[eqvinox]

The only things with a chance at succeeding in this space are putting USB-serial directly on the board + USB-C, or alternatively bluetooth classic RFCOMM profile. (The latter is a very long shot.)

Apart from that, this doesn't even touch upon the various voltage levels for logic-level serial ports, or the question of whether to Vref or not to Vref. (Or RTS/CTS.)

[russdill]

Microcontrollers that support BLE are getting so cheap this really is becoming an option. Hopefully with some button that activates it.

[markrages]

RFCOMM is old Bluetooth, not BLE.

Nordic has a serial-over-ble profile, but it is not standard like RFCOMM.

[eqvinox]

Indeed… a fact making me really sad about BLE :(. The Nordic profile might become widespread enough to become de-facto standard, but AFAIK isn't quite widespread enough yet, i.e. people are still homebrewing almost the same thing(?)

[russdill]

I mean, sure there are still rough edges, but it's not like rs232 over Juliet is some widely supported standard.

There are Android apps that support serial over ble

[dzhiurgis]

Home Assistant and it’s relative esphome just added serial-proxy support. Basically you can use any esp32 board to add smart capabilities for old devices via serial port.