Alarm Integration the DIY way

by milneyadmin on December 21, 2020

The chances that you may have inherited an old alarm system with the purchase of your house in South Africa is relatively good. In my case the alarm system was quite an arcade unit and its only purpose was essentially to arm it when we not at home or go to sleep and have the security company on call should any of the areas are breached while in an armed state or a panic signal triggered.

Other than that I personally found the alarm system to be an eyesore with all the PIR sensors and door magnets all over the house and the glued cables to power and connect to the alarm distribution box which in itself looks like a crows nest. But we live in South Africa and the reality is that the system serves a purpose at the end of the day as far as security and emergencies go. 

As the saying goes… If you cant beat them join them. And that was the mindset I had with my home alarm system. There just had to be more that could be done with it than simply arming and disarming when needed!

On the other hand I had a Home Assistant platform which could control lights, switches, monitor power and perform automations which was expanding at a fierce rate, and then the penny dropped…

Why cant I use the existing alarm and integrate it with Home Assistant so that it actually serve a purpose as far as presence detection go with  the PIR sensors or automations when doors or windows get open or closed.


Before we jump into the good stuff I would just like to state that this integration is not a replacement for your existing alarm system. The purpose of the project for myself was to run it in parallel with the existing alarm so that i had the to created some automations or control its arming and disarming via Home Assistant. It is also important to note that the system only works on wired magnet sensors and PIR sensors. Unfortunately wireless beans and PIR sensors wont work.

Each module built supports 6 wired zones on the alarm so if you have more zones to be considered you would have to double up on modules to accommodate the amount of zones. Arming and Disarming the alarm will also require a dedicated zone for programming as a keyswitch.  

What you will need for the project:

  • NodeMCU(WiFi)
  • Relay Module(Switch)
  • Female to female Jumper Wires
  • Male to female jumper wires

Tools you may require

  • Small flat head screw driver
  • Small Philips screw driver
  • Wire strippers
  • Advisable to have a multi tester

Preparation Steps

1.) Alarm Integration Module Assembly
2.) Test and Document all Existing sensors
2.) Prepare Hardware with firmware
3.) Installation of Hardware
4.) Wire connectivity to alarm panel
5.) Powering the System

Module Build 

The electronics for the build are relatively easy to obtain. I will leave some links in the Additional Resources section of this post should you wish to purchase online. Otherwise you can check out our website and I will be happy to preassemble and flash for you and place it in a 3D printed enclosure.

There are 3 main components to the assembly of the integration module:

  • NodeMCU
  • Relay Module 
  • Buck Converter 


The NodeMCU is essentially a WiFi module with programmable pins called GPIOs. There are 6 available pins which can be connected to the alarm panel for monitoring state changes to the relevant zones and also the reason that you will need to build a second integration module should there be more wired zones to cover. 

Something else to bear in mind is that the ability to arm and disarm your alarm is done through one of the available GPIO pins mentioned. So in a situation where you would like to arm and disarm the alarm with a single integration module you will have 5 pins available to assign to zones(PIR sensors, door and window magnets) and the 6th pin will be assigned to the relay for controlling the arm and disarm of the alarm.

The GPIO Pins available are as follows:

D1, D2, D5, D6, D7 and RX

Each pin will be wired to a Zone on your alarm panel. For example Pin D1 on the NodeMCU will be connected to Zone 1 on your Alarm Panel, D2 to Zone 2 and so forth. You will also need to make use of Ground on the NodeMCU as this is connected to the alarm panel COM ports.

Relay Module 

The relay module acts as a switch which is controlled by the NodeMCU through electrical signal. It 
momentarily opens or close the circuit which in turn creates the action on the alarm panel to arm/disarm. 
As an example if Zone 6 on the alarm panel is programmed as a keyswitch to arm and disarm the alarm. The circuit across Z6 and COM is closed with the appropriate resistor for the panel via the NC/COM contacts on the relay. When signaled by the NodeMCU, the relay momentarily opens this connection, triggering the traditional panel to arm or disarm.

Buck Converter 

The buck converter is used to power the NodeMCU directly from the alarm panel using its auxiliary power. The alarm panel runs on 12v and the converter is used to step the voltage down to 5v as this is the operating voltage for the NodeMCU.
Once the unit has been assembled and tested to ensure it is turning on ok you can start looking at the existing wiring of the alarm to prepare for the connectivity to the zones.

Document wired sensors

Go to each door & window, testing every sensor. You can use a multimeter if you have one & know how to operate it. Alternatively watching the sensor status change on your alarm key panel would give a good indication of what wired sensor controls which in your unique configuration.

Make a spreadsheet of all sensors in the house and label / relabel each sensor wire prior to moving on to the integration.

To note

  • Open/closed sensor wires are typically a pair of wires: one red & one black. A security system can tell when a sensor is “broken” (ie: a door/window is open) because the circuit is broken.
  • Some sensors require power, like motion detectors. These are usually four wires: two for power & two for the sensor signal.
  • Keypads usually have four wires. Two for power & two for data.
Prepare Hardware with firmware

  • Download the firmware from 
  • Flash the device with the latest firmware and filesystem firmware/releases 
  • Download the Konnected Flash Tool for your operating system.

  Flash Tool for Windows (64 bit)

  Flash Tool for Windows (32 bit)

  Konnected Flash Tool for Mac

  • Download the firmware  .bin file and filesystem .img file from 
  • Disconnect the power first, then remove the NodeMCU WiFi module from the wiring base. Plug the WiFi module to your computer using a data quality micro-USB cable.
  • Launch the Flash Tool that you downloaded in previous step and select the device port from the USB Serial port drop-down list.
  • Browse to Firmware image and Filesystem image and locate the files in the firmware directory that you downloaded. The files should be clearly labelled firmware and filesystem.
  • Click Flash Now to begin flashing. The process only takes about a minute and you can watch the progress in the Console output.
  • Once you see Done. printed in the console output, it’s safe to unplug the WiFi module. 
  • Connect to the WiFi network which should appear on you computer available wireless connection and should resemble konnected-security_XXXXXX to set up WiFi

  1.     Disconnect the power and backup battery from the traditional wired alarm system before you begin.
  2.     Mount the Interface module near the wired zones of the traditional alarm panel, and connect using the provided connector     cables Alarm Panel. Each 6-zone Interface module requires a connection to the Alarm Panel board.
  3.     Identify the AUX output (usually 12VDC) on the traditional alarm panel. Connect GND and + on the Interface module to AUX-     and AUX+ on the traditional panel, respectively. This is necessary to provide an operating voltage reference to the device.
  4.     Connect the zone inputs 1 – 6 on the Interface module to the wired zones on the traditional panel. Be careful to leave the     existing wires intact!
  5.     Power back on the traditional panel, reconnect the backup battery, and ensure the Integration module is powered. The power light should illuminate on the Integration Module.