1 Reply Latest reply on Jul 10, 2018 2:58 AM by nsha

    Capsense Express sensor sharing

    david_3006156

      Hey there all,

       

      So I used a Capsense Express chip to very quickly prototype a 2-button + 10-segment slider for a customer project.

       

      It worked, but the client wants a longer slider. It is already at the maximum length without compromising the linearity of the response (It's for audio level, so that linearity is important) - but the Express chips can't do slider diplexing.

       

      I thought if I added a second express chip and put two sliders together, sharing a common sensor in between to avoid a dead-zone, this might do the trick in a very short space of time, as I haven't had to take the time to learn PSOC creator to create the same functionality on a normal PSOC4 chip.

       

      Question is - is that possible? Can one segment of a slider be connected to two Capsense Express chip pins? Would that even work? Would it create a problem with the sensor reading? Crazy idea but I'm running on the desire to implement this as fast as possible.

       

      Cheers

      ~D

        • 1. Re: Capsense Express sensor sharing
          nsha

          Hi,

           

          What is the length of the slider expected in your application?

          Also, which CapSense express device is being used?

           

          If you use a common sensor in between, there may be a clash between the 2 chips, as they might scan the common segment at different time instants.

          For instance, one chip may connect it to ground, while the other chip may connect it to AMUX (to scan).

           

          So, instead of using a common sensor, you can read the raw counts (difference counts) of middle sensors (dead zone) and the adjacent sensors using host controller and calculate the centroid position.

           

          As you have mentioned, you could also use PSoC device.

           

          Thanks,
          Shanmathi