There is this which will work for any smoke detector..
Or if you wanted to have some tech fun - set up a homebridge/Node-RED server and you can detect events from Nest devices. Currently am testing skew temps on my thermostats and sending an alert if out of bounds. Also syncing my infloor heating pearl therms with my nest therms.
Thanks, I'll take a look at the Ecolink.
I'm trying to keep NodeRed out of my network because it's just one more thing on the network, so I'm trying to find stuff that talks directly to HE.
Well I use Node-RED and Homebridge not only on my system but also on my residential clients. Works really well and I think reduces a lot of overhead on the HE Hubs which is nice. Of course it's not for everyone...
Here is a screencap from my Homebridge server:
edit: I should note that my Node-RED / Homebridge setup does not require any Apple stuff at all..
Check the manufacturing date. The older generation Nest Protects brick themselves after just 7 years, In fact, mine did so three months prior to that.
What I'm saying is that you need not regret your purchase too much. You probably would be looking at replacing them soon anyway.
Yeah, I've used NodeRed in the past, it definitely has its place, I'm just trying to avoid it if I can because I want this to be as "hands off" as possible.
If I can't find what I want then I'll come back to node red, but the Ecolink looks reasonable...
Exactly my reasoning FOR using Node-RED 
Once set up it just keeps working - in fact I have not really had any issues with the memory/app resource usage that some have been experiencing.
I decided that for my use-case (and my clients) this was the optimal way to go - more flexible, robust and stable. My first system to incorporate these companion apps went in last August and I have now deployed several others.. so far has worked out very well.. 
but ymmv....
Why use home bridge if you don't use apple?
I actually do use Apple now but when I started I did not. Homebridge gave me a way to use Ring and Nest products in Node-RED (and HE). For example I trigger an old Aetoec Siren when the Ring Doorbell is pressed.
For my clients since in my setup Node-RED and HB live on the same server I like to be able to offer Apple Home connectivity for non HomeKit devices... A lot of my clients are Apple-centric.
You can continue to use your Nest protect with a Homebridge plug-in if that works for you. I have four protects and personally don’t think there is a better designed sensor available. Wouldn’t trade them for any kind of convenience. Fortunately, with this Homebridge plug-in, I don’t have to.
And if I’m not mistaken, there’s also a community Nest app floating around here that also supports the detector cloud connection.
It’s also possible to trigger virtual switches on HE from Home Assistant, and that’s all you need for triggering HE rules. HA has Nest Protect support as well.
Thanks, I've got the current Nest plugin that uses the Device Access | Google Developers setup, but that doesn't support Protect, just the cameras, thermostats, and home hubs.
I'll take a look at the home-bridge stuff, as with NodeRed it feels like I shouldn't have to run something else on my network to bridge this, but at the same time the blame here lies fully with Google, not with Hubitat... 
You might want to look at the My Next Manager product. It does, however, require a "donation." Setup is not simple, but it seems to work well.
This is honestly is just the state of home automation. Hubitat supports a lot of devices directly, and you can certainly stay within those boundaries, or you can give in to bridges and just run them.
I prefer the versatility of bridging. I bridge with two always on MacBooks (a 2011 MB Pro running Node.js for Homebridge and other dedicated Node.js apps, and a 2009 that runs HA just for bridging specific devices). I also have a Hue bridge. My weather station has a bridge. My Insteon stuff is bridged. My Aqara buttons are bridged via an Aqara hub and HomeKit. My Pico buttons are bridged. One of my door locks is bridged to my Apple TV to get it into HomeKit where that is bridged with Hubitat via Homebridge. My Deta kitchen tap is bridged to HE via Alexa.
Bridging doesn’t have to mean unstable. All of these bridges open up opportunities for getting cool and useful, often low cost, but high quality devices into HE. This for me personally, makes home automation fun.
That HE/HA stuff looks very cool. Sadly cannot incorporate HA into my clients systems as there is just too much tweaking/support involved. For personal use and experimentation - oh yeah!!!!
Also not mentioned that since these systems are opensource you have the ability to directly control various aspects of the setup including memory/storage/processor etc. Even possibly modifying the code if you are up for it..
Well, my personal experience so far with that, admittedly only a few months, is there is no tweaking. It's a device bridge for me. Other than updates for security concerns, I have no reason to even look at it. I haven't used it for any cloud integrations other than my weather station at this point. I'm using it for a ConBee 2, which gives me rock solid and fast performance of Xiaomi devices, and I moved my Sonos over there because the ConBee holds onto the IKEA Symfonisk controller nicely and doesn't require the same Rule Machine/Button Controller/ABC gymnastics to make the device work as a Sonos controller as direct pairing it with HE does.
However for commercial applications, I think open source just generally is a questionable choice to make. So for that primary reason, I'd agree that adding HA into the mix probably isn't the right decision.
It wasn't until Google took away the Nest API's 
I've used OpenHab, LightwaveRF, and HomeAssistant in the past and the thing that really appealed to me about Hubitat was that I wouldn't have to worry about whether the container was running or the SD card in a raspberry pi was still viable (both of which have bitten me with HomeAssistant and OpenHab), and I'd be able to do more than just control the lights.
Zigbee/ZWave support give me 90% of what I need, Hubitat community plugins mean I can control my TV, XBox, Lights, Sonos speakers, get presence data from my Unifi Network kits, and even keep an eye on my 3D printer from a single hub, and the drivers available for the Acceso al dispositivo | Device Access | Google for Developers stuff mean I can control my heating as well, I just can't generate events based on my fire alarms any more.
Hubitat had this functionality in the past, Google has taken it away, and I'm struggling to find an alternative that doesn't involve me strapping stuff together.
I do enough software development and infrastructure maintenance during my day job, I don't want to do that stuff at home, I just want a solution that works for my (reasonably non-technical!) family and myself without having to troubleshoot stuff constantly - Hubitat is that solution that's halfway between HomeAssistant and Control4-style options, and I'd rather dump the Google stuff and find an alternative than start putting in more devices running extra software that I shouldn't need in the first place! 
Well we're getting into personal opinions here. 
My personal opinion on that subject is we never really had much to lose. We all complained about it like we were losing more than we actually were. It's a cloud connection. We never actually HAD that, but rather it was offered to us. Local is the only thing we will ever HAVE, that cannot be taken away from us.
I didn't my buy Nest Protects and go, "Oh cool, a WiFi connected cloud device! 
" 
Free smart home integrations like that are dealt to us, not won by us. 
Of course we are, this is the internet, it's compulsory... 
True, and one of the key reasons I wanted to go down the Zigbee/Hubitat route in the first place.
I think this is the key difference between us here, I bought them on the basis that I would get notifications sent to my phone if I wasn't in the building and that they would integrate with my home automation systems (which they did at the time!), and when Google bought Nest I believed them (perhaps naively!) when they said that the API's would remain.
Had I known back then what I know now, I would have gone for an all-zigbee/z-wave solution, or perhaps not bothered with the at all and just gone for three "standard" ÂŁ10 smoke alarms rather than 3 ÂŁ90 smart ones.
Stuff like this influences my purchasing decisions, nothing is bought on a whim "just in case it works out" because I can't justify doing that, so to have functionality taken away from me when it was expressly part of the reason I purchased something is absolutely something I'm going to get upset about!
*Edit: * One of the most frustrating things is that I was actively encouraged by google to switch from my Nest account to a Google account, and had I not done so I would still have that functionality! 
In fairness, for which they don't much deserve based on their track record of just giving up on pretty much everything, they did keep that going for many years, which in "Google years" is considerably longer than Gregorian calendar years. If anybody got screwed, it's google by themselves. Can you imagine how much their industry peers still laugh at them for paying 3.2 Billion dollars for Nest?
actually laughed out loud at this, a very good point...
Download the Hubitat app
