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PSoC™ 4

FlKr_2647891
New Contributor II

Sometimes the Capsense slider skips some values, so it is not possible to get every step in the resolution even with slow and gentle fingermovement. SNR seems good enough for resolution of 100.
Is this only due to sliderdesign or can I improve this on the softwareside?

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16 Replies
SrikanthD_56
Employee

Hi

Try changing the Finger capacitance parameter in the CapSense component settings and see that helps. Alternatively, you can try using an overlay on the slider. Please check CapSense component datasheet for details.

Cheers!

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FlKr_2647891
New Contributor II

I am quite familiar with capsense...so of course I have tried the simple things first.
Finger capacitance has limited influence on this...

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BragadeeshV
Moderator
Moderator

Hi,

For slider widgets, each individual slider segment should fall in the same CP range as supported for button widgets. In addition, CP of any slider-segment should be greater than 75 percent of the CP of the maximum CP segment in the slider. For example, in a slider, if 30 pF is the CP of the maximum CP segment, the CP of other segments should be greater than 22.5 pF.

Can you please measure the Cp of the sensors and check if this condition is true in your case?

Please refer to section 7.4.3.1 Slider-Segment Shape, Width, and Air Gap in PSoC 4 Capsense design guide for more information on how to get a linear response.

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

Please let us know in case you need further help.

Regards,

Bragadeesh

Regards,
Bragadeesh
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FlKr_2647891
New Contributor II

Is it possible to measure Cp with the controller or do I need to measure with an external LCR Meter?
If yes, where are these values stored?

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BragadeeshV
Moderator
Moderator

Hi Florian.Krechel_2647891​,

You can measure the Cp of the sensors using CapSense Component or using an external LCR meter. Please refer to the following link to know how to measure Cp of the sensor using the capsense component.

Measure Cmod and Cp of PSoC 4 CapSense - KBA225808

Please let us know in case you need further help.

Regards,

Bragadeesh

Regards,
Bragadeesh
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FlKr_2647891
New Contributor II

I want to measure the capacitance of the sliderelements, but i have problems using the api because the creator says that it is a undifined reference.

I tried it like this with the CY8kit-043:

variable=CapSense_GetSensorCapacitance(CapSense_LINEARSLIDER0_WDGT_ID, CapSense_LINEARSLIDER0_SNS0_ID );

Can you please give me advice on this?

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BrandonP_16
Employee

Hi Florian,

If you want to use the function of measuring the sensor capacitance, you should enable the self-test library in the CapSense component.

You can find the check-box in [Advanced]-[General] tap in CapSense component.

Thanks,

Brandon

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FlKr_2647891
New Contributor II

t.JPG

I get these errors if I try to compile it with the self test library enabled in the capsense module.

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BragadeeshV
Moderator
Moderator

Hi Florian.Krechel_2647891​,

Can you please let us know the following to understand your issue?

1. PSoC device (part no)

2. CapSense component version

3. PSoC Creator version

If possible, share us your project file focusing on the issue.

Regards,

Bragadeesh

Regards,
Bragadeesh
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FlKr_2647891
New Contributor II

Like I said in post 7 I am using the CY8kit-043.

I can share my project with you as it is almost empty, I just configured Tuner, UART and a Capsense Slider. I couldnt find a way to attach my project to this Post, could you please give me advise how you want my data?

my PSoC Creator version Information.

Environment:

PSoC Creator  4.2 (4.2.0.641)

Edit: I just tried all different settings and the problem is the Csh initialization with iobuffer. If i enable this like it is recommended in the guide it gives me the errors i described

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BragadeeshV
Moderator
Moderator

Refer this article for details on archiving: Archiving a PSoC Creator Design

Click use advanced editor in the top right corner and attach the archive file.

pastedImage_1.png

Regards,

Bragadeesh

Regards,
Bragadeesh
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BragadeeshV
Moderator
Moderator

Hi Florian.Krechel_2647891​,

Do you have any unanswered questions in this thread?

Regards,

Bragadeesh

Regards,
Bragadeesh
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FlKr_2647891
New Contributor II

I could manage to measure the sensor capacities. They are 8, 8, 8, 10, 10. The difference is marginal and seems quite fine.

What is meant with

"In addition to these functions, the BIST library also supports shield sensor, shield tank sensor, and CSX integration capacitors. For more details, see the PSoC4 CapSense Component datasheet, or contact Cypress Tech Support."

source: Measure Cmod and Cp of PSoC 4 CapSense - KBA225808

How can I measure these things.

Is it possible to adjust just one paarameter like the noise treshold and still use smart sense?

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FlKr_2647891
New Contributor II

I found another issue. The logging feature from the Tuner is not very good. I simultanously logged the signals with the tuner and sent the sliderposition over serial connection.

slidertunerlog.JPG

Above is the tuner result, plotted with excel. A lot values are missing.

slidertuartoutp.JPG

Above the results from getcentroidposition written to uart and plotted with exel.

Why is this? Can thi be improved. I already configured the i2c for the tunerspeed to 1 Mhz.

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BragadeeshV
Moderator
Moderator

Hi FlKr_2647891​,

Can you please check if the synchronized check box is ON in Tuner?

This may also be because Tuner tends to skip certain packets if the scan happens faster than the speed at which Tuner master reads the data from the PSoC device. This is not an issue.

Also is the original issue "slider skips certain values" resolved?

Regards,

Bragadeesh

Regards,
Bragadeesh
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BrandonP_16
Employee

Hi Florian,

I think you can try simple tuning to check the solve this trouble if sensor Cp variation is stable and you set the tuning mode to Manual tuning.

1. If slider widget is released during dragging. (Ex. 1->2->3->[slider off]->20->21->22->[slider off]->40->...)

  -> Reduce finger threshold.

2. If slider position jump without slider widget release during dragging. (Ex. 1->2->3->20->21->22->40->...)

-> Reduce noise threshold.

Please capture and share the full CapSense Tuner window to be able to check the symptom (dragging from start point to end point). Also, let us know the Widget Threshold Parameters setting value in CapSense component.

Thanks,

Brandon