Unboxing video posted a day ago
Looked at this again today, the time to pre-order hasn’t gone down. Only the seconds element of the time is changing 
Looks like they have sorted out the countdown timer now, says preorders begin in 5 and an half hours. So we’ll know the price and maybe the lead time tomorrow
Sold out 1st batch July shipping
Most presence sensors use a low power communication to a zwave or zigbee. I have one that’s in the kitchen and it’s going on 2years. So battery use is very modest.
And now it’s available for pre-order … except it’s not. Although we now know the preorder and full price. It says it’s sold out, but I don’t think it was actually available as I checked not long after the countdown timer passed.
I checked shortly after the countdown finished. It was sold out already. Either they had a tiny volume of preorders or they haven’t actually taken any preorders yet
A presence sensor or a motion sensor?
There are lots of zwave or Zigbee motion sensors available that typically have a 1 to 2 year battery life. Those work by “sampling“ the environment, typically every three minutes, looking for a change in heat on a PIR sensor, passing across the lens.
Those are good for detecting something new entering the room, but they typically won’t report that someone sleeping in a bed or even just sitting in a chair is still there the next time they do the sample.
So an alternative that has become popular in the last two years is a “human presence sensor“ using MM wave technology. Those are something like radar. But the point is they can detect even “very fine“ movements like a person breathing. And can do so pretty much continuously.
So they have no trouble telling that there is someone sleeping in the bed. Or sitting in the chair. But in order to do that, they collect huge amounts of data on a nearly continuous basis, and that’s what uses up all the battery life. So so far Almost all of these have been Main’s powered.
It was available. I placed an order approx 90 min after release. Not sure if there were different volumes available or demands between US and EU.
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Ah, I obviously want quick enough then and they either had a massive rush for orders or a v small volume available on pre-order
4 posts were split to a new topic: mmWave sensor built into a light switch?
Ordered one from second batch, only 3 months to wait 
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Did you receive this yet? If so, any feedback on how it performs?
I did receive them. I wasn’t able to connect to smartthings on the first attempt and I’ve been slammed. I haven’t had anytime to mess around with it. But kids go back to school in a few weeks, so I’ll be able to resume my “nerd stuff” as they call it.
Have you received yours?
Nope, mine was the second batch so not due till September
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Not an Aqara forum member so I’m ineligible, but interested to see how this pans out. I think i prefer the shape of the Aqara device but it will be down to performance and battery life that’s more important. I’ll be glad to get shot of my sonoff presence sensor as it’s just not reliable at all for me, despite extended trials and swapping driver multiple times.
Selling 3rd batch now, price increased from £25 to £37 ($50), very cheeky if you ask me!
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Showing $39.90 for me.
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