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TIDM-1021: Water Proof touch design using Captivate solution

Genius 5840 points
Part Number: TIDM-1021
Other Parts Discussed in Thread: CAPTIVATE-PHONE

Hello.

I would like to know following design detail.

My customer are going to make Water Proof touch sensor in horizontal position,so there is possibility that a large drop of water that covers multiple buttons is on the touch sensor for long time.

Under above condition,

 1.Is TIDM-1021 possible to avoid false detection by such a large drop of water ?

 2.Is TIDM-1021 possible to detect touch functionally when there is such a large drop of water?

 3.For running demo to customer, are there any way to get TIDM-1021 demo board?

Regards,

U-SK

  • Hi U-SK,

    Thanks for your posting, we will look into this and get back to you ASAP.

    Regards,
    Ling
  • Hello U-SK,

    1.Is TIDM-1021 possible to avoid false detection by such a large drop of water ?
    We can add the guard channel around the sensors so when the liquid covers both guard channel and sensor we can disable the detection so there won't be any false detection. You can see our CAPTIVATE-PHONE board design which implemented the guard channel and it is capable of block false detection with large drop of water.
    Download the design files: software-dl.ti.com/.../index_FDS.html
    Video of the board: training.ti.com/moisture-rejection-capacitive-touch-designs-msp-mcus-featuring-captivate-technology

    2.Is TIDM-1021 possible to detect touch functionally when there is such a large drop of water?
    This depends on how many sensor electrodes in the design. If only few sensor electrodes and they are far a part from each other then it might be possible. It is much more difficult to handle the liquid when the sensor panel is horizontally placed since the liquid will stay on top of the sensor.

    3.For running demo to customer, are there any way to get TIDM-1021 demo board?
    We currently do not have the demo board available but here is a video for your reference.
    Video: training.ti.com/liquid-tolerant-capacitive-touch

    Please let us know if you have any questions.

    Thanks,
    Yiding
  • Hi Yiding,

    Thank you for your reply.

    Yiding Luo said:

    1.Is TIDM-1021 possible to avoid false detection by such a large drop of water ?
    We can add the guard channel around the sensors so when the liquid covers both guard channel and sensor we can disable the detection so there won't be any false detection. You can see our CAPTIVATE-PHONE board design which implemented the guard channel and it is capable of block false detection with large drop of water.
    Download the design files: software-dl.ti.com/.../index_FDS.html
    Video of the board: training.ti.com/moisture-rejection-capacitive-touch-designs-msp-mcus-featuring-captivate-technology

    TIDM-1021 seems to be protected from fault detection by a lot of water.

    Does  TIDM-1021 include guard channel?

    If no, could you tell me mechanism for protecting from false detection in TIDM-1021?

    Yiding Luo said:

    2.Is TIDM-1021 possible to detect touch functionally when there is such a large drop of water?
    This depends on how many sensor electrodes in the design. If only few sensor electrodes and they are far a part from each other then it might be possible. It is much more difficult to handle the liquid when the sensor panel is horizontally placed since the liquid will stay on top of the sensor.

    I understand TIDM-1021 can detect finger touch when exposed to a continuous stream of water.

    Is my following understanding correct ?

     ・Case 1: When large water drop is staying on touch sensor, CapTIvate can not detect finger touch.

     ・Case 2: When a continuous stream of water is exposing on touch senor, CapTIvate can detect finger touch.

    If yes, could you tell me reason why Captivate can not detect finger touch when case1 only?

    Regards,

    U-SK

  • Hi Yiding,

    Do you have any updates?

    Regards,
    U-SK
  • Hello U-SK,

    1. TIDM-1021 does not have a guard channel and the reason it does not have false detection is because we used the mutual mode design with the driven shield. You can use driven shield to prevent false detection too but guard channel will also be able to prevent false detection from hand wipe down the water from the sensor panel.

    ・Case 1: When large water drop is staying on touch sensor, CapTIvate can not detect finger touch.
    This depends on how big of the water drop and how many sensors electrodes the design has as well as how close between the sensors. If there is big separation between the sensors we can use driven shield to prevent false detection and use dominant element detection algorithm to detect the finger touch.

    ・Case 2: When a continuous stream of water is exposing on touch senor, CapTIvate can detect finger touch.
    It is easier to prevent false detection and also accurately detect the finger touch if the sensor panel is vertically mounted so the water is not statically staying on top of the sensor.

    For more information about the driven shield and how water is affection the self-mode and mutual-mode design please see section 2.2.3 and section 2.4.1 of the TIDM-1021 user's guide.

    Thanks,
    Yiding