Using existing Home Security System (Honeywell, Vista, etc) Sensors with Smartthings

So like many people I have a Security System already wired into my house. Door sensors, window sensors, Motion detectors, etc.

When we moved in I played around with it and figure out the code to use it; but never had any intention of hooking it up to ADT or any of the other security companies.

As I’ve been getting deeper and deeper into HA, it’s always bothered me that I couldnt figure out a way to utilize those existing sensors in my SmartThings environment. Why buy new wireless motions, door sensors etc, when I already have a great setup of wired ones in place?!

When browsing around for solutions, I noticed that many of the Z-wave door sensors have an external sensor port; where you can wire an external sensor into the Z-Wave sensor.
My logic was, why not just use this external port to send the status of my wired sensors.

So I ordered a Z-wave door sensor from Monoprice, and tried it tonight. After some playing around, I’ve got my wired sensors sending a status to the Z-Wave door sensor, which then updates the hub.

Step 1: Add wires to the external sensor port of your Z-Wave door sensor
Step 2: Connect wires “before” the diode to the hardwired sensor you want to connect to (before the diode means on the sensor side, not the panel side) This is important, in testing it did not work when I clipped my leads to the “panel side” of the wires, I am not an electrician, engineer, or have much (any) electronics background, but apparently the diode is necessary to isolate the sensor
Step 3: Test it.

You can see in the pictures below the wiring diagram for my security system, the alligator clip leads to the z-wave sensor clipped onto the hardwired sensor wires, and the z-wave door switch sitting on top of my alarm box.

Now I just have to use a smart app to notify me when there is a status change, motion, etc when there shouldn’t be.

You will be limited by the “zones” on your security system, and will need a door sensor for each zone; but there have been good deals on 4packs lately for these


You can make a custom interface using an arduino and a smart things sheild.

Alternatively, Fibaro has a universal binary sensor that can take two inputs (zones) each.

I was really interested in the Arduino idea; but honestly I’m no programmer, and just dont have the time I’d like to tinker enough to figure it out. I will take a look at the Fibaro binary sensor though!

@bryanphaas, this is interesting because I want to do the same thing. I want to keep my hardwired devices (supervised) connected to my panel and at the same time use them in ST.

I use the Ecolink sensors (same as the Schlage) that have terminals inside for hooking up wires, but I’ve never got mine to work with ST and my Vista panel at the same time. It was either the Panel or ST, but never both. I could have sworn I hooked them up the same way you did, but now you got me thinking. The difference for me is that the resistor is at the end of the loop at the sensor, not at the panel like your pictures show.

The Fibaro sensors would allow dual use.

That said, it seems to me that enough people have this ‘problem’ that a commercially available device would be handy.

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Yeah, that’s a nice sensor. I wish I would have seen that a while back.

Just a bit of a warning to anyone who considers doing something like that: you’re most likely to damage your door sensor. The sensor’s auxiliary input is not galvanically isolated and is only intended for “dry” (i.e. non-energized) circuits. The alarm inputs can carry as much as 12V potential which far exceeds sensor’s 3V voltage.

I am not an electrician, engineer, or have much (any) electronics background,

Yes, obviously. :smile:

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replace your alarm with a honeywell or dsc system and integrate it with an evl-3 module. you can buy a full system including keypads for around 200 bucks and the evl-3 is 100. for the alarmserver app it requires a pc on 24/7 to monitor your alarm, but thats a small price to pay to be able to arm/disarm automatically based on events, or to use all of your home alarm sensors, contact, motion, and smoke.

not to mention home alarm system contacts, motion, and other sensors are way cheaper and you gain double benefit from them as they are monitored by a UL approved company and you can use them on ST.


for existing system there have been some great projects and implementation of DCS and Honeywell panels (including ADT) using arduino or Envisalink 2/3 successfully. I wish it were simpler to implement as i am not a programmer either but there are some pretty helpful folks on the forum.

I am working on setting mine up now using ADT Honeywell vista 20p, raspberry PI B+ running alarmserver and my home theater screen as the largest programming screen for a PI i can come up with…

Best of luck

I know this post is a few months old but I am looking to do exactly what you are describing. Could you give me more details on how you made it work what all I need? Thanks in advance!

search github for @thomasii code and open the ports on your firewall. you need a 24/7 server running his custom alarmserver code to receive/send information. basically your setup will look like this…

EVL-3 -> alarmserver on pc ( i use raspberry pi) -> ST cloud -> smartthings hub -> ST app

the hardest part is getting alarmserver configured (test via publicIP:port) to make sure you can get to alarmserver from the public internet, and then doing oauth to approve your switches and smartapp that ethomasii uses.

Just an FYI there are a number of people (my self included) who have fully integrated ADT Vista 20p panels into STs and are able to fully mimic a controll panel in STs. I’m on an iPad right now so I can’t link threads but before everyone reinvents the wheel you should take a look.

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Thank you for the reply. Are you able to use wired motions and wired door/window sensors? If you do how fast is the response time? My end result is to have lights work automatic, but also I want a fully integrated security system that is armed and disarmed with out the need for me to enter a code every time. The easier and more user friendly the better, my WAF is kinda low right now and this will raise that. Do you use a smart app to control the Vista? Do you have a device setup in ST?

It’s def. not as quick as a direct system but I find that things react within 1-2 seconds in the worse of situations.

I’m able to fully disarm and arm my stem in away or home mode. I also made it so I can turn off chime, disable zones, etc. Basically anything you can do from a keypad I’ve created keys to complete the macro for me.

Can you share details on this with a noob in mind?


I am using my old Vista system, as in it still works. Thus I take the Alarm out signal use that to trigger a door sensor into SmartThings. That is actually a very simple solution. Basically the Alarm out from Vista triggers a relay to connect into the Door sensor. Actually I currently use the Alarm out to feed a Lorex Security camera system. The Lorex will email me a picture when trigger. And with the lorex I can access it over the web to se whats going on. So I should say I will also add it to a door sensor such that SmartThings can be involved. Basically SmartThings just knows that my alarm panel trigger. I then use then can check the cameras to see the cause of the trigger.

Maybe this solution has been discussed and is old news. If not and someone wants a diagram I will draw it. BTW at the beginning of this thread those are not diodes, they are resistors.


You’re right, this is the most basic and simple way to integrate alarm panel with ST. It’s been suggested before in several related threads. See for example,

Most alarm panels have two programmable IO terminals. You can also use the second one to tell ST when the alarm is armed (output) or you can have ST to trip your alarm (input).

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I was wondering about this, and thinking isn’t the Honeywell IP module doing the same thing as the evl-3?
I have a Vista20 that is already on the local IP network through the dual path communicator.

Does anyone have any experience using this type of connection?


Please forgive my ignorance here, what is the alarmserver app for PC?
Where do I find more info on this?

Aarmserver is python program that can run on a lot of stuff. PC, raspberry, and even Mac I believe