Magnetic window contact sensor

[Koen Colen]

Hi,

First post here.

I have a loxone system and I have digital inputs at every window location in the house. This via a DI module, over the tree bus.

Now it's time to install new windows in my renovation.

What (hidden) window sensors do you guys recommend? Is there a standard used in the loxone community?

And where to buy them?

I found next page but it's not fully clear to me what the differences between each item are. For example when to buy a contact with and when to buy one without a resistor?

https://www.dhzbeveiliging.nl/index.php?item=magneetcontacten&action=page&group_id=13&lang=nl#.WnHgOpM-eAz

All info, including webshops very welcome.

Thanks a lot!

Koen Coen

[Liteworx AV]

If you have standard digital inputs at each window you would not need the sensors with the resistor built in, the resistors are used for standard types of intruder alarms to save running individual cable pairs for alarm and tamper circuits (a different resistance is placed over a single pair which the alarm panel can differentiate between an alarm and a tamper condition based on the resistance) the vast majority of door and window contacts work with a simple normally closed reed switch (contacts close when door / window shut)

You can pick up standard recessed sensors (reed switchs) for a lot less cost than 8.53 euro as in your link, her in the UK you can pick them up for under £1 GBP

https://www.maplin.co.uk/p/recessed-magnetic-contactreed-switch-yw46a

[Koen Colen]

Thanks Liteworx! That was exactly the info I was looking for.

I am about to order wooden framed windows, I seem to like the metal sensors with the screw thread on them. They look more durable to me than the plastic ones.

Does contact distance matter? Bigger is better?

Thanks again!

[Liteworx AV]

I've found that most sensors work up until they are around 10 to 20mm apart, I don't think there's a huge difference in effectiveness in relation to size  

as long as the two parts (magnet and switch) are as close as possible when the window is closed you should be ok.

To be sure which ever sensors you buy, connect them to a multi meter and check the distance required for them to operate 

[BartVB]

With most vendors it's possible to order window frames with the contacts installed. That makes for a much cleaner appearance. By default factory-installed sensors cost you an arm and a leg but it's a nice point for negotiation :)

[Rob_in]

Sadly not :(

In fact, when I asked about fitting sensors the supplier for our windows said if we drill holes in the frames, etc. for sensors it would invalidate the warranty.

Because of that, and that we have doors where two leafs slide (put one sensor/contact pair in the centre to detect movement in either side) I'm considering some wireless sensors (yerch!). Yes, but needs must. Has anyone any experience with these? Something like this for example:

https://www.aliexpress.com/item/Kerui-Wireless-Doorwin-dow-Gap-Sensor-For-KERUI-GSM-PSTN-Alarm-System-Alarm-Accessory-433MHz/32577604635.html

I'd probably have to build a 433Mhz receiver with an Arduino or something. Not an urgent project ;)

Robin

[RSinn]

There's lots on AliExpress for around £0.70 each.

Circular ones that you can embed in the frame so are hidden are good but some doors have lots of metal/mechanism on the edge so had to opt for the rectangular surface mount type.

The problem I found was the magnet was too weak to get a good reliable switch so consider upgrading the magnets (eBay). The other thing is getting the sweet spot, I wanted it to highlight a window open even a tiny bit. That's still an open window but if you put it in anyhow it won't trigger until the window is 20mm open. You could think all your windows are closed and go on holiday and things are still open

[Simon Still]

On Monday, 5 February 2018 23:22:54 UTC, Liteworx AV wrote:

I've found that most sensors work up until they are around 10 to 20mm apart, I don't think there's a huge difference in effectiveness in relation to size  

as long as the two parts (magnet and switch) are as close as possible when the window is closed you should be ok.

Hmm.  That wasn't my experience.  

I fitted this type - https://www.tlc-direct.co.uk/Products/TS011.html? to my front door.  

My door has extruded aluminium sections with plastic inserts on the faces that meet so I had to cut a hole in the plastic cover and drill a hole in the frame behind.  

I found - 

- it's actually surprisingly difficult to ensure the two halves are perfectly lined up. I think i probably got it a few mm off (but pretty much impossible to be sure).  

- I'd be very surprised if the gap is more than 5mm but it's pretty unreliable.  Interesting idea about a stronger magnet - that might be a solution. 

I was using it to switch on the hall lights (after dark) and turn the house back to 'at home' mode when I got home.  Since we'd got an i-button controlled outer gate I now do it using that.