As of yesterday morning my Smartthings motion sensor appears to have died. Tried replacing the battery etc… but im not even getting the led to flash so im presuming its just given up.
With that im on the lookout for a new cheap one. Ideally with the same features and the same sleek dimensions because it needs to sit on a 2cm ledge.
Any contenders out there in the UK or is the best to get a straight replacement?
Look at the Xaiomi Motion sensors. They’re about a tenner on eBay. For that price I can’t fault them and they’re tiny as well. Good DTH on here as well. Note that it does not measure temp.
If you’re interested you might want to look for someone outside of China selling them for quicker delivery.
http://xiaomi-mi.com/smart-home/xiaomi-mi-smart-home-kit/
edit: Bit more but shipped from Salford:
http://www.ebay.co.uk/itm/Original-Xiaomi-Intelligent-Human-Sensor-Control-Smart-Home-Suit-Kit-Accessory-/381783488086?hash=item58e411b656:g:kWUAAOSwNRdX5ERE
DTH:
Good shout. The price point is ideal - what are the response times like with it? How does it perform in a dark hallway?
The only issue i can is its dimensions. My current one sits on a flat lip of a door frame, hence the 2cm request. So if i was to get this one id have to play about with placement somewhat.
EDIT: Actually… after seeing a video of it - I didn’t understand how small it actually is. Yes there might be a bit of overhang - but some velcro will probably fix that.
One of my sensors died, I went cheap and tried a non branded battery, absolutely nothing.
Bought a Duracell and it fired up first time.
Hadn’t realised that these things only work with certain brands of battery - apparently even a minor size variation is enough to affect the connection.
Something about Samsung and batteries. 
My replacement is an Energizer one so I think it should be fine. The fact that I’m not even getting a blue LED is the worrying part. It’s just showing no signs of life at all.
I had that happen to one of mine 2 months ago.
Raised a support ticket and worked with the support staff.
They confirmed it was dead and as it was under warranty they replaced it.
The problem is I’m getting the ST ones drop off the network on a regular basis.
My Hue, Orvibo and Fibaro ones keep working faultlessly.
EDIT: As I had 2 ST motion sensors I was able to swap batteries between the 2 sensors to prove it was faulty. The good one worked with the new battery and the one it had in it originally. Fault has to be with sensor.
I’ll ask - “shy bairns get nowt” as they say in my neck of the woods!
Someone else on the forum tried Energiser batters with no luck.
Might be worth having a look at the post.
It’s not the quality of the battery, it is the shape of it. Hard to describe but the side on contact of the motion sensor is very low. Seems only Panasonic and duracells can easily touch the contact. As their side walls are deeper.
The one previously was an Energiser and that didn’t seem to have much of an issue - but I take your point. The whole thing is just ridiculous really!
Might pop to the shops and see if I can find some Panasonic / Duracells 2450 ones.
Couple of photos of the two sensors side by side in case anyone interested in dimensions. Xiaomi also comes with double sided pad on the base.
Wow. They are small. Might get one to go with my other 4 makes!!! 
Yeah. I saw that. I was going to order 2.
Bargain.
I got mine from banggood.com they are not the fastest but they’re cheap. Door sensors are tiny too! Even compared to the Orvibo’s
I had the same thing and same problem with the batteries and thought two of my sensors were dead. However, only duracel batteries worked for me, one thing I did do to prove this was connect some wires temporarily with tape and touch the connections. When I did this the led came on but would only work with a duracel fitted in the unit.
Likewise but I thought £3.99 delivery was too expensive.
Well…!!!
What do you know? Ordered a couple of Duracell 2450’s on Amazon Prime - fitted them - boom…on comes the LED. Unreal.
I don’t know whether to laugh or cry. Surely this design flaw should fall at Samsung’s feet rather than every other battery maker?!
Energizer CR2450 batteries DO NOT WORK!
There’s too much of a step on the side, on Duracell the side of the battery goes down almost to the base (when +ve is upwards), on Energizer it stops 1mm short and doesn’t make contact with the prongs.
I tried to bend the prongs up and snapped them off - whoops - but bodged it back together with the spring from a ballpoint pen screwed down over the remenants of the prong.
This means that the spring sticking up now contacts the side of my Energizer battery
I have found the SmartThings sensors to be quite bad quality - the multi is OK but my Presence sensor battery compartment has broken (because you need to swap the batteries so often, and the little hooks are such thin plastic - appreciate this is a “brought in” part though) and my Motion sensor just pulls apart, so when you’re trying to change the battery actually the white front grips the middle piece, better than the middle piece grabs the rear. This means instead of the two grey bits staying together and the battery change being a doddle, the circuit falls out, the reset button bounces across the floor, and it all needs carefully clipping back together.
See first post here:
