In this work it is proposed a new tool to measure crop water-content using RF communication signals from nodes of a wireless sensor network. Accurate measurement is obtained combining data from many nodes spread in the crop field. The mathematical model of the measuring process is discussed and experimental data are presented supporting the model.

The measurement of electrolytic conductivity is widely applied as a control parameter and its relevance is continuously increasing, not only in industrial applications but also in the environmental monitoring domain. In this work the attention is focused on the electrical behavior of low cost in-situ four electrode conductivity cells for water quality monitoring in estuaries and oceans. The design of each cell, the choice of the cell constant suitable for the range of conductivities to be measured, the modeling of the current density distribution using a finite element method are described in detail. The experimental characterization of the cell versus frequency, temperature and salt concentration is also carried out. A frequency range where parasitic effects are minimized is identified.

In this paper we describe an inductive sensor constructed as a double transformer, to be utilized to measure the water salinity in the sea and estuaries. The sensor uses two toroidal cores. Each core is provided with one single winding. The windings have equal number of turns. The electromotive forces developed in the water give rise to electrical currents which act as the secondary currents of one transformer and the primary currents of the other. Therefore, the relation between the voltage applied to the primary circuit and the voltage in the secondary depend on the conductivity of the water.

We aim for realizing a robotic system that hands over necessary objects to a user as soon as he/she attempts to reach out for it. In this study, we adopt self-moving trays as robots. In order to hand the objects to the user, the system has to predict the user’s hand movements and adapt to them. In this paper, we propose a method to predict durations and final positions of reaching movements of the user's hand. We apply the minimum jerk model to the prediction and estimate parameters of the model by using Levenberg- Marquardt method. A description of the experimental results demonstrates the usefulness of the method proposed here.

ElectroMechanical Film (EMFi1) is a thin, plastic material that can be utilized as a sensor and actuator. We have tested the material in three different applications. A prototype of a chair equipped with EMFi sensors was constructed in order to monitor pulse, breathing and other activities of a person sitting on the chair. Measured information can be used to study human behavior during computer use. Pulse and breathing were noticed to be easily found from measurement signals of a person sitting restfully on chair. Ultrasonic radar that is based on EMFi has been built and studied. EMFi is quite new material in the field of ultrasonics and has favorable properties like good matching to air in comparison to present transducer materials. The device detects, if there is an object in front of the transducer. Measurements of directivity pattern of the built transducer, transmitter output and receiver sensitivity are presented. Some experiments were carried out to determine device’s ability to detect different objects. A flexible and thin headset prototype including microphone and earphone was realized by using EMFi material. According to the preliminary tests the sensitivity of the microphone is adequate.