy data logging fish tag. The proposed activity will evaluate if this technology has commercial potential (i.e. can industry make money out of this) and will identify the first steps of a plan to maximise the income generated by this idea. This will include an evaluation of the market for the sensor technology; a review of patents and opportunities for protection of the idea; and evaluating possible partners and initiating contacts with them. CT values not only can be used for salinity calculation, but also are the key parameters for most chemistry sensors. So CT sensing is required by a number of industries (e.g. agriculture, aquaculture, water treatment industries, and offshore industries) and by scientists (e.g. in oceanography, in the study of fresh water systems, and in plant research). We are therefore, hopeful that this idea could have significant market potential and could contribute to the competitiveness of UK industry.