Does anybody have any reliable information on when and under what circumstances you need FCC and/or CE certifications? If you build out of Gadgeteer, does the final device need any certifications? If you build a custom mainboard and use pre-certified radio modules, does it need certifications? Are there self-certifications pathways available?
EDIT: And is there any exception for industrial devices vs consumer devices?
This is just my fast answer.
FCC is required if the device is intended to transmit anything on any RF frequency that is sold to a consumer for use. It is not required if the consumer builds the item themselves. For example, a software defined radio that can broadcast, cannot be certified. Therefore the manufacturer shall not sell such things to consumers. If the consumer assembles it, then it’s OK. In my country, you can’t even import RF equipment without presenting the intended license to customs at the time of import.
Modules that come with an FCC ID (eg esp8266 modules) are already certified and are cleared for use.
Anything that does not operate on the unlicensed frequencies (e.g. 900 mhz and 2.4ghz) requires a further license by the consumer to use, on top of the FCC certification that the manufacturer would have had to get.
Sorry - I should have been more clear that I was looking for reliable firsthand/‘direct experience’ information relevant to the types of boards used or created here.