Our Recent Researches based on Multi-Functional Sensing and Reference-Free Sensing Techniques

Several kinds of experimental results based on two new sensing concepts called multi-functional sensing technique and reference-free sensing technique are presented. These proposed sensing techniques seem to be useful in the aspects of functional integration and economization of sensors. The former proposed technique, multi-functional sensing is the unique one utilizing only one sensor that has two or more sensing functions and then that can recognize two or more input information in the same time, while the conventional use of a sensor has been dominant which is generally functioned for one sensing purpose. As the example of a multi-functional sensor, a soft tactile sensor to discriminate the surface condition, the softness and the property of test materials are introduced. The latter proposed technique, reference-free sensing is also the novel technique with only two kinds of measurement results at the two different measurement conditions for the expected decision or recognition in the circumstances, and that has no needs of providing of reference data in advance. As the examples of the reference-free sensing, an ultrasonic reference-free sensor for recognizing the existence of water in the oil container, and a reference-free electric conductance sensor for the detection of vehicular engine oil deterioration are described with good experimental results.