# Custom capabilities - rain in (inch) **URL:** \ **Category:** Developers\ **Created:** [May 26, 2024, 10:19pm UTC](https://community.homey.app/t/custom-capabilities-rain-in-inch/110546 "2024-05-26T22:19:13Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Arnt\_Soloy](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/arnt_soloy/32/58318_2.png) [@Arnt\_Soloy](https://community.homey.app/u/Arnt_Soloy)\ **Post date:** [May 26, 2024, 10:19pm UTC](https://community.homey.app/t/custom-capabilities-rain-in-inch/110546/1 "2024-05-26T22:19:13Z")
I’ve been trying to make a Weather Display app for Homey, and i have no problem make it work with a few basic units,like temp, rain , wind etc…and for these i have used the measure\_temperature, measure\_rain etc capabilities that Homey provides. Since i am using mm for the default rain, i am trying to make a custom capability for in (inch). Tried measure\_rain\_in, didnt work, tried measure\_rain.in, didnt work or maybe i just dont know how to add a sub capability. Whatever i try, it just returns invalid capability. A little help pointing me in the right direction would be much appreciated. Or if there is a more detailed guide regarding the Homey SDK ---
**Author:** ![Peter\_Kawa](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/peter_kawa/32/173848_2.png) [@Peter\_Kawa](https://community.homey.app/u/Peter_Kawa)\ **Post date:** [May 26, 2024, 10:31pm UTC](https://community.homey.app/t/custom-capabilities-rain-in-inch/110546/2 "2024-05-26T22:31:06Z")
Hi Arnt, > ![Screenshot_20240527-003025_Chrome](https://us1.discourse-cdn.com/flex025/uploads/athom/original/3X/0/d/0d8511550465a6f617d020aa553102372a618ed6.jpeg) Source: > **[Capabilities | Homey Apps SDK](https://apps.developer.homey.app/the-basics/devices/capabilities#sub-capabilities-using-the-same-capability-more-than-once)** > > A capability is a programmatic representation of a device's state. ---
**Author:** ![Arnt\_Soloy](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/arnt_soloy/32/58318_2.png) [@Arnt\_Soloy](https://community.homey.app/u/Arnt_Soloy)\ **Post date:** [May 26, 2024, 10:39pm UTC](https://community.homey.app/t/custom-capabilities-rain-in-inch/110546/3 "2024-05-26T22:39:10Z")
Thanks Peter, Might not have pointed out that i have limited knowlegde since i am totaly new when creating an app. I have looked at that example several times, but i just cant figure out how to use it, because as soon as i dont use the ones provided by Homey: [Tutorial: Device Capabilities - Homey Apps SDK v3](https://apps-sdk-v3.developer.homey.app/tutorial-device-capabilities.html) i get stuck ---
**Author:** ![Peter\_Kawa](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/peter_kawa/32/173848_2.png) [@Peter\_Kawa](https://community.homey.app/u/Peter_Kawa)\ **Post date:** [May 26, 2024, 10:57pm UTC](https://community.homey.app/t/custom-capabilities-rain-in-inch/110546/4 "2024-05-26T22:57:45Z")
I’m sorry this is all I know 😬 You can check the source of other apps, to ‘cheat’ a bit and move forward. F.e. search [github.com](http://github.com) Repositories for ‘athom’ ---
**Author:** ![Adrian\_Rockall](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/adrian_rockall/32/13209_2.png) [@Adrian\_Rockall](https://community.homey.app/u/Adrian_Rockall)\ **Post date:** [May 27, 2024, 1:12am UTC](https://community.homey.app/t/custom-capabilities-rain-in-inch/110546/5 "2024-05-27T01:12:15Z")
If you have already created a device in Homey then you will need to add the capability using this.addCapability in your device init function, but first check if it already exists. Just adding it to the device json file is not enough for existing devices. Alternatively, delete the device and add it again. Feel free to look at [GitHub - AdyRock/com.misol](https://github.com/AdyRock/com.misol) for examples. ---
**Author:** ![Arnt\_Soloy](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/arnt_soloy/32/58318_2.png) [@Arnt\_Soloy](https://community.homey.app/u/Arnt_Soloy)\ **Post date:** [May 27, 2024, 4:19am UTC](https://community.homey.app/t/custom-capabilities-rain-in-inch/110546/6 "2024-05-27T04:19:11Z")
Thanks Adrian, will have a look