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FDC1004

Vignesh TG
Prodigy 155 points
Other Parts Discussed in Thread: FDC1004

Hello

I'm trying to develop liquid level sensing by FDC1004.

Sometimes, the capacitance will be varied even though the condition is not changed. 

May I know why it is happening?

FDC1004 has two different configuration. One is Single-Ended, the other is Differential.

Q1) Generally, which configuration do you recommend for liquid level sensing?

        Our target sensing level is 1cm - 25cm.

Q2) Is the capacitance getting from singe ended is same as differential mode?

Q3) Can I get source or library files for FDC1004 to be used with Arduino 

Q4) When the environmental electrode is used, the capacitance of environmental electrode is getting saturated for empty container itself. May I know the solution please?

Best regards,

  • 0
    TI__Genius 17440 points

    Hi Vignesh,

    1) Either differential or single-ended configurations can be used for liquid level sensing. The key benefit of the differential configuration is its immunity to environmental changes. Even if your application is indoors, this may still be beneficial to you. Most capacitive sensors (except our resonant sensing devices, the FDC2x1x series) are affected by fluorescent lights, which will significantly increase the noise floor when turned on. The differential configuration would reduce this problem.

    2) The capacitance measurements will be different in single-ended and differential mode. See section 8.4 of the datasheet for details.

    3) We do not have any libraries for Arduinos specifically, but we do have sample code available. This can be found at the bottom of the FDC1004 Tools & Software page.

    4) TI would suggest using the CAPDAC to offset the container's capacitance. See sections 8.3.2 and 8.6.2 of the datasheet for CAPDAC details. You could also use a differential configuration between your liquid level sensor and your environmental sensor. 

    Finally, the FDC1004 product page has several application notes specific to liquid level sensing that you may find useful.

    Regards,