I made a Homey app for SG LEDDim dimmers and other SG Smart products: the rotary dimmers, LEDDim Smart 3.0, Smart Pill, Smart Plug, Smart Socket and HeatReg Smart. So far the first-generation dimmers and LEDDim Smart 3.0 are confirmed working.
Homey connects directly to them over Bluetooth, so no SG gateway is needed.
LEDDim Smart 3.0 is supported from 2.8.0, now on the test version. It needs a login with your SG account in the app settings.
You can add the devices one by one. First-generation dimmers can also be added as a group from the SG app and controlled together.
If a device doesn’t respond, log in with your SG account in the app settings to fetch the network passphrase, or try 1234 in the device settings.
This is unofficial and has nothing to do with SG. A lot of the protocol work comes from nkaminski, fromm1990, einaros and erlwes, and for SG Smart 3.0 from Fredrik Karlsen, David Simon and shejnowicz.
Code and issues:
2.0.9: Group device fixed
2.0.10: New icon and app image
2.1.0: Keep dimmers connected
2.4.0: Faster status, signal per dimmer, better pairing
2.4.1: Fixed a bug that could stop dimmers responding, warning on wrong password
2.6.1: Newer LEDDim generations, Smart Plug, Socket and HeatReg
2.8.0: LEDDim Smart 3.0 support and optional SG account login (Test)