# Capabilities starting with measure\_ will automatically try to trigger a Flow , what to define in the app.json?

**URL:** <https://community.homey.app/t/capabilities-starting-with-measure-will-automatically-try-to-trigger-a-flow-what-to-define-in-the-app-json/20512>\
**Category:** Developers\
**Created:** [November 10, 2019, 5:55pm UTC](https://community.homey.app/t/capabilities-starting-with-measure-will-automatically-try-to-trigger-a-flow-what-to-define-in-the-app-json/20512 "2019-11-10T17:55:12Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Edwin\_Biemond](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/edwin_biemond/32/72686_2.png) [@Edwin\_Biemond](https://community.homey.app/u/Edwin_Biemond)\
**Post date:** [November 10, 2019, 5:55pm UTC](https://community.homey.app/t/capabilities-starting-with-measure-will-automatically-try-to-trigger-a-flow-what-to-define-in-the-app-json/20512/1 "2019-11-10T17:55:12Z")

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Reading below is awesome and save some work but what do I need to define in the app.json to make this work.

Thanks Edwin

```auto
## Starting Flows for custom capabilities

Custom capabilities starting with `alarm_` , `meter_` and `measure_` will automatically try to trigger a Flow. You only need to define this Flow trigger in your `/app.json` .

### Numbers

Calling `setCapabilityValue('measure_my_number', 1)` will try to start a Flow trigger with ID `measure_my_number_changed` , with a [Tag](https://apps.developer.athom.com/tutorial-Flow-Tokens.html) `value` .

### Booleans

Calling `setCapabilityValue('alarm_my_alarm', true)` will try to start a Flow trigger with ID `alarm_my_alarm_true` , with a [Tag](https://apps.developer.athom.com/tutorial-Flow-Tokens.html) `value` .

```

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<div class="post-metadata">

**Author:** ![Rocodamelshekima](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/rocodamelshekima/32/8209_2.png) [@Rocodamelshekima](https://community.homey.app/u/Rocodamelshekima)\
**Post date:** [November 10, 2019, 7:18pm UTC](https://community.homey.app/t/capabilities-starting-with-measure-will-automatically-try-to-trigger-a-flow-what-to-define-in-the-app-json/20512/2 "2019-11-10T19:18:01Z")

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Moved to Developers.

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<div class="post-metadata">

**Author:** ![MaxvandeLaar](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/maxvandelaar/32/18367_2.png) [@MaxvandeLaar](https://community.homey.app/u/MaxvandeLaar)\
**Post date:** [December 5, 2019, 8:37am UTC](https://community.homey.app/t/capabilities-starting-with-measure-will-automatically-try-to-trigger-a-flow-what-to-define-in-the-app-json/20512/3 "2019-12-05T08:37:49Z")

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Same goes for in the Device flow:

> If your driver has a _class_ that Homey already has support for, like _light_ or _socket_ , your custom card will be added to those cards. For example, if your driver supports a Light bulb that has a special disco mode, the user will see ‘Turn on’, ‘Turn off’, ‘Dim’, ‘Set color’, ‘Disco mode’.

I see the cards Turn off, on and Volume changed (I am working on a TV app) however they do not trigger the flow. The documentation could use an update with better examples in my opinion.