What is the range of temperature you are varying? Is it in between the acceptable limits i.e -40 to +85 degrees centigrade?
In the firmware change the Tuning method to "Smart sense-Hardware parameters only" and increase the value of Positive as well as Negative noise threshold and check once whether the board is working properly.
Please observe the rawcounts of the sensors using CapSense tuner GUI and see their profile with different temperatures and also when temperature changes gradually. Please attach the screenshots here.
I don't see an option for "Smart Sense-Hardware parameters only". My only options are (Auto)SmartSense, Manual, and Manual with Run Time Tuning.
Internal temperature of our electronics housing should stay under 75c.
You might have using old version of CapSense component i.e. CapSense CSD 2.60 . For all CapSense designs we recommend you to use latest version of CapSense component i.e CapSense V3.10 or higher.
In the old component CapSense CSD v2.60 you can choose Manual with run time tuning and you can change the threshold parameters while running the tuner. Please go through the document in the link below which tells you the procedure for tuning and data monitoring in the old CapSense component.
But it is recommended to use the latest version of CapSense component. Please use the latest version of PSoC Creatoe i.e.e PSoC Creator 4.1 in order to use the latest versions of components .