Touch signal value is gradually decreasing with the time even though button is touched

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TaH_4345166
Level 2
Level 2
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Hello,

I am using CY8CKIT-042 PSoC® 4 Pioneer Kit. I am using it for the CapSense design with 10 buttons and 2 sliders.

We are facing an issue where Touch Signal Value in the Tuner graph gradually decreases with the time even though the button is touched. Due to this, even thought my finger is on the button, after 6 seconds it's showing as finger is not active. Facing lot of issues due to this.

Attached the screen recording. Please check on Button1_sns0 value in the graph in orange color.

It's an very serious issue. Seems that sensor is gradually loosing it's sensing over the time even the finger is touched in a span of 6 seconds or so.

Please help as it's an serious and urgent issue.

Please let me know the solution asap.

Message was edited by: Tajpeer H

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1 Solution
BragadeeshV
Moderator
Moderator
Moderator
First question asked 1000 replies posted 750 replies posted

Hi TaH_4345166​,

Thank you for sharing the video. Can you please share the same video showing the raw counts in the graph view, instead of widget view.

Please share the CapSense configuration of your project to help you further (All the software and hardware parameters).

Please check if sensor auto reset feature is turned on in your project.

Check for the peak to peak noise in your system (Ensure SNR > 5: 1)

Can you please make sure you get at least 100 counts (with SNR > 5:1) when you touch the button and set the threshold as mentioned in CapSense design guide :

pastedImage_1.png

https://www.cypress.com/file/46081/download

It will also be helpful if you can share the schematic and layout of your design, project so that we can review them and let you know our comments.

Regards,

Bragadeesh

Regards,
Bragadeesh

View solution in original post

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3 Replies
BragadeeshV
Moderator
Moderator
Moderator
First question asked 1000 replies posted 750 replies posted

Hi TaH_4345166​,

Thank you for sharing the video. Can you please share the same video showing the raw counts in the graph view, instead of widget view.

Please share the CapSense configuration of your project to help you further (All the software and hardware parameters).

Please check if sensor auto reset feature is turned on in your project.

Check for the peak to peak noise in your system (Ensure SNR > 5: 1)

Can you please make sure you get at least 100 counts (with SNR > 5:1) when you touch the button and set the threshold as mentioned in CapSense design guide :

pastedImage_1.png

https://www.cypress.com/file/46081/download

It will also be helpful if you can share the schematic and layout of your design, project so that we can review them and let you know our comments.

Regards,

Bragadeesh

Regards,
Bragadeesh
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Hi BragadeeshV_41​,

Thanks for the information. It was very useful. In my case sensor auto reset was enabled so it was constantly decreasing it's value.

But I have a small query. I had set below software parameters as per below instruction, but my button requires hard press to detect it.

pastedImage_1.png

For example, I am getting a signal value of 380 for one sensor. So I had set FT-300, NT-150, NNT-15, Hystersis-35 & Debounce as 3.

So, I have to decrease these values for a better sensitivity right?

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Hi TaH_4345166​,

You can reduce the finger threshold to see increased sensitivity.  Reduce the other thresholds correspondingly.

Regards,

Bragadeesh

Regards,
Bragadeesh
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