I love a good hack, and this one is great. Here is a project that allows you to upload data using Apple’s Find My network.
Apple’s Find My network is pretty cool. Apple devices can see other Apple devices around them, and upload information to Apple that owner of said devices can use to find their devices. It’s all done securely, and is really cool. This is how Apple’s new AirTags work, since they do not have any sort of wifi or cellular capability.