Suggestions for placement of ST Multipurpose Sensor on door

Need some suggestions on good placement for this ST Multipurpose sensor on my door. I’ve attached photos. As you can see I’ll have to attach one piece on moulding that isn’t even and obviously a piece on the door. Any advice on which piece would be better suited to which side? As you can see from the photo I don’t have the space to install the smaller piece inside the area between the moulding and the door. And what is the max distance each piece can be away from one another?
Thanks in advance!


The smaller piece is literally just a magnet in a fancy case. When it’s close enough to the other piece, it pulls a tiny metal needle, called a “reed,” Inside the other piece into position where it closes a circuit. So then the sensor registers as closed.

What all of that means is that if you want, you can substitute any other magnet, including one that is much stronger or much weaker. The stronger the magnet, the greater the distance you could have between the two pieces. So sometimes people solve this kind of problem by replacing the small piece with a stronger magnet. :sunglasses:

As far as which piece goes where, I personally prefer to put the bigger piece where it won’t move, because it’s the piece that has actual equipment in it. And if the door gets slammed or people bump into it, eventually vibration might cause some problems.

On the other hand, if you want the sensor to detect vibration, then you have to put the bigger piece on the area where the vibration will occur.

So different things will work for different people.

I have to say, looking at your pictures, I personally would use a Sensative Strip instead. This is a very thin Z wave sensor that fits inside the door frame and can be painted as well so it will be almost invisible. These work very well with smartthings, no one will bump into them, the only real issue is that they’re more expensive.

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I had a similar problem. I put the big piece on the door and used a chisel to create a small notch for the magnet in the trim. You can barely see it.

I bought some flat magnets from Amazon (they’re pretty cheap). They take the place of the smaller end and work perfectly (in my case they’re on PVC doors).

Sorry for being blunt but this is where I recommend placing ST branded sensors…


Id recommend a zwave plus sensor or Iris sensor.


If you want to have constant issues and a generally unreliable sensor then I would continue to find a place to put it. However, you would be much better off with this one or an Iris contact. They both run locally and are pretty reliable.

David, would you recommend the iris motion sensor over the ST motion sensor as well? I currently have one running in the bedroom to turn the lights on when you walk in the room… Has worked good so far, however I do notice you’ve taken a good 3-5 steps into the room before the lights trigger.

Hmmmm… I might try this out. Obviously this won’t interfere with my actual garage door opener will it? I personally haven’t had issues with my ST devices. Which is why I have continued to purchase little at a time more ST devices. Thanks for advice… I’m gonna try this suggestion.

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Lol. I totally through my blurred vision saw a garage door in your initial post.

I removed the entire post instead of editing it everywhere.

I’m using it on my garage door with the MyQ Lite SmartApp.

But what I said in the other post before I deleted it in already having the device and making sure it works for you and if not, then look at some of the other recommended solutions that work for others.

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Haha… Gotcha
No worries. I’ll try some of the other suggestions then. Appreciate ya.

The iris sensor is typically one of the quickest to respond, so I would look into two possibilities.

First, the placement of the sensor itself. See the following FAQ:

Second, if sensor placement doesn’t solve it, then consider the “strength of your mesh,” which means how many mains powered devices you have and their placement to help pass the signal along to your hub. Battery powered devices cannot help in this regard.

See the following thread. Start with post 11, then go back up to the top of that thread and read the whole thing. (This is a clickable link)

I’m also using an ST Multisensor in my doorbell box. The sensor is shoved inside the box above the ding plate with the magnet on top of the box (keeps it always in Closed state). Then when someone rings the doorbell and the spring hits the plate, the acceleration in the sensor is triggered and via Big Talker and webCoRE I get an audio notification announcing that someone is at the door that someone is at the door instead of s dong dong. This also allows me to know that someone is at the door when I’m not home, and I can bird them on my Nest camers. Lotsa uses for them and they have been 100% reliable for me.

Yes I would recommend the iris motion sensor, I use them exclusively. I find them to have the quickest response so try what JD said eairler :point_up:

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JD … These were a great source of information. Thank you very much for your assistance. You’ve been a great help answering questions for me on my Home Automation journey!

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The big piece should actually be on the door and the small piece in the door frame.

The big piece contains vibration sensors to help you know if someone is pounding on your door or kicking it.

Different things work for different people. :sunglasses: Some people will want the vibration sensor on the door, others will not. It’s usefulness as an intruder alert will vary by the specific set up as well.