0 Replies Latest reply on Apr 29, 2019 4:16 PM by MichiyukiY_91

    CapSense Capacitive-Sensing: Liquid Tolerance

      Capactive-sensing is used in a variety of applications such as home appliances, automotive, and industrial applications. These applications require robust capacitive-sensing even in the presence of mist, moisture, water, ice, and humidity changes. In a capacitive-sensing design, false touches or proximity detection  can happen due to the presence of a film of liquid or liquid droplets on the sensor surface, due to the conductive nature of some liquids.  Cypress' CapSense capacitive-sensing provides liquid tolerant features for capacitive sensors. When a liquid is on the sensor, CapSense can identify the capacitive characteristics of a liquid vs. finger and reject false events in wet conditions, delivering a robust, intelligent, and easy-to-use method to get a capacitive-sensing design to production.


      Liquid-Tolerant CapSense-Based Touch UI in a Washing Machine



      To compensate for changes in the capacitive signal due to mist, moisture, and humidity changes, CapSense continuously adjusts the baseline signal of the sensor to prevent false events. To compensate for the changes in the signal due to wet conditions, a Shield Electrode and Guard Sensor should be implemented to provide robust touch sensing.

      Shield Electrode (SH) and Guard Sensor (GUARD) Connected to CapSense Controller

      guard and shield.png


      To find out more, please check the PSoC 4 and PSoC 6 MCU CapSense Design Guide.