HomeKit Automation based on (dis)connecting of a device

Discussion in 'HomeKit, HomePod, CarPlay, Home & Auto Technology' started by freeman1899, Dec 13, 2018.

  1. freeman1899 macrumors member

    Apr 7, 2015

    is there a way to trigger an automation based on a device connecting or losing the connection.

    For example If light A gets turned on by using the light switch (physically → connecting it to power) I want light B to set its brightness to 100%
    and if light A gets disconnected from the power grid and is therefore not reachable by HomeKit anymore I want light B to be set at 0% brightness.

    A solution involving homebridge would also be great.
  2. Solver, Dec 13, 2018
    Last edited: Dec 14, 2018

    Solver macrumors 6502a

    Jan 6, 2004
    I also have this question. Been trying to figure out a reliable way for HomeKit to trigger or set some uniquely testable condition when a device is not responding.

    My goal was to show a red light if the garage lights had been left on, and no red light if the garage lights were off. If the garage lights are off, all the power to all the garage lights are off.

    Is it possible that one of the many available “home” apps has an answer?
  3. cynics macrumors G4

    Jan 8, 2012
    I'm not familiar with Homebridge however with HomeKit this is possible through a trigger, group, or automation activated by a scene. Depending on specifically what you are trying to accomplish. It easier to work from a power on state though.

    So for example if you are trying to group light B which might be a smart bulb with light A which might be a chandelier (not smart) then I would replace light A switch with a smart switch/dimmer (Leviton makes hub less if you only want one). From there you can group the smart switch/dimmer of light A to B or you can make a simple on and off automation (when switch for light A is on light B do this, when switch for light A is off light B do that).

    When it comes to Home Automation specifics tend to help because other people could have done what you are trying to accomplish but they would need to know exactly what you are trying to do.
  4. freeman1899 thread starter macrumors member

    Apr 7, 2015
    Thank you for your answer. A smart switch would definitely be a valid option for my problem. But maybe there is a solution without buying new gadgets? To explain it even better I will try to be more specific.

    Light A and B are both Philips Hue Lights.
    Light B is always connected to the power grid.
    Light A is turned on and off using a traditional light switch.

    Now I want Light B to turn on and off when I hit that light switch from A.
  5. yass31 macrumors member

    Dec 18, 2017
    It is possible within the Home app.
    -> Automation
    -> An accessory is controlled
    -> Select light A, turn on, next
    -> Select light B, choose the brightness and color you want
    That should do it

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4 December 13, 2018