Alarm System Logic

Hello everyone,
My first post and really excited to be using Homey. Ive just migrated from smartthings which has in my opinion really not kept up with the smarthome tech offered elsewhere!

I am mostly setup but considering a few extra purchases around home security and wanted to see if Homey could replicate something i had setup previously using a smartthings app.

Its a DIY alarm system, using sonos, motion sensors and door/ window sensors. The idea is simple… (i think)

If motion is triggered outside the property and a door is opened then trigger the alarms… unless, motion is detected inside the house first.

Idea being is, its 2am and I let the dog out, it will know I walked out of my bedroom.

Any thoughts, concerns or ideas? Only thing i can think of is the delay on a motion sensor?

Hope I can contribute something back to this community, its full of great reading!


1 Like

Hi FranklyEpic,

Are you on the bridge or Pro?

If Pro: Do you know the Heimdall app? Heimdall - Let Homey watch over your home

Good morning,
I am using pro.

Yes I will use Heimdall for this. I think my question was more geared towards the logic of the sensors. Almost like IFTTT type logic with and / but to ensure it only triggers when its not us.

Thank you.

Ah sorry, didn’t understand that. It is difficult to use motion/door sensors to know when the alarm has to be activated. If you sit still for a long time it will also trigger to turn the alarm on.

Why not use presence / location based triggers?
IF last person leaves home
THEN activate the alarm

IF Someone is coming home
THEN deactivate the alarm

In the Heimdall app you can choose on which sensors triggers the alarm. And also set an interval when the alarm has to go on.

I use it this way. When the last person is leaving home further than 50 meters the alarm is activated based on location. When there is activity in the house on any (door/window/motion) sensor the alarm flow will run with sound/lights. The alarm will be deactivated when I get home.

  • Or you could also work with Beacons to activate the alarm when you leave the house.

  • Or make a separate (virtual) button

IF Button click
AND Alarm is deactivated
THEN Activate alarm

When you come home:
IF Button click
AND Alarm is activated
THEN Deactivate alarm

Thanks for the feedback… thats actually really useful.

Sorry but can i pick your brains again qnout the sensors? The example you have shown above is perfect for us leaving the house but what i am looking for is a flow gor when we are in the house (at night time).

The only reason to use the sensor, is to tell the alarm not to activate if we are up and about. The dog example is actually the problem. I need the alarm to not trigger if i open the back door at 2am to let dogo out.

By using an inside motion sensor, it will validate we are moving around and thus, if anything happens, it will be me/us not an intruder.

You could reverse the logic? If motion detected outside (on camera) and door sensor opens, reign hell… if motion detected inside and door sensor opens (do nothing)…

As you said, after a period of time (10 minutes) reactivate alarm.

Please tell me if i am overcomplicated this issue.

Thabks again

I would choose 1 dedicated motion sensor(A) around your bedroom for the dog example.
make a flow:

IF motion on sensor A
AND surveilance mode is active
THEN deactivate surveilance mode and reactivate with delay of 10 min.

now incluide all other sensors (except this dedicated one above) in heimdal to guard the house when surveilance mode is active.

or you could also make use of alarm delay in the heimdal app settings and make use of this flow and include all sensors:
IF “The alarm delay is activated.”
AND motion in particular room(bedroom maybe or hallway?)
THEN deactivate surveillance mode

1 other option I use right now but involves a smart device purchase is the withings sleep tracking pads to know when someone is in or out of his/her bed and according to that you can switch your surveillance mode.

1 Like

You can create a virtual motion sensor.
Have the actual motionsensor trigger the virtual motion sensor.

For the virtual motionsensor you can fully control yourself how long this sensor will report “activity”

Now use the virtual motion sensor to control if your alam will be triggered (many ways to do that)

  • use it in the AND
  • use it to disable the alarm flows

Really sorry for the delay, have been unwell!
This has worked perfectly and I am going to add the virtual sensor as you said, when I am feeling brave enough… otherwise, for now it works!

Thank you all very much!

1 Like