This thesis deals with a method to optimise the water, energy, and detergent consumption in a dishwasher and washing machine. A new sensor system, the voltammetric electronic tongue has been the key factor in the research. The electronic tongue is a sensor system that uses metal electrodes to apply a potential into a liquid, and a current response is obtained. Depending on the potential, the metal, and the liquid, different current responses are obtained. As the potential and the metals are known, unique "fingerprints" can be made for different liquids. These current responses are rather difficult to overview. Therefore, multivariate data analysis, especially principal component analysis (PCA), is used as evaluation tools.

The electronic tongue can not (usually) measure a specific parameter in the liquid, but a"quality", which gives a summary of the liquid that can be used in many different contexts. The electronic tongue could also be used in many different ways in a dishwasher or washing machine. The most obvious way is to control the process in order to use the correct amount of water, energy, and detergent. Also, it can be imagined that other ways to use it would be to supervise parts of the process, such as water quality, detergent, and rinses in the machines.

Sensors in household appliances have to be very durable, and the electronic tongue is suitable in harsh environments, as the only parts facing the liquid in the machines are metals and filling materials.

The electronic tongue shows promising results when it comes to many of the ways to implement it in a dishwasher and washing machine.