Is an air gap between sensor PCB and covering material allowed?
No air gap is allowed between the sensor PCB and the covering material or case of the product. Less of the electric field extends above plastic when there is an air gap, and the field dissipates in air. These combine to decrease the sensor response. Also, the plastic or other covering material may bend on contact, and the user may interfere with more or less of the electric field than before. This results in a non linear response from the sensor. These two effects combine to give an unpredictable response from sensor, making it unusable. 3M 467MP double-sided tape or similar to – glue or tape the sensor PCB to covering plastic. 2-layer or 4-layer PCB? Choose a 4-layer PCB design when there is no room to route from the AD714x to and from the sensors, outside of the sensor active areas. If there is room on the PCB to route to and from the AD714x, then a 2-layer PCB can be used. What is the maximum distance between sensor traces and AD714x? Maximum distance between sensor trace and AD714x
