CapSense capacitive-sensing also provides capacitive proximity detection. Proximity sensors detect the presence of a conductive object (such as a hand) in a three-dimensional space around the sensor. However, the actual output of the proximity sensor is an ON/OFF event, similar to a button. Proximity sensing can detect an object at a distance of several centimeters to tens of centimeters depending on the sensor design. This is also a good replacement for IR sensors and other proximity sensors out in the world today.
Proximity sensing requires electric fields that are projected to much larger distances than buttons and sliders. This requires a large sensor area. However, a large sensor area also results in large parasitic capacitances, Cp, and detection becomes more difficult. This requires a sensor with high electric field strength at large distances while also having a small area. Recommendations are to use a trace with a thickness of 2-3mm surrounding the other sensors.
Proximity Sensor
To find out more, please check the PSoC 4 and PSoC 6 MCU CapSense Design Guide.