That’s because we have perverted the use cases of “Simulated Devices” far beyond their original purpose…
i.e., They were meant solely for testing SmartApps.
So, in order to provide a comprehensive test suite, every “Simulated Device” should mimic as many capabilities as a “Real Device” as possible, including, obvious or not … Health Check.
I changed all of my virtual switches over to the ones created by the st app. I haven’t been seeing any problems.
I changed the Simulated Switch devices to the Virtual Switch DH and everything functions as it did before. Haven’t seen any new issues created by doing it either so it seems the easiest fix.
I’m not sure if this helps or not, but my issues with Alexa and simulated switches started about two days ago as well. However, I have Google homes throughout my house as well and they aren’t having any problems controlling any of my simulated switches. I prefer to use Alexa for voice control and I have a lot of simulated switches in my setup and really would rather not re-create them if at all possible.
I’m guessing they deprecated simulated switch and dimmer for virtual switch and dimmer.
Just login to the IDE and change the device type to virtual switch instead. You should be good to go as others have reported.
Thanks for reporting this issue everyone. We are looking into it but as others have stated the Virtual Switch and Virtual Dimmer Switch are good permanent replacements for the Simulated Switch and Simulated Dimmer Switch with the added benefit that they can run locally on later versions of hub firmware.
When looking at the SmartThingsPublic repo in github be aware that the production branch is the code that has been released to everyone. The master branch and staging branches are used for our internal testing prior to releasing to production. This is the version currently in production: https://github.com/SmartThingsCommunity/SmartThingsPublic/blob/production/devicetypes/smartthings/testing/simulated-switch.src/simulated-switch.groovy.
I’m not sure why health check support was added to these simulated device DTHs (I’m just a Zigbee guy) but from looking at the changes it looks like the devices are supposed to always be online. Perhaps that isn’t working as intended and that’s what is causing the issues with Alexa but I don’t think the intention is for the simulated devices to ever be offline.
Thanks for the inside “chime-in”, @tpmanley!
It looks like the last commit to the production branch was 10 days ago, which makes it less likely this commit is the root cause (since it would have been discovered sooner…) … But oh: I guess there’s a lag between commit and deployment!
Do you know when this commit actually was rolled out? Was there a platform update just in the past few days? Then this commit would the key suspect, right?
(And I think it’s cool that I’m among the few developers who’ve contributed to this DH code 
… about 2 years ago. Darn that it may be deprecated soon, as I was enjoying the royalty checks! 
).
Those changes were released on 6/12 so certainly could be related.
If it helps, my “Bedtime” virtual switch stopped working via Alexa while I was away on vacation. Eventually I figured it was because as well as lights etc., it changed the security status from disarmed to armed (stay) when turning it on and vice versa turning it off in the morning. The switch still works from the ST app. It’s a disappointing pain, but I can understand the security need.
These changes have been reverted and simulated switches should be working with Alexa once again.
In simple for a noob to understand terms, is simulated better than virtual switches? I just changed simulated to virtual, when the simulated stopped working. There are just 18 of them, it doesn’t take long to change them back.
No.
10 chars.
Main benefit is the “virtual” ones run locally and as stated, are the newest versions.
Thanks for answers I understood.