So I moved into a new home and it is pre-wired with door/window/motion connection points. There are no actual sensors or panel just the wiring and I was wondering if someone could point me to the best way to utilize the wired system and smart things.
Ive spent hours and I can find the best way to go about it yet. I have an Arduino sitting around that I could use to wire the contacts to but again not sure how.
@ogiewon might have some ideas. 
Thanks for the tips JD. My thinking though is that why constantly replace batteries when its already wired. If i could just power it and have it attached to the Arduino to send the signal then why not. I have a panel in a closet where the full alarm system would go so im thinking the Arduino would fit nicely there out of sight.
Most devices will last at least a year with batteries.
It may be easier to use a system designed for hardwire and integrate it into ST. Using something like thingshield with Arduino will require a fair bit of work.
Take a look at my ST_Anything project. I did the exact same thing as what you are proposing, and even automated my garage doors as well. I bought very inexpensive magnetic reed switches on Amazon to connect at each door using the alarm pre-wiring in my house. I bought them on Amazon. In the case of my house, the door opening were pre-drilled for the sensors with the wires just tucked inside each hole. Super simple to simply pull the wire out of the hole, attach the sensor (pay attention to proper diameter), and then push it into the hole. The magnet portion is simply installed in the edge of the door after drilling an appropriate sized hole, and pushing it in. It takes less than 15 minutes per door once you get the hang of it.
So, i was able to connect 4 house doors and 2 garage doors to ST for the cost of an Arduino UNO (or MEGA 2560 preferably), the ST ThingShield, a power supply, magnetic sensors, and relays (for the garage doors.) No batteries to change, ever!
In my github repository (and discussed on the following thread), you will find numerous examples of how my library has been used to integrate many different things with ST using an Arduino. Home alarm projects are the vast majority, so you should be able to get things going quickly if you choose this path.
Your a king amongst men Ogiewon! 
Thanks to you I will have this up and running by next weekend! Cheers 
Would you have example of wiring? I have 5 magnetic sensors i want to start with. Im more of a software than hardware person. lol
These are the strips i was looking to purchase. I notice they are normaly open type. Will that matter?
If you use one of my sketches, they are all set up to use the Arduino’s internal pull-up resistor. This means that each digital pin used by the sketch as a “contact sensor” will have 5 volts on it by default. When you connect the digital input pin to the Arduino Ground pin, the sensor will register as “closed” - meaning the door or window is closed. When the connection is broken, the door or window will register as “open”. So the wiring through the switches you purchased is very simple. Just connect one lead from every sensor to a common GND pin on the arduino (I use a small breadboard to make this easy to change as necessary) and the other lead from each sensor connects to a corresponding digital input pin on the arduino based on what pins you choose within the arduino sketch.
If all you want is to monitor doors and windows, take a look at my ST_Anything_Doors_Windows.ino example in my github repository. If you want to add some of the other capabilities that I have implemented, like temperature/humidity, luminance, motion, etc…, take a look at my ST_Anything.ino example.
Note, pay close attention on how to wire up the Arduino to the ThingShield if you decide to use an Arduino MEGA 2560 (recommended if you have a large number of sensors you want to use.) Using my ThingShield library with the MEGA, you’ll need to add jumpers between pins 2 and 14, and pins 3 and 15.
One thing you will need to understand (and I am glad you’re a software person) is that you’ll need to utilize one of my “Mutliplexer SmartApps” to allow you break out each window/door into its own SmartThings “Device”. My multiplexer apps keeps “virtual devices” up to date, thereby allowing normal ST SmartApps to see each door and window as a single device. This is necessary since ST does not support having a single device with more than one of each “device capability”. My ST_Anything.ino implements one of each capability. The ST_Anything_Doors_Windows.ino example implements many “contact sensor” capabilities. For each and every “contact sensor” you define in your arduino sketch, you’ll need an entry in a Multiplexer app, and a corresponding virtual contact sensor device (manually created, as I haven’t figured out how to automagically create child devices of a SmartApp yet.)
Hope this helps. Have fun!
Dan
I just finished a very similar project! I was very interested in @ogiewon’s Arduino project, but unfortunately the ThingShield is no longer available and I couldn’t get my hands on one. Instead, I went with a NodeMCU ESP8266 board with built in wifi. The ST_Anything project was a great inspiration, but with the NodeMCU it communicates directly to ST API over your wifi connection, so the flow of information is a bit different.
Overall I’m very happy with the setup and low cost of the project. Works like a charm.
I wrote up some details of the project here and there is code linked on Github: Connect wired alarm system sensors to SmartThings with a NodeMCU ESP8266 [deprecated]
Hi sorry for sounding like a newbie but I’m looking at doing something similar I have a wired alarm system and I would like to integrate it with smartthings I’m hoping to be able to remotely see if it’s armed, arm It, disarm It, and be notified if it’s triggered. There the main points I want anything else would be a bonus. I’m thinking things may have changed since this thread was started. My smartthings knowledge is pretty basic but my wiring skills are good and I pick things up pretty easy but any help would be appreciated.
Thanks
Hi @frazhd2, I’m a newbie here too but am also looking to integrate my existing alarm system into SmartThings and have been researching this recently so thought I’d share my current thinking, a) in case it’s still helpful to you, and b) in case anyone offers further advice for either or both of us.
I am currently trying to decide between one of these two approaches to the project:
Use the Konnected Security 2.0 system by @heythisisnate (who posted above) whose early project seems to been so popular that he turned this into a product and sells the kits, which I think is just awesome! This solution has hardware based on a NodeMCU (a single board microcontroller) each of which can handle up to 6 sensors (door, contacts, smoke alarms, etc) and you can have multiple units if you need them talking to ST over WiFi.
Use the ST_Anything setup from @ogiewon (another ST super-user who also posted above) also running on a single board microcontroller, in my case I’m going to try the relatively new ESP32 which I believe can accept more sensors than the NodeMCU.
Both these solutions use the Arduino development environment which I’ve just started to look at today. Both have excellent documentation too and as a newbie to the world of ST and microcontrollers etc I am staggered at the level of quality and support of community build solutions like these. I’ve never heard of Arduino or plugged anything into a circuit board until last week so could be wrong on just about all of the above (please forgive newbie errors) so read the many great posts of the gurus mentioned as they seem to know alarm systems & ST inside out!
ST_Anything uses the Arduino IDE. Nate’s Konnected solution does not. I believe his solution is based on LUA.
I definitely feel the Arduino IDE has many advantages as the same code can be run on many different micr controllers. Also, there are tons of examples on how to integrate various devices via the Arduino IDE and associated Libraries.
Thanks for pointing out my error and Arduino seems amazing (apologies for newbie “first visit to sweetshop” enthusiasm for everything by the way!).
I’ve decided to try your ST_Anything route as although there is a steep learning curve for me, that’s part of the fun and the end result should give me exactly what I’m looking for. Seems I just need to learn about Git, Arduino and breadboards for starters if I’m going to be able to do anything with this scary looking ESP32 board 
Fingers crossed…