Does the sensor signal spike when Driven-Shield on CSD is used?

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YoIs_1298666
Level 5
Level 5
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Hello,

I am trying a Driven-Shield with a handmade sensor with CSD.

YoIs_1298666_0-1616997746773.png

0.01uF is implemented in the shield tank.

YoIs_1298666_0-1617169629294.png

If I touch the sensor and release my finger suddenly, a spike will occur in the sensor signal.

What are the possible causes? 

YoIs_1298666_2-1616998100255.png

 

Best regards,

Yocchi

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1 Solution
Hari
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hello Yocchi san, 

 

Can you share the snapshot of the sensor layout that you are currently testing? 
Also, is this device battery operated or powered using mains? If it is powered using wall-power then the reason for this could be finger injected noise. 

 

Also, are there any noisy signals in the design such as a motor or relay?

 

Note that the resolution here is simple and using a median firmware filter will eliminate this spike noise. 

 

Best regards, 
Hari 

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2 Replies
Hari
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hello Yocchi san, 

 

Can you share the snapshot of the sensor layout that you are currently testing? 
Also, is this device battery operated or powered using mains? If it is powered using wall-power then the reason for this could be finger injected noise. 

 

Also, are there any noisy signals in the design such as a motor or relay?

 

Note that the resolution here is simple and using a median firmware filter will eliminate this spike noise. 

 

Best regards, 
Hari 

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Hello Hari-san,

Thank you very much for your help.

I enabled "Enable median filter(3-sample)".

YoIs_1298666_0-1617165918443.png

The spike noise was gone.

YoIs_1298666_1-1617166032945.png

> Can you share the snapshot of the sensor layout that you are currently testing? 

See the snap below.

YoIs_1298666_2-1617166213104.png

> Also, is this device battery operated or powered using mains? If it is powered using wall-power then > the reason for this could be finger injected noise. 

It is a stable power source and not a battery.

> Also, are there any noisy signals in the design such as a motor or relay?

There is none.

Best regards,

Yocchi

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