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PSoC™ 4

Level 5
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Level 5


My customer use CapSense.

My customer wants a liquid tolerance layout in one layer.

So I thought about the layout as shown below.


The guard sensor will be cut off in order to realize it with one layer.

Is the function of the guard sensor maintained even in this case?

I would appreciate any other advice on layout.

Best Regards.

1 Solution
Moderator 50 solutions authored 100 replies posted 50 replies posted

This is comments for liquid proof of 1 layer CapSense sensor design.

Liquid Proof:

  • On mechanism, a guide sensor is just a special button sensor. Its function is(implement in firmware by users): when it is triggered, other sensors wont report touch.
  • With fine tuning(and users firmware code):  when the liquid dropped on guide sensor (like circle A B C), the guard sensor will be triggered. In this situation, this will stop touch report even finger touch on those 3 buttons. This is good.
  • If liquid dropped on the sensor traces or sensors(like D E F):  due to Shield hatch layer existed, there is no couple between the liquid and GND. In this case, it wont generate extra capacitance between the liquid drop and GND, so there wont false touch caused by the that liquid drop. This is good.

Other consideration for 1-layer CapSense sensor pattern design:

  If finger touch on Sensor traces (like circle G H), it has risk to cause false touch report. This will increase the difficult of tuning.

liquid tolerance.jpg

Aiko Ohtaka
Infineon Technologies

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