UK - dry input contact sensor?


I’m looking for a zwave or zigbee low cost contact sensor (or similar) battery operated device that I could wire a pressure mat up to. Lots of US Zwave contact sensors with dry inputs but can find anything for purchase in the UK.

Any clues?

Thanks in advance!


Fibaro UBS but it's 9-30v power need

I've just bought a batch of 20 Iris window/door sensors from US off Ebay

Worked out to be under £4 each after postage and import taxes, already used a few for doors but the aim for the others is to create room presence sensors with pressure mats.

At £4 each it's a no brainer, even if I knacker a few adding them to pressure mats it's still cheaper than buying local

Interesting. How do you plan to convert them?

I watched a video on YouTube where they soldered the wires from a pressure mat go the circuit board in a sensor then added a cut out to sensor case for the wire, thought I'd give it a try.

Forgot to add the sensors are v1 iris type

Would a leak sensor do the trick?
Found these on Amazon

I have one here which works very well, but could be used for your project?

I have found that leak sensors are not designed to run on "contact closed" state for a long period of time. I think that they pass quite a high current to be able to close the contact using water and consequently run their battery flat very quicky when faced with a wired contact shorting out the leak detection.

Modifying door open / closed contacts is a better way of doing it.

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Understand that, but for the purposes of a presure mat? Wouldnt it effectively be the same.

No pressure = dry
Pressure applied = wet

Kind of thing. Unless something is on the mat for a very long time, then of course that would drain them quicker. And if needed, you could hack it further to be run by USB power.

Failing that, it looks like the Xiaomi sensors could be played with, according to this post I saw.

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You have a point for a pressure mat as you shouldn't be standing on it for very long. I used a modified water sensor on the relay controlling the "low temperature" lamp on my freezer and it only lasted 2 days before the battery ran flat. I found that using a modified door sensor was more reliable. for the pressure mat you could also use a modified push-button as this is effectively what the mat is, a very large push button.

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In fact, this one is probably better, this guy hacked the Xiaomi contact sensor in a simlilar manner for a door lock sesnor, but the theory would be similar.

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My use case is to stick our wheelie bin on top of it and for it to notify us if the wheelie bin was still there on bin day that we hadn’t put it out for collection... not something I want to spend a huge sum on obviously :slight_smile: However, it was my girlfriends suggestion and she’s not in to HA in any sort of way so could be the start of a positive sign :slight_smile:

I ordered the water sensor as it was so cheap.. without reading the other posts but sounds like that could drain the battery quickly in my case... I wander if there is a way to “reverse” the operation of it ..

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If Amazon, then you can cancel today too :+1:

But as they have handles, any way you can stick a contact to something at the back of it? Presuming the bin backs onto something, or at floor level? Just need to find a sure way that the magnet wouldn't come off whilst being emptied, but at the end of the day it is just a magnet :slight_smile:

He's also selling the contacts too.

Not sure why that shows at £21.91, I see £10 + £6 delivery.

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I thought about the magnet but they throw the bins around and I think I’d be forever replacing magnets.

I’ve got a few old contact sensors lying around so I’m going to experiment with these, Soldiering iron ordered ... what could possibly go wrong :roll_eyes:

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With today's bin men? :joy: Almost anything!

But you have got me thinking about this.
Ours are bi-weekly, black bin one week, recycling bins the next, and I always forget which is day it is (black or Blue/Green). Then I have to go out front and see what the neighbours are doing lol.

So first step is trying to figure out a rule (piston in my case) which can tell me which day it is.
Once I can get that working, I'd like to do something along your lines, although we have 4, and as above I don't want to be replacing magnets all the time, although duct tape may be the cure there :wink:


Keep in mind any magnets work, you just need a strong one. I have these on my fridge to hold up kids papers and used one on my mailbox for a contact sensor to notify me that mail has arrived (I live in US). They are pretty flat and can be glued or taped to your bins. I don’t have experience with these exact ones and picked the first hit I could find on amazon. There are multiple choices for “rare earth magnets”.


It works !


According to the Pushover notification, you forgot. Perhaps a dog shock collar might be a better reminder. :wink:


Think I could rig a contact sensor to one to automate that ? I’ll start a new thread ! :rofl:


I’m looking at doing the same but for a different application.
A bed presence sensor.

We have memory foam ‘toppers’ on all our beds and I’m hoping that one or more pressure mats between the matress and the topper would show me when someone is in bed.

If it works well then I can automate lights etc based off this :slight_smile:

I have used quite a few contact sensors as an ‘indicator’
I even adapted a driver to convert ‘open’ to off and ‘closed’ to on and added the switch capability so it’s easier to use in apps etc.

Works for me


I bought the Withings sleep sensor. It's awesome, although via IFTTT since no direct integration. The app is great too, Tracks sleep and provides useful stats. It goes under the mattress but is sensitive enough to pick up breathing, snoring etc. Very cool. Wouldn't use it as a bin sensor tho' lol

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