MacOS connecting to bluetooth module

Question

I have lots of issues connecting Mac OS Mojave to my sparksfun Bluetooth module RN-42.

I can pair my Bluetooth module to my Mac, but after several seconds, the connection goes away. However, for the several seconds that the connection stays, I'm trying to activate my Bluetooth module in command mode by typing in my dev folder:

cat -v tty.Bluetooth-Incoming-Port

Which is followed by the error:

cat: tty.Bluetooth-Incoming-Port: Resource busy

Furthermore, I also try to do (without any pairing beforehand):

cat -v tty.WiimoteRcvr-RNI-SPP 

Where Wiimote is the name of the Bluetooth module defined by the previous user.

cat: tty.WiimoteRcvr-RNI-SPP: Resource busy

This problem disappears, though, when I instead use a Bluetooth dongle. Now, I skip the step of pairing, and directly enter the command above and I successfully connect:

cat -v tty.WiimoteRcvr-RNI-SPP

From comment posted by OP - Resetting the Bluetooth Module on my computer fixed a lot of issues. However, cat and echo are broken now.

Questions:

Does anyone know why I have to use this Bluetooth dongle? Why can't my Mac sustain a Bluetooth connection to this bluetooth module? Other computers are fine. When should I pair to the name of the bluetooth module vs when to connect to tty.Bluetooth-Incoming-Port?

Also, how can I receive feedback? I'm trying to get output from the Bluetooth module, by echoing to it in one terminal, but cat isn't getting anything from the other terminal.

Answer 1

I've experienced the same problem connecting with ESP32 Module, and what I've seen is that in the Bluetooth Manager the connection goes away, but the device shows up in the terminal (ls /dev/tty.*).

In my case, when I do cat -v /dev/tty.DEVICENAME, prints all the expected output of the module, and I can send data via terminal too.