3 Replies Latest reply on Sep 25, 2017 10:10 PM by DaC_1685686

    Capacitive Keypad help needed



      First of all thanks to help with previous project on this community page i had a successful product.


      I have a new project with a capacitive keypad that i am trying to use my cypress development board with.

      I have managed to get the software to work with the keypad but i am getting a lot of cross talk between buttons close together.

      I have plugged the outside trace into the ground but i have a feeling i am supposed to be doing something different than plugging into ground.

      can someone please tell me am i supposed to be doing something different with this outside line that goes around all the buttons.


      Thanks in advance.

        • 1. Re: Capacitive Keypad help needed



          Can you please share your project gerber files to review?


          Are you using Self capacitance method or Mutual Capacitance method? Which CapSense component version you are using?


          Are you able to see the SNR of each button in the keypad in the CapSense Tuner GUI? If yes, could you please tell that?


          Try with software tuning of CapSense method i.e. mentioned in the document obtained from the link below if you are using the old version of CapSense component i.e CapSense CSD v2.60 or lower. You can also get information regarding how to measure SNR in the following document using Ca[pSense CSD.




          If you are using latest version of CapSense component please let us know.


          Thanks and Regards


          • 2. Re: Capacitive Keypad help needed



            Please find the attached tuning and data monitoring guides for old and latest versions of CapSense components i.e. CapSense CSD V2.60 and CapSense P4 v3..10 and higher. These guides might be useful for you to tune the CapSense parameters for your application.






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            • 3. Re: Capacitive Keypad help needed

              Hi Ganesh,


              Thanks for your reply, sorry for my late reply i have been on leave.

              I have tried to attach a link to my sample file i have been using.

              I have mostly got it all to work except one of the sensors does not seem to respond very good and it has something to do with scan order as if i change this the problem moves.

              As i previously mentioned i have no idea what to do with the outside trace that goes around the keypad and i have been plugging this into PO4 which is pin for CMOD.

              I have no idea if i should be plugging this outside trace that goes around all buttons and wheel into this pin or the ground pin or if i should be making it into a shield of some sort.

              This is the pin i have been having trouble with and i imagine is hampering my efforts with my lack of understanding.

              Can you please have a look at the file and let me know what i could be doing to improve it.