Harry Bloomfield wrote:

The gadget is inside a sealed container. It is actually an electronic
hydrometer for my homebrew.

It's not that simple to "sniff" wifi traffic, you're looking at e.g.
linux with a wifi dongle in monitor mode, unless you can "rig" an extra
access point to force the device through ethernet and sniff it there on
a switch with mirror port, in short if you knew how to force it to do
any of those you wouldn't be asking here ...