Enhanced water and condensation safe touch sensing operation
This application note explains the unique auto-calibration feature of the touch sensor
family from NXP and provides guidelines for enhanced water and condensation safe
operation, focusing on applications with capacitive touch buttons.
Capacitive touch sensing is considered as a revolutionary development to replace
mechanical buttons in all application areas. While providing an easy to implement
hermetic touch interface with no mechanical parts, factors as accumulated
contaminations, condensation and water droplets have been less pleasant topics to deal
with. Robustness is a major concern. Especially in harsh environments as workshops
where contaminations are usual, in automotive applications where extreme climate
conditions apply and also in white goods where wet hands and water splash is
encountered, special attention needs to be given.
Electric filed strength between the sensor pad and the surrounding GND ring
