Contribution to the development of a smart sensor using eddy currents for measurement of displacement

A smart sensor is a device whose response takes into account and corrects for environment variables. This study shows that such a device can be produced. The major influential variables studied were temperature and humidity. The sensor was a sensitive coil inserted in an LC oscillator circuit. Oscillator operation was improved to obtain sufficient stability. Data were acquired on a testbench. Although the measurements were distorted by many phenomena (noise, dilation and so on) it was quite possible to design a displacement measurement smart sensor, based on several theoretical models. They predict a frequency response versus distance and temperature. The experimental results were in good agreement with the models.