Capsense maximum Proximity sensing

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Anonymous
Not applicable

Hi there,

   

I am using CapSense on a circular board and my aim is to enable wake-on approach from as far away as possible. I have done a first design but I am not totally satisfied yet with the result. Would be great if I could get some additional tips on how to make my design better.

   

Here is what I have done:
- the board is circular, 133mm in diameter (~5.2 inches) and has 4 layers
- I put the circular sensing electrode (1.6mm/63mil width) on the circumference of the top layer (nothing else on the other layers)
- the driven shield electrode is placed right behind it (1mm/40mil width with 1mm/40mil space to the sensing electrode, circular and on top and bottom layer)
- the rest of the circuitboard (all the components plus guard ring) with 1mm/40mil space behind the shield electrode.

   

I studied the available pdfs from Cypress and also the schematic and layout of the MBR3 eval kit. Is there something I could do better layout wise to get a longer proximity sensing distance?

   

Thanks a lot for your help!

   

Regards,
Josef

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3 Replies
rola_264706
Level 8
Level 8
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        What distance are you trying to get? Also you may need to make the board and see how it works. You will need to tune the board to maximize the circuit.   
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Anonymous
Not applicable
        Hi, around 20cm/8inch would be good, 25cm/10" would be perfect 🙂 I will send a new board to fabrication tomorrow, with the previous one i could get 10-15cm/4-6". Should there be a difference if i leave the circular proximity antenna open on one place compared to having a complete circle? Thanks a lot! Josef   
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Anonymous
Not applicable

Hello,

   

Could you please create the tech support case in cypress.com website and share the layout and schematic file, and project so it will help us to analyze the schematic and layout completely. To create tech support case, please go to cypress.com-> Design support-> create a support case. 

   

Thanks

   

Ramesh B

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