I was thinking like this article. The shape looked like a typical PIR sensor.
And there is no reason to use two sensors.
You actually have it. What is your opinion?
If what is applied to this sensor is not "mmWave", it will be settled in dispute. target.
Behaves strange, as I already mentioned... I want to first finish the driver for it as I have already spent time, then will crack open it to see what is inside. I may end up satisfying my curiosity at a high price ... 
If you have a tuya hub, you can test it simply...
I have a tuya hub.
There was clearly a "mmWave" sign on my order, but now the seller has taken it out.
This is an illustration of the mmWave radars ranges taken from here: Tuya Wifi Smart Human Presence Detector Smart Human Body Pir Sensor Radar Detector Microwave Motion Sensors Wireless Real-time - Pir Motion Sensor - AliExpress
An interesting 24 GHz radar appeared on AliExpress, unfortunately, only WiFi / BT versions at the moment. Usually, the Zigbee versions follow several months later.
What should 'fretting detection' mean ???
I'm interested in this product, so I put it in the cart.
When I saw your explanation, I mistook it for this product at first.
This 24 uses the frequency band in the middle of the existing Toya product 5.8 and Fp1 60.
I wonder if there is a plan to use Wi-Fi and it locally on Hubitat.
The product you are describing seems to use the same app as the sensor you have. Then there is a possibility that sensing is not immediate. A little bit of delay...
Wait, the seller promised to check with the R&D on their plans for a Zigbee version.
Unfortunately, no WiFi devices can talk directly to Hubitat. But, cloud integration is available : [BETA] Tuya Cloud Driver (Limited device support)
And it is very fast! (when the cloud connection is available, of course ).
No, it is different - the seller sent me this screenshot :
Perhaps, they are talking about a restless situation.
It's 24 Ghz, Zigbee, but it's a little expensive.
Looking at this video, it looks similar to FP1.
Download the Hubitat app
