A rubber mat with high-conductivity rubber electrodes had to be examined for use as capacitive position sensor.
Therefore, different methods for capacitive sensing were discussed. A measuring circuit for a selected method was developed and a program for the used micro-controller was written to control the capacitance-to-digital converter AD7747 on the board. The measuring circuit can be controlled from a computer via Matlab. For that, a Graphical User Interface (GUI) was programmed.
The capacity values were measured for different positions of an object and a mathematical correlation between the position and the capacity was evaluated. A function was determined to calculate the position from the capacity measurements.
Keywords: position measurement, capacitive, electrodes, rubber
August 12th, 2015