[SOLVED] Best Smoke/CO Detector

Simple question that I don’t see in the forums.

What is the best and easiest Smoke/CO detector to use with Openhab. It needs to come in wired in version.

Looking for ease of setup and quality of the detector itself. Don’t care to much about price but don’t want to go crazy either.

I currently use mostly Insteon products and would like to not have another hub but that would be okay if necessary.

If you are using Insteon products, as I do, then the First Alert Interconnect is a good choice as it interfaces with and is the only brand supported by Insteon. Coincidentally I just replaced all of my smoke and CO detectors with the First Alert System and interfaced it to OpenHAB via an ISY994, the Insteon Hub would work as well. Now the only hitch is that Smoke/CO detector(SCO500) is battery only, not wired. The smoke only detectors are wired (SA520). I have installed both in different locations throughout the house depending on need. You will need only one Insteon Smoke Bridge to interface to the hub/plm and only pair 1 Smoke Detector to the bridge, as the the First Alert detectors all interface to each other. When 1 sounds they all sound.

A couple things to note, the communication is only 1 way. From the Smoke Detectors to the bridge and then the Hub and then OpenHAB. You cannot digitally send a signal to the detectors to sound an alarm. It didn’t take much to install, but I did spend a bit of time reading the Insteon and ISY forums to make certain I understood the limitations and benefits of the system.

One final word of caution. You cannot use the newer style, square First Alert ONELINK detectors with Insteon. Only the older style round/octagonal will work.

Check the NEST Smoke detectors. Easy to setup, familiy friendly alarms and function tests not just a stupid sound. We love them

Support for Nest in openHAB is on the chopping block. It was originally set to be killed by Google back in August but they’ve extended the deadline. But at some point, we will lose access to Nest. New users of Nest already cannot integrate Nest products with openHAB as they have closed down access to the Works with Nest API to new users. For this reason, I cannot recommend Nest products.

Thanks, Are the SA520B and SCO500B equivalents?

Yes. As far as I could tell they are equivalent. It gets a bit confusing because there are models and sku that refer to the models and get used interchangeably. For example SA520 model has an SKU SA521CN-3ST. I used the SKU when I made my purchase. From reading the ISY forums, the 3ST in the sku insures it works with Insteon. Same goes for the SCO500.

Not sure. We’ll loose access as it is but Google is creating a “device access sandbox” for individual use. I also may be able to control the thermostat via the Amazon echo binding (beta version). I can already see the current temperature.

I’m not holding my breath that that will be available before they close down the Works with Nest API. They’ve already stated and continue to assert that a project like openHAB will not gain access to the Works with Google API so at a minimum I predict there being a pretty significant gap between when we lost access and the new sandbox access is created.

The binding will also need to be rewritten to that new API. Access through Amazon might be an option for some who already use Alexa, but if someone is choosing a product right now, I still cannot say I recommend starting with Nest. Of course that opinion could change in the future when/if Google ever gets their act together.

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If you can live with wireless connectivity, I’d suggest to take a look onto the Homematic family with the HM-Sec-SD-2 devices.

Xioami and honeywell do one in partnership which I believe (but not tested) should work with the xioami plugin.

Heiman makes both CO and Smoke detectors. They work with DECONZ and Zigbee2MQTT.


why not a DIY? I’m running a ESP2866 (Wemos D1 mini) with MQ5 sensor hooked up to ADC A0 pin. Software is ESPEasy which does the MQTT communication just fine. Works like a charm!


Would your insurance company be happy with a DIY smoke sensor?

Not only insurance but related, in many locals in the US at least, a DIY smoke detector would not be to code. Also, are you sure the MQ5 is right? According to the page you link to the MQ2: Combustible Gas, Smoke and MQ9: Carbon Monoxide, Coal Gas, Liquefied Gas would be required to build a Smoke/CO detector.

Also, the warning on the page indicates the sensors only indicate the over all trend of concentration, not the overall concentration. Would this sensor go off if the concentration of CO grew very slowly?

Hi Rich,

certainly it depends on what one wants to achieve. I was pointing out a DIY way because it can be done. In my case I have “hacked” a commercial dumb smoke detector by adding the MQ5 + Wemos D1 mini for gas detection and make it a smart sensor.

The MQ5 has a digital output with an adjustable threshold. When the sensor analog output is exceeding the threshold, the digital pin switches. So a slowly raising ppm level will trigger eventually.

I’m not claiming this being a perfect solution. It works for me and my purpose.

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From this discussion, can I conclude that the First Alert ZCOMBO should not be much of a problem to connect to OpenHAB via my AeoTec z-wave stick?

UPDATE: I can now confirm that both First Alert and BRK SCO500B and SA520B will work equally well with Insteon Smoke Bridge.

It won’t be a problem but it definitely doesn’t meet you “wired” requirements. Also, it doesn’t support association groups beyond the controller and you can’t send commands to the device so there is no way to, for example, have them all go off when only one is detecting smoke.

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Well I’m not proficient enough with z-wave to know what I would do with “association groups”. I think that all I want is to send a text message and email when the detector signals a problem.
I already have my system set up to send texts and emails if any door or window is opened. I am hoping I can add these to the text/email event list.
I hope, I hope, I hope.

It’s the association groups that would allow the detectors to talk to each other. But obviously, the alarm will make it into OH as an event where you can do with it what you will.