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FDC2214-Q1: How can we decide sensing length?

Yoshiki Ochi
Genius 9435 points
Part Number: FDC2214-Q1
Other Parts Discussed in Thread: FDC2214PROXSEN-EVM, FDC2214

Hi team,

I would like to use proximity sensor to detect human hand and measurement range is 4cm ~ 9cm.
How  can we decide sensing length? Is it related to how large sensor plate is?

Also, could you tell me the difference and benefits between capacitive sensing method and inductive sensing method?

Regards,
Ochi

  • 0
    TI__Genius 17440 points

    Hello Ochi,

    Yes, the sensing range is based on the area of the sensor plate. This application note gives guidelines about the sensing distance for various sensor plate sizes.

    If the target is metal, we almost always recommend using inductive sensing. This is because inductive sensing is immune to the effects of non-conductive targets, so there are fewer possible environmental disturbances. We recommend capacitive sensing if the target is unsuitable for inductive sensing (like a human hand). Both the FDC2x1y devices and the LDC devices use the resonant sensing approach that makes them immune to broadband noise. 

    Best Regards,

  • 0 in reply to Kristin Jones93
    TI__Genius 9435 points

    Hi Jones,

    Thank you for your explanation. I understood I can use FDC devise for capasitive sensing.

    I wonder if is it possible to detect lower than 10cm with FDC device. Figure.3 in application note looks that the detection range is above 15cm.
    Could you tell me whether it is possible or not? If possible, how can we achieve that>

    Regards,
    Ochi

  • 0 in reply to Yoshiki Ochi
    TI__Genius 17440 points

    Hi Ochi,

    Yes, it is definitely possible to detect less than 10cm. The graph shows the maximum detection range for each sensor size; the sensors would also be able to detect targets closer than the maximum, including targets that directly touch the sensor.

    If your customer is interested in experimenting with the FDC2214 for proximity applications I suggest the FDC2214PROXSEN-EVM.

    Best Regards,

  • 0 in reply to Kristin Jones93
    TI__Genius 9435 points

    Hi Jones, 

    Thank you very much. I understood the figure shows maximum detection range, so we can use less than 10cm.

    Regards,
    Ochi