• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 2 answers
  • Subscribers 31 subscribers
  • Views 242 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

FDC1004: detect moisture

Marc Friedheim
Prodigy 110 points
Part Number: FDC1004

Hello, I'm trying to measure moisture on a sensor using the FDC1004.

Measuring objects is not a problem but a thin layer of moisture or water is difficult to detect.

How to improve signal from a sensor and chip side?

Is this chip the right solution or is there a better solution?

Thanks!

  • 0
    TI__Mastermind 40295 points

    Marc,

    Thank you for your post and your interest in TI products.
    We do have dedicated humidity sensors in our portfolio.
    You can start looking at them here.

    In the mean-time I will pass this thread to one of the apps engineers in that team, and they will follow up with you on this thread.
    If it turns out the FDC1004 is the right part, they will circle back and I will re-start support on your inquiry.

    Regards,
    John

  • 0 in reply to John Miller - Sensing
    Prodigy 110 points

    Hi John, thanks for your reply. We do want to measure it 'the capacitive way'. This allows us to have some more options. 
    I will wait for the engineer to respond on how to solve this with the FDC1004.
    Thanks, Marc

  • 0 in reply to Marc Friedheim
    TI__Mastermind 40295 points

    Marc,

    The other team's portfolio consists of dedicated humidity sensors, which aren't based on something like the FDC1004.
    They won't have any 'hacks' to offer on using the FDC1004 to detect humidity.

    You can find a comprehensive list of collateral related to the FDC1004 here.
    Please take a look at this to see if it offers anything that is useful for your application.

    But, to be honest, much of our collateral is dedicated to detecting liquid level, when the liquid is non-conducting. 
    We have no experience using the FDC1004 to detect humidity, since that capability is offered by our humidity-sensing portfolio.

    I suspect the first step will be to understand the relationship between humidity on and in the sensor plates, and the subsequent impact on the capacitance at 25kHz, and over any temp extremes for your application. I am sorry to say we don't have any experience to offer there. 

    Regards,
    John

  • 0 in reply to John Miller - Sensing
    TI__Guru* 91206 points

    Marc - 

    As John stated, the HDC2 and HDC3 devices he pointed you to measure relative humidity and temperature. Keeping track of these values will give you the ability to note when condensation level / dew point is met, producing perhaps a usable parameter for you to take action on. Another thought I had was if you are looking for surface moisture that is being directly introduced, you may have a look at the IWR based mmwave devices, they should also give you so ability to "see" the buildup on a surface as the RADAR return will change slightly a layer of water is present on a material, this could also be done with lower frequencies too, I suppose, but I would probably attempt that with a pair of  high Q tuned (in situ) magnetically coupled coils, using one a TX and one as RX, thus creating a strong current magnetic field that might be easily disturbed by the moisture. We make an RFID reader IC family (TRF796x and TRF79xx) that could be used for this - another thought with that same hardware you could see a change in slope within a window as was done here for card detection, this circuit could also "see" other things, too and discern from different materials even, after we baselined it and figured out different "signatures" for the various things that we could introduce in the field.

    https://www.ti.com/lit/an/sloa184/sloa184.pdf