CAP1188 Sensitivity

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  • Hi there! :)
    I recently bought some MDBT42 breakout boards and love them :)

    Now I hooked up a Adafruit CAP1188 touch board to one of them and it works (with the module), but I would need to change the sensitivity of the board and I have no clue how to do that.

    In Arduino this would work:
    uint8_t reg = cap.readRegister( 0x1f ) & 0x0f;
    cap.writeRegister( 0x1f, reg | 0x6F );

    Can anyone point me to the right direction?

  • Fri 2020.04.10

    I have no experience with this specific module. Has the module source been reviewed?­.js

  • Hi Robin,

    thanks for your reply :)
    I managed to get away with the default sensitivity, by rearranging the wiring even though it's all in a very tight space.

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  • Nice, thanks for sharing.

    Do you like to tell us what your project is about?

  • Sure,
    it's a BLE remote:
    Previous, Play/Pause, Next, Volume Up and Volume Down

  • Thanks for sharing, that's what I had in mind when I saw how you place the black circles.

    Any information about the power consumption?

  • According to the datasheet of the CAP1188 chip: "50uA quiescent current in Standby (1 sensor input monitored)". I will investigate more, if i find that the battery drains too fast.
    But at least the cap1188 can send an interrupt, so that Espruino don't have to check the touch values continuously.
    I definitely can recommend the cap1188! At first I implemented the remote with the touch pins of an ESP32, and that did not work very reliably

  • But at least the cap1188 can send an interrupt

    Yes, a setWatch() on an interrupt pin would be much more effective.

    Did you had to create spirals at the cable ends or something similar, to make it more sensitivity?

  • Tue 2020.04.14

    post #7 '50uA quiescent current in Standby'

    As this is a nRf52, Just stumbled across this using Low Level PPI:

    'Hardware capacitive sense on two pins'

    search above string inside:

  • @MaBe: No, the default sensitivity was too high with the way I originally had my wires. So I had to shorten some wires and bend others to have them apart as much as the limited space allows.

    @Robin: oh, nice! might try this one day. Would be curious if I could get that to work more reliable than the ESP32 touch pins I tried initially.
    For now I'm pleased with the setup I have :)

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CAP1188 Sensitivity

Posted by Avatar for SiFu @SiFu