Hardwired sensors

I believe someone (@wackware perhaps) have done something like that. Search in “Old Forums”.

Same here

I have 30 Windows
8 Entrances
3 Garage
about 10 smoke detectors

Would like these hardwire sensors to talk to ST

40 zwave sensors aint cheap

I finally connect all my hardwired sensors using –

Any updates on this? I would have expected that people would want a ST to replace/augment/enhance an aging alarm system. I have an 20+ year old wired home alarm system that’s beginning to fail. All the sensors are still working well and easily replaceable and I like the thought of not replacing batteries and wired systems are still inherently more secure and reliable than wireless.

My technical skill is soldering electronics not programming, so I’m more than happy to make up an ST Arduino shield to connect the wired sensors into the GPIOs but programming the Arduino is beyond my skill level.

3 door magnetic reed switches
2 PIR motion detectors

If upgrading to ST, I’d like to add in:
2 CO detectors
2 smoke detectors
1 garage door (Arduino SmartShield Garage Controller)

Idealy if this all fits back into the vacated alarm panel enclosure it would be awesome. If something like doesn’t exist, I’m willing to pay for someone write the script?

OR would it be easier to simply buy a new alarm system and integrate that into ST?


I’m the opposite :slight_smile: I’ve done hardware projects it the past, but I’m more comfortable writing sw than spinning my own PCBs.

Basically you have two options:

  1. Replace your old alarm panel with a new one that can be integrated with ST - either DSC PowerSeries or Honeywell Vista 20P. In both cases you’ll also need an Ethernet adapter for connecting the panel to the LAN and a computer to bridge ST with the adapter (they cannot communicate directly). This will cost you ~ $300 (panel and adapter), assuming you can reuse existing computer. There’s another solution using serial adapter instead of Ethernet and a gizmo consisting of Arduino, serial shield and ST shield. Cost is about the same.

  2. Rip out your old alarm panel and wire sensors directly to your custom built interface board. This should not be too difficult do design if you have time and skills. The question is how you connect it to ST. Arduino and ST shield is one way. Personally, I’d prefer a serial interface (RS232 or USB) to connect it to any computer, since I already have a server that runs 24/7.

I think a raspberry pi with GPIO board is the cheapest way to go. This thread is of great interest to me Raspberry Pi Device Type

I just did this with a smart shield and wiring directly to the alarm panel. (3 doors and 1 motion sensor to start). I went this way over the pi since the updates are pushed form the Arduino shield in real time instead of polled (which wouldn’t make much sense for a motion sensor). If we get UDP support, then that of course could change.

Oooh this is getting good… it really sounds like a shield and Arduino is the way to go. Works for me since I have an extra Uno lying around!

How were you able to provide power from the Arduino to the switches - more specifically the motion detector?

This may be a bit of a workaround but there is a Schlage door/window z-wave sensor that has the (undocumented) option to connect to an external relay (or sensor):

I used it to connect my hard wirded smoke alarms to Smartthings (through a relay).
Maybe you can bundle your wired sensors and use one of these for each of your alarm “zones”!?

Hey @pizzinini, can you share how you hooked up your hard wired smoke detectors? I’ve been wanting to integrate smoke detectors, but I can’t find any z-wave models that are hardwired. Your setup might do the trick and save me from replacing 6 detectors.Thanks!

You will need a relay for that. I have BRK smoke detectors and used this: BRK RM4 Smoke Alarm Accessory Relay http://www.brkelectronics.com/product/RM4
(I have seen that other manufacturers sell similar relays). The relay comes with a good description on how to connect it to your smoke alarms. Remember to use the right cables since hard wired alarms use 110v life wires. Since all wired alarms are interconnected, it does not matter which alarm you connect the relay to. The relay will have connections for an external device - that’s where you connect the Schlage door sensor (you have to take off the cover of the sensor and drill tiny holes in it to fit the cables though). I put the relay and the Schlage sensor in a nice plastic box from Homedepot so it looks clean.

I hope that helps!


Thanks! This is perfect, and simple. I have First Alert detectors, and the BRK relay says it will work with them. Score! I appreciate your effort in getting the info so quickly, and for the graphic. Cheers!

Vijay - how do you want to integrate these? By zone? By type? There are a lot of ways you could do this without an individual sensor for each… Do all the wires come back to central location or are there remote wiring boxes/locations?

In my case, it is an existing 12 volt system and I was getting the existing hardwired devices in to the arduino to then push into the Smartthings ecosystem upon an event change. I just used a voltage divider (and later added an optoisolator to protect the shield) into the pins at 5volts.

Please share how yo u did this?

I would love to hear what solution(s) everyone has tried and what was most successful. I have an existing system that has wired door sensors and then several wireless windiws sensors (undocumented details so I’m not sure what frequencies, protocol, etc) . I was thinking some arduino that detects fluctuations in current for the sensors OR maybe even go the root of breaking open the control panel and having the arduino detect the variance in current on the lights on the panel that show what zones have “trouble” and if those are lit, then the zone is not secured. This leaves the existing panel in place and also allows me to integrate into ST. I have some programming experience but zero circuitry and only enough soldering experience to get me in trouble.

Any recommendations would be appreciated!

Take a look at Monoprice’s ZWave door sensors. They too have an external switch option. In theory this could be wired into a zone on your alarm panel.

Im ordering one tonight; and will update with it’s application.

@Mihos - Any chance you might be able to do a quick write up for your project? It sounds like your implementation is exactly what I am looking for .

You may need $11.9 Arduino Can-Bus Shield here: http://www.elecfreaks.com/store/canbus-shield-p-746.html