At the present time, the only way to control SmartThings-controlled devices that are not made to work with HomeKit is to set up a separate server and run some software that will make HomeKit think everything is coming from a Phillips hue bridge even though it is not. So basically you are building a fake virtual hue bridge to fool HomeKit. That is what “homebridge” is. It requires quite a bit of technical skill to set up.
You can’t use a real Phillips hue bridge and achieve the same thing, because you can’t connect your other SmartThings – controlled devices to it. So the real Phillips hue bridge is not a workaround for this.
The other alternative: only use real devices that work with both SmartThings and HomeKit
The other alternative, which is what we do at my house, is to only use devices which will officially work with both HomeKit and SmartThings.
There aren’t many of these, but there are some, and it may be enough depending on what you are trying to accomplish.
For example, Lutron Caseta light switches will work with both as long as you have the Lutron SmartBridge. Smart bulbs connected to the Phillips hue bridge will work with both. The ecobee thermostat will work with both. And the August pro smartlock will work with both.
So it just depends on exactly which devices you need, but if you can limit yourself to the ones that work with both, you won’t need any special code or to fake anything. It will just work.
There is a list in the community – created wiki of devices that will work with both. Again, it’s not a long list, but there are some.
As far as limitations, if you are only using official devices you won’t be able to trigger routines or use virtual switches. It is possible to use actual physical devices like Hue bulbs as a "man in the middle because both HomeKit and SmartThings will know when that bulb is turned on or off. So it just depends on what you want to accomplish as to whether this kind of integration is possible.
For example, you could have HomeKit turn on a Phillips hue bulb and have that Phillips hue bulb turning on cause a routine to run in SmartThings. That might be fine for some use cases, but not for others.
Thanks, that’s makes it much clearer.
I have what I started with Verizon when they dabbled a long time ago.
Trane Thermostate & aeotec sensors.
Then over time added GE Dimmers and add -ons along with some motion sensors and GE outdoor switches.
Looks like the software route for me. I can probably trudge through it.