Replicating the REPL over an HC-05 Bluetooth connection on the PICO RP2040

[freemansoft]

It is only two lines of code to enable serial and the REPL over the HC-05 Bluetooth adapter. People have been doing this for a while but I wanted to capture the two lines of code required for the RP2040. This assumes an HC-05 at the default data rate on UART0

u = machine.UART(0, baudrate=9600)
os.dupterm(u)

Bluetooth supports virtual serial ports in the same way USB devices can. Many cheap Bluetooth adapters device present themselves as virtual serial ports after a successful pairing. We can then open the virtual serial port just like any other to read and write data as if it was a physical connection.

The serial port can be used for streaming data or to run the REPL over the Bluetooth virtual serial port. I enable the REPL to do troubleshooting and tweaking which still leaves it available for data communication. The truly awesome RP2040 has two software UARTS in addition to the USB serial connection. We can connect either of these to a serial RX/TX Bluetooth adapter. That is simple as shown below.

Replicating the REPL across a Bluetooth Link Blog Article

[freemansoft]

Failure is a learning experience too.

It turns out my HC-05 was an HC-06 and that is the reason I couldn't get it into command mode as expected. https://joe.blog.freemansoft.com/2023/01/fail-my-old-hc-05-bluetooth-module-was.html