Roboust Network connectivity

Question

I want to run a headless (no monitor and keyboard) Pi 3a in the somewhat fluent environment (at home, in an Artist’s studio, on the attic of an cathedral). The Pi is controlling some Christmas displays via DMX.

I want always be able to connect to the Pi via local WiFi/ssh for administration. I also want the Pi to connect to loco we see when possible.

So my goal book at somethings like:

1. Run an AP on the with 10.0.0.1 as the Adress. DHCP service for 10.0.0.0/24 Would be a nice bonus.

2. Also connect the build-in WiFi as a client to a known AP (if available).

this seems to be unusual combination. Although to me it looks highly desirable in all headless IoT scenarios.

Any suggestions on how to approach this?

Answer 1

With the built-in wifi-device of a Raspberry Pi it is possible to create an access point together with an uplink client connection. This can be done with creating a virtual interface ap0 (or what name do you like) from the physical interface wlan0. Because the virtual interface ap0 depends on wlan0 it is a bit sophisticated to manage its initialization in the correct order. But how to do it you can have a look at
Access point as WiFi router/repeater, optional with bridge

Answer 2

This would seem to be much more feasible with a second pi. Perhaps just an additional microcontroller to distribute the tasks that can't adequately be serviced by a single pi.