Hope this kind of ‘guide’ is allowed, took me quite a while to get it figured and sorted and there’s very little on google for my level (installed webcore 2 days ago) of knowledge.
How to integrate Hue Dimmer with ST and CoRe
Hue Dimmer to ST
Firstly you’ll want to add the Dimmer. Press the setup button on the back for 1 seccond. Start searching for a new thing in the classic app. It will eventually find it simply as a ‘thing’ set it up. It will not have any buttons yet but we’ll sort it soon.
Now, copy this groovy code from github and login to the smartthings graph api. Create a new device handler with the code you just copied, save and publish.
Go to "My Locations -> “Home” -> “List Devices” Click on the ‘thing’ you added on Step 1 and click “Edit” Change the Type to be “Hue Dimmer Switch (ZHA)”
Save and close. Now if you go into the classic app it should reflect you clicking the different buttons: ‘on pressed’, ‘up pressed’, ‘down pressed’, ‘off pressed’ If that’s the case then the hardest bit is done and it’s just a matter of replicating this piston and adjusting it to your needs.
The important thing to note here is the "Hue Dimmer’s last action is “on/up/down/off pressed” is when all the magic happens since this is what’s returned by the hue dimmer in a correct type to be compared. IF you use the “If button gets pushed” which sounds logical, then it will not work.