3 Replies Latest reply on Dec 27, 2018 10:31 PM by MeenakshiR_71

    PSoC 6 and Mutual capacitance CSX Sensing

      Hi everyone,

      I am looking for informations about CSX Sensing method with PSoC 6. I understand that CSX Sensing method works by transmitting a frequency  on the “Tx” pin and then receiving that signal by capacitively coupling that signal into the “Rx” line but I can't find any datasheet, notes that show a diagram or electronic schematic of how it is wired inside the PSoC.

      Another question, I need to create a matrix with as much electrodes as possible, that's why I am interested   in CSX Sensing, I was reading in the PSoC 4 Capsense Datasheet and found:

       

      Does it means with Matrix Buttons using CSX Sensing method I could measure the Z-axis of each intersections with no limitations?

       

      Thank you very much.

        • 1. Re: PSoC 6 and Mutual capacitance CSX Sensing
          RuzheZ_36

          Hi Alexis,

           

          Sorry I prefer to know the meaning of  "Z-axis" mentioned in your question?

           

          Thanks,

          Ryan

          • 2. Re: PSoC 6 and Mutual capacitance CSX Sensing

            Hi rzzh,

            Sorry I understand that my question could be not clear.

             

            I was making the comparaison with the touchpad where  you can get the X and Y position. For my application I need to measure the Z axis corresponding to the depth.

             

             

            What I want to know is that Matrix button gives

            • just a binary result depending if the sensor pass a threshold or not
            • or It gives an analog value depending on the capacitance between Tx en Rx pins. As you see on my masterpiece () if you approach your finger you should change the capacitance between the Tx and Rx

             

            I hope it's clear

             

            Thank you

            • 3. Re: PSoC 6 and Mutual capacitance CSX Sensing
              MeenakshiR_71

              Hello @user_77989180,

               

              To your question, the touchpad's X,Y output is based on the signal on the RX (and your master-piece is pretty accurate about the Tx-Rx working on a high level ). So it is not simply ON/OFF or TOUCH/NO-TOUCH that is translated to X,Y. You should be able to access the signal on each sensor using "uint16 diff = CapSense_dsRam.snsList.touchpad0[0].diff;" statement. where "touchpad0" is the name of the Touchpad widget and "0" is the sensor index.

               

              However, detecting Z-direction using this approach is a bit tricky. For one, the change in signal because of Z-direction is seen only when the finger is very close (almost touching) and will vary a lot depending on the finger size (bigger finger like thumbs can create more signal compared to say little finger ). That being said, it is not impossible to do it with some conditions specified before hand

               

              Let me know if you need any help with this.

               

              Regards,

              Meenakshi Sundaram R