Burglar alarm / Rfid activation / Lcd screen / Motion detection / Delays ...


I made this burglar alarm using an Arduino Uno, RFID proximity reader, LCD display and LCD serial backpack as its main components.
It features entry- and exit delays and is triggered by magnetic switches, motion detectors or tamper switches (inside the control panels, motion detectors and unit).

Check the movie at the bottom

Notes on the build:

You can use whatever you want to set or disarm the alarm with the code provided, it doesn’t have to be Rfid controlled.
At first I used a simple keyswitch.

As my control panels are about 10m away from the arduino you can’t hook up the LCD’s the “standard” way using 6 wires.
You get gibberish on the screens.
To overcome this problem you have to use serial communication. The easiest way to do this is by adding a serial backpack to the LCD displays. You can buy these at www.sparkfun.com (see schematic) . As a bonus you only need 3 wires to run the display.

The RFID part of the project can of course be done using an Arduino but sometimes you have to go for the cheap, easy and fast way.
These proximity readers you can buy at www.velleman.com (see schematic) as a kit (about 28 €) or assembled (about 40€).
I bought the kit and soldered it together in about half an hour. Clear instructions, peace of cake…
(you can find rfid readers at sparkfun as well, maybe easier buying everything at once from the same dealer…)

Tamper switches are included. When the alarm is not set it shows an indication that wiring should be checked.
If the alarm is set and there is tampering, the siren kicks in and resetting by means of the control panel is denied completely.

The front of the control panel is a rectangular piece of glass (4mm thick) that I sprayed black on the back (except the window for the display). When dry, hold it in place with some strong tape that sticks on both sides, and put a thin line of transparent silicone around. It holds very well (you need a knife to cut the seal) and looks neat and clean.

I have included a little movie, a wiring schematic and the code with so much comment in it, it should be clear to anyone.

Hope you enjoy…

alarm movie (small).mp4 (1.64 MB)

alarm wiring.dwg (53.6 KB)

alarm code.txt (38.1 KB)

Hi Tom!

Nice project!!! Could you please tell me what kind of PIR sensor did you use? I'm playing at the moment with a simple model: http://www.vetco.net/catalog/images/VUPN5943-1.jpg

The problem wih the model I have is that it's not very sensitive at all.


Hi hs2o4,

I see you experiment with the same kind I used (small build-in type) with the same result...sometimes unpredictable...
Thinking of changing to the normal style, the one I'm thinking of (EtiamPro HAA52N: PIR INTRUSION DETECTOR – Velleman – Wholesaler and developer of electronics)

Regards Tom

Hello Tom, When you update your project by adding the GSM module can also update this post?
I am interested in your project and I'm studying.
Many congratulations on your work.
Hello See you soon

Hi Tom DK,

my congrats, A very well documented and achived project.
Great work. I may use that as a base for my alarm system
as you have thought about all features I was thinking and beyont.

Would be great to know your experience with the stability of the system or if you
face some issues (e.g. time rolover after 52 days).

Apreciate for the files.


Good project!

Im working on one alarm project too, but without rfid (Alarm Update - YouTube).


I need to make an ALARM system that is controlled by sending an SMS. These are the components that I have.



  • When motion is detected, the buzzer needs to sound (ALARM activated/SET) and send user and SMS notification.
  • Send SMS to de-activate the ALARM and send a notification to user that ALARM is armed.
  • Send SMS to get STATUS of ALARM.

I will start working on the code this weekend and see how far I can go.

Please give me advise on how to achieve this goal.