Why the tag has two boards

Our first tag used one ESP32 for everything, and in testing it kept dropping data. A Wi-Fi scan takes over the radio for 10 to 25 seconds, and the secure connection to our server timed out while it waited.

No firmware change could fix that, because the chip only has one radio. So we split the job: one board only scans, the other only talks to the server, and one wire connects them. After that, we didn’t see a single timeout in any test.