Try pushing the little button several times while pairing is in progress. Keeps the device awake. I have 10 Mygbett sensors connected like this… Works like a charm!
So i got mine to add to my Homey quitey easily. But the motion sensor is just saying it is detecting all the time (little flashing Red Man). I have even covered it over to stop any kind of movement. Any ideas what am i missing here?
This most probably is caused by the fact some Ikea sensors seem to need rechargeable batteries instead of regulars.
Difference:
Rechargeable: 1.2VDC
Regular: 1.5VDC
So 1.2VDC seems to be the very max power to supply.
The stuff is so damn cheap, Ikea didn’t bother to throw in a voltage regulator (in other words they say: NOT OUR PROBLEM)
I had problems with my MYGGBETT as well until I kept my phone, Homey and MYGGBETT really close (<50cm) together while pairing.
I’m using ordinary Maxell / GP batteries in both VALLHORN and MYGGBETT sensors.
For me adding the devices was near to impossible via Homey directly but it worked immediately when I used the option to add the device via Android.
Tested it now with 5 devices. All same behavior.
One other thing is that updating the firmware for these devices may fail easily 3-5 times before it actually does the update. Doesn’t really matter if the device is very close to Homey or not
so is the problem Homey or Okea… It is very frustrating. Managed 4 sensors in 3 days…
Yes, adding MYGGBETT and GRILLPLATS was a real PIA… 
I don’t remember how many times I tried before I succeeded.
I gave up on two KAJPLATS GU10’s and put those in Zigbee mode for now. I might try again “later” (if ever 
). Those connected just fine with Matter but went offline after random time (5min to few hrs) but they work flawlessly in Zigbee mode.
FW updates is also a painful experiment. On identical devices it can 2 retries or 15 if You are unlucky. And never a clue why it failed, so there is some room for improvement. Hopefully the Zigbee-part of FW update works somewhat better…
Ok. So once you have them pairs, has anyone got a magic trick to update them… They are truely frustrationibg piece of equipment
I have no idea how my MYGGSPRAY got updated…
I tried several times w/o success.
Then I read something about battery consumption during update so I replaced batteries but it still failed.
So I left the device quite close to my Homey overnight and guess if I was surprised next day when I realized that FW was updated “automagically”…
So, I worked out my thread network was the issue. I have an Eero home network with Thread turned on, A aqara M200 with thread, Homey Pro and Google Streamers around the house. All working against each other. The main issue was Google streamers. So turned off everything not needed. Then deleted and reinstall 15 Myggspray sensor’s AND upgraded them to v1.1.4. Which is apparently the fix for Thread reliability. All in 3 hours…
So the next thing is to try and resolve the Thread network and understand how it actually works correctly.. Seems that even though it is not new, it is a little hard to work with, not really clear what to do and not to do… You would think that the technology would recognise and existing thread network is establlished and either just join or give you the option when you configure it…
Today I added a Myggspray. Here’s how I did it.
Using the Homey app on my iPhone, I went to “Add Device,” selected “IKEA,” then “Myggspray,” and entered the Matter code. A new Myggspray is always already in pairing mode. On my first and second attempts, I stopped after about 5 minutes because it took forever to find the device.
On the third try, I placed the Myggspray about 50 cm away from the Homey Pro and just waited. After about 15! minutes, it was connected… 
Motion detection has actually been working very well so far.
And keep pushing the connect button every 5 seconds during pairing. It works within a minute…
