Knowledge Base Article
Answer: A CapSense sensor can be extended using any conductive object that makes direct electrical contact with the PCB. However, using conductive rubber could be problematic if it can be deformed. The capacitance of a sensor is based on the shape of the sensor. If the conductive rubber is deformed, it could change the sensor capacitance and cause a false finger touch to be reported.
Refer to Getting Started with CapSense for more information on how to use springs as CapSense sensors.