Thank you for the info.
Since it is only $30 I will try one and see what happens ...
But if it will create a problem it simply will go into "spare toys" drawer.
Ali has been good about compensating me. At first the seller will offer you 5 cents, then you can complain to Ali, of course with videos/pics and they help me out 95% of the time with full refunds. And there is always a CC chargeback or paypal (paypal is getting much worse with seller protection). Paypal used to reimburse return shipping, but they're stopping that or already have.
AliExpress didn't seem interested in helping, and the seller ("Mijia-Global Store") didn't respond to my messages. I finally put a dispute in with Paypal. Only after that did the seller started responding to my messages (and AliExpress stopped). But they just strung me along until Paypal finally said the "the item wasn't lost in shipping" -- and why Paypal said that I don't know, since I said the item didn't work. I reopened the Paypal dispute and finally they offered me a $50 credit (WHY? that isn't getting the seller to back up what they sell).
Anyway, Paypal's guarantees are effectively worthless and I won't use them again for any real transaction - there's no way to get a human involved. AliExpress didn't care. And the random sellers on AliExpress with names that sound like real companies are just random folks in China.
I have one of those ones the OP asked about.... it was the first MMR I got.
Its not nearly as good as the later ones I bought.... it works for some applications but looks ugly and is HUGE! And you can't adjust the parameters on it (clear time, range etc)... also short range - maybe 10 feet max.
There is an excellent thread on here about MMR devices.
@vitaliy_kh I am curious, how was your experience? Looking for something easy to install in the bathroom, currently, I have a mess with 2 motion sensors and I am looking for an alternative.
The other devices look like you need to connect to the electricity in the ceiling. Not like this one.
What do you think for a small room?
Unfortunately I did not do my homework upfront.
According to device driver creator (@kkossev) this specific unit is very chatty and therefore
not recommended. So, I did not bother even to unpack it and it immediately went into
"just in case" box.