2 Replies Latest reply on Jan 24, 2013 4:51 PM by user_14586677

    Problem with linear slider

    srihari.s

       I am using linear slider in my project. When I call Get Centroid Position and start sliding my finger over the slider the value at a particular position varies. I have my resolution as 100. When my finger is on button 3 it varies all the way from 24-50. I dont know whats the reason for this.

        • 1. Re: Problem with linear slider
          user_1377889

          The slider-module is not only looking at the position your finger is on, but on its neighbours as well. So it is able to give you more than one value for each slider-segment.

             

           

             

          Bob

          • 2. Re: Problem with linear slider
            user_14586677

            With that kind of variation it would be pointless to have more than 4 elements in the slider.

               

             

               

            Some notes from design manual -

               

             

               

            In most cases the default value of 8-bit is appropriate. However, in designs with high signal levels due to thin overlays
            or large sensor areas 16–bit  resolution should be selected. Because sliders calculate  finger position using relative
            signal levels of adjacent sensors, saturation causes non-smooth operation and 16-bit resolution may be required.

               

             

               

              Widget Resolution: Select 8-bits unless you are using a slider and the signal is saturating due to thin overlay or
            large sensor area, then select 16-bits

               

             

               

            7.4.1   Opamp Output Pins 
            The opamp outputs are directly connected to P0[0], P0[1], P3[6], and P3[7]. If these pins are used for CapSense, the
            opamps become unusable.  These pins have  higher CP  because they are directly connected to  opamp outputs.
            Therefore, these four pins should not be used  for CapSense. If you must use these pins,  they should be used for
            buttons and should not be used  as  sliders or  touch pads. Also, the traces for these pins should be short  to help
            reduce CP.

               

             

               

            Regards, Dana.