Question about no-frills integration with existing alarm system (Vista-20)


I had a quick question regarding integrating Openhab with an existing ADT installed Honeywell Vista-20 alarm panel.

I know there are a lot of feature rich adapters (ie AlarmDecoder) that will let me control and gather all the information from the Vista-20 panel. However, what I would like to do is much simpler. I will still arm/disarm the system from the current keypad- all I want to do is remove ADT from the loop and have Openhab alert me whenever the alarm system is triggered.

It seems I could use a relay on the Alarm Output pins (#3 and #4 - 10.5 - 13.8V 2A Max) and use it to simply trigger an input pin on an arduino node. This of course would run through Openhab and send some kind of notification to me.

If I wanted a no-frills notification when the alarm system is triggered, thereby cutting ADT out of the loop, does this sound like it could work? Or is there something obvious I’m missing?

Just to be clear, I do not care about knowing what zone triggered the alarm, or remote arming/disarming via smartphone, etc.


-Mike D.

Yes a relay would work, allowing to you to choose from a whole range of ways to get a ‘contact’ type input into Openhab.

Adding a means to notify yourself will not alter whatever it is the alarm does to notify ADT, so that won’t “cut them out”.

Why not add a second relay that indicates when the alarm is armed, for peace of mind you could check it remotely. (and allows Openhab to do different things e.g. with lighting)

If you want a simpler way without relying on Openhab servers, networks, blah … just get a phone or GSM dialler and link directly to the panel. You want an alarm to work reliably!

This all sounds promising! I wasn’t clear about cutting ADT out of the loop- that would be accomplished by A) cancelling their service, and B) disconnecting the phone wires in the alarm box.

And good points about reliability and arming status. I do have a bit more to figure out, but didn’t want to start planning those later steps if the base idea wasn’t sound to begin with.


-Mike D.

For an example, at our business premises there are separate conventional intruder and fire alarms, and Openhab.
We’ve chosen a voice message GSM dialler with multiple wired trigger inputs, delivering voice and text messages from burglar or fire alarms. It is set-up and forget, no intervention required after install.
Spare triggers allow the dialler to pass a small number pre-defined ‘interesting’ event messages from Openhab rules - e.g. doorbell is rung while alarm was armed.

This all works properly still in case of power outage, broadband outage, server crash, phoneline cut (we’re on overhead wires), My.Openhab outage, DynDNS problem, blah.
It would not survive a mobile network outage - if that seems possible diallers are available that handle both landline and mobile as fallback.

If your home/business justified a “proper” alarm system, you probably want to maintain that level of integrity.

The missing factor that ADT currently presumably provides is a keep-alive check, a reassurance that the basic alarm is alive and well at all times.