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FDC2114: Using FDC2114 to discriminate touch vs objects

Mihai Vintila
Intellectual 590 points

Part Number: FDC2114

Hello, I have an application where I need to discriminate finger touch from a touch with objects (for example a metal object or a fruit or a water bottle etc).

Is it possible to use FDC2114 to differentiate between human touch and an object ?

Thanks,

Mihai

  • 0
    TI__Genius 17440 points

    Hi Mihai,

    This is possible, as long as the objects are measured at a fixed distance from the sensor. This can be accomplished by placing an insulative layer over the sensor. Each object has a different dielectric, so they will induce different changes in the sensor capacitance (and therefore sensor frequency), which the FDC2114 will output in digital format. If the objects are held at the same distance each time, the different objects should produce different output codes. If the dielectrics are too similar or the objects are not held at a fixed distance, the device may not be able to tell them apart. Also note that the size of the objects will impact the measurement as well. Even different fingers will affect the sensor capacitance in different ways. It may not be feasible to differentiate every possible object from a finger, but it could be feasible to differentiate between a discrete number of objects with distinctly different dielectrics.

    I would suggest testing the application using the FDC2114EVM, which can be purchased on the TI store.

    Regards,