3 Replies Latest reply on Jun 27, 2018 12:39 AM by gani

    PCB CapSense Proximity sensors works only touching them but we need to find hands up to 5/6cm

    user_505828688

      Good morning,

      this case is connected with case number 00410446.

       

      You had advised me to redesign the PCB of the card, as the pressure sensors did not work, but unfortunately, marking your directions, we got a bad result.

      I send you, like the other time, the Gerber and the PSoC Creator project we are working with.

       

      Could you tell me how we can solve the problem?

       

      We have to use proximity sensors.

       

      In the previous case, we were talking with Ganesh.

      Thank you

      Alessio

        • 1. Re: PCB CapSense Proximity sensors works only touching them but we need to find hands up to 5/6cm
          nsha

          Hi,

           

          Please elaborate more on your application. I assume you would like to detect hand gestures.

          In that case, you can refer to http://www.cypress.com/documentation/development-kitsboards/cy8ckit-024-capsense-proximity-shield

          The proximity shield could detect hand gestures.

           

          If you would like to detect proximity of the hand at a distance of more than 5 cm, then you could use a proximity loop (Refer to PROX loop of shield kit).

           

          In case you are already aware of the proximity shield kit and would like to detect hand gestures at a distance more than 5 cm, you would have to increase the length of the 4 proximity sensors further. You could try creating proximity sensor using copper plate to check feasibility.

          Else, you could also try simulations.

           

          Thanks and regards,
          Shanmathi 

          • 2. Re: PCB CapSense Proximity sensors works only touching them but we need to find hands up to 5/6cm
            user_505828688

            Goodmorning,

            I followed his colleague's instructions. I modified the Gerber, as indicated, but unfortunately, I can not use the presence sensors and therefore the gesture cannot be implemented.

            I send you the Gerber file and the workspace of the project. Can you help me? I spent a lot of money to follow the instructions of your colleague with no result.

            Thank you.

            alessio

            • 3. Re: PCB CapSense Proximity sensors works only touching them but we need to find hands up to 5/6cm
              gani

              Hello Alessio,

               

              We are sorry for not being clear in the initial review process. The range of bar type proximity sensors will be less when compared to the loop type proximity sensors. The maximum proximity sensing distance assured when using a loop type sensors is equal to the diagonal length of the proximity loop. Basically the bar type proximity sensor has less range when compared to loop type proximity sensors because the amount of capacitance coupled to the sensors will be less in case of bar type when you place hand over the sensor.

               

              The following steps mentioned will increase the sensing range of proximity sensors. Please check the following points once.

               

              Please try increasing the sense clock frequency and decrease the IDAC values for proximity sensors. This will increase the sensor signal. After that try reducing the finger threshold and check whether there is any increase in the sensitivity of the proximity sensors.

               

              While increasing the sense clock please ensure that the sensors are charging and discharging properly. Increase the sense clock frequency up to that extent where all the sensors are charged and discharged properly.

               

              Please go through Manual Tuning practices in page number 17 of the document obtained from the link below. The steps mentioned there will be very helpful even if you move to the new design.

               

              http://www.cypress.com/file/151411/download

               

              In the Layout connect the hatch pattern to shield instead of ground. Connecting hatch pattern to shield reduces the parasitic capacitance of the sensors and thus the sensitivity will be increased and you would have more range.

               

              If the above mentioned points will not work (if you are not able to see any improvement in sensing distance after implementing them) please try to implement the proximity sensors as shown in the image attached. This will definitely increase the sensing distance. To test this we recommend you to use the copper tape and cut it in the form of sensor loops as shown in the image. Use any of our development kit to test the performance of the sensors.

               

              Thanks and regards

              Ganesh