Hello @drlaurie,
I helped with your project and It’s great to hear from you! I hope all is well and you’ve found the device and it’s content useful.
The contents of this post on our forums applies to the V3 device that you have as well.
Since the device produces a WIFI signal, you can use a WIFI range extenders to extend the range. For a concrete building, you may want to look at “mesh” WIFI range extenders to get better coverage. Mesh means that each range extender will connect to another which allows you to keep extending the range. This would help you with concrete or getting access to different floors and is what I would suggest trying. If you need help with this method please let me know.
James