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Other objects that are sensitive to the fdc2214?

Berylson Mansingh
Prodigy 10 points
Other Parts Discussed in Thread: FDC2214, LDC1614, LDC1312

Hi ,


 I wanted to know what other materials are sensitive to the sensor with FDC2214 with a copper sensor plate.
  • can it sense wood, steel&other metals, plastic, with same accuracy and resolution  as that of human body?
  • Does the Thickness of the copper sensor plate play a vital role in the detection, if so what is optimum thickness?
Thanks
  • 0
    TI__Genius 9430 points
    Hi Berylson,

    Thank you for the question. That would depend on your application. Are you trying to use the FDC2214 for proximity detection of wood, steel, plastic, etc? In this case, the response would not be as good because the sensitivity would not be as high.

    For sensing anything conductive, like metal, I would look into the LDC1614, which uses a similar LC tank based sensing solution for measuring metals (it varies the L instead of the C). That part has fantastic resolution.

    For any other insulating materials you might be able to use a parallel plate sensing topology, but you would need to see how much of a capacitance change you get for different materials (you are essentially changing the dielectric constant of the capacitor formed by the two plates. Just single-ended sensor like we use in proximity detection for humans wouldn't likely work well. Definitely not to the same accuracy and resolution.

    In regards to thickness, this doesn't play a big role in sensitivity. The big variables are area of your sensor. Most of the sensors we use are printed on a PCB, so it's whatever copper thickness you use for the rest of the board.

    Hope this helps,
    Nate
  • 0 in reply to Nate Enos
    Intellectual 260 points
    The LDC 1614 only has a sample rate of about 4ksps, is there any other device that gives a higher sample rate ?Also does LDC1614 keep 28bit resolution even at 4+ksps??
  • 0 in reply to Tony Philip
    TI__Expert 8050 points
    Hi Tony,

    The resolution would be lower at increased sampling rate. For the exact relationship between effective bits and sampling time, please refer to Section 7.3.2 of the LDC1614 datasheet. LDC1312/4 can go up to 13.3 kSPS, with trade-off in resolution.

    If you have additional questions related to the LDC products, please post them in the LDC forum.

    Regards,
    Yibo