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MSP-CAPT-FR2633: captivate touch keyboard response

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Replies: 3

Views: 905

Part Number: MSP-CAPT-FR2633

hi all,

a customer of mine has developed a touch keyboard w/ our captivate technology...

he is asking whether (and if yes, how) is possible to detect multiple keys pressed at the same time (or if there will be a dominant one)...

thanks a lot in advance

KR

Vincenzo

  • Hello Vincenzo,

    Thank you for your post. If their application requires detection of multiple touches, they'll need to make sure mutual mode is used, not self-capacitance mode, for the electrode matrix (see CapTIvate Technology Guide > Capacitive Sensing Basics > True Matrix Capability section for more details).

    First, I would highly recommend that they read through the entire CapTIvate Technology Guide to better understand how CapTIvate works. When they do, they'll come across the CapTIvate Technology Guide > MSP-CAPTFR2633 Development Kit > Sensor Panel Demonstrations > CAPTIVATE-METAL Demonstration > Basic Button Touch section which talks about detecting multiple keys.

    Regards,

    James

    MSP Customer Applications

    Check out our new Answers to Common Sigma-Delta ADC Questions on MSP MCUs app note!

  • In reply to James Evans:

    Hi James,

    We've produced several keypads (4x4 touch buttons) but would like greater sensitivity to button touch as well as proximity. We tried to make both more sensitive but are facing some challenges:

    1. When trying to change the parameters of buttons and make them more sensitive, we increase the conversion count as suggested, but the buttons stop working! The same thing happens with proximity as well. Next, we experimented with conversion counts, gain and frequency divider. There is LED (also in our demo project) which is on every time proximity is detected. This LED is never on and the buttons are dead.
    2. About proximity, we tried increased the proximity. Now when we touch the glass (and system is in sleep mode), sometimes it wakes up instantly, other times it takes 1-2 seconds, other times in 5 seconds! The most frequent response is fast, but not always. Also it wakes up by itself without any human around in many meters. Finally when it wakes up it takes a lot of time to go in sleep mode again and we see the proximity LED being on for a lot of time before sleep, but no human is around.
    3. Question: The parameters of buttons (BTN00) affect the proximity (PRX00)? And vice versa?


    Again, the keypad is 4x4 (16 buttons), and I sent you the project offline. Thanks a lot in advance.


    KR,


    Vincenzo

  • In reply to Vincenzo Pizzolante:

    Hello Vincenzo,

    Thank you for your post. Jace has informed me that he'll be working directly with you regarding these questions. Thus, I'll go ahead and close the thread.

    Regards,

    James

    MSP Customer Applications

    Check out our new Answers to Common Sigma-Delta ADC Questions on MSP MCUs app note!

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