How do Tuya vibration sensors communicate with the cloud? Wireshark does not detect any communication with the sensor's MAC or IP other than DHCP and ARP. And the sensor is working.
Bluetooth doesn't work because I specifically disabled it on my phone and disconnected it from my home Wi-Fi network.
How does it work?
The sensor is Wi-Fi, I don't have any Tuya gateways at home, just a regular router.
It sounds like you ran Wireshark on another PC connected to the same network. In both Ethernet and Wi-Fi, you will not see any unicast traffic unless it is specifically sent to your MAC address. In modern Ethernet the switches will literally not send it towards you (they learn which MACs are connected to which Ethernet ports), while on Wi-Fi you're not guaranteed to physically receive the signal, and the network adapter will filter it out if you do.
(The filtering on Wi-Fi can be disabled using "monitor mode" but there's also no guarantee that you'll receive the signal, e.g. due to beamforming and other features, or simply due to being on the wrong frequency band... and you won't be able to decrypt it anyway, as WPA gives each client a different encryption key.)
So in order to see the traffic of another device, you need to explicitly put yourself in its path: either you do the capture on your regular router (some do have tcpdump), or you set up another router which can do the packet capture, or you do some kind of ARP spoofing to make the sensor think that your PC is the router, or you get a second Ethernet card and set up the PC as a bridge that all traffic would pass through, etc.
