Bluetooth Serial on Raspberry Pi

To enable serial over bluetooth on the raspberry pi, do these.

1. Restart bluetoothd with the -C flag to “provide deprecated command line interfaces”.

To do this, you can kill bluetoothd and restart it on the command line, or edit /etc/systemd/system/bluetooth.target.wants/bluetooth.service

Add -C like this:

ExecStart=/usr/lib/bluetooth/bluetoothd -C

Then restart bluetoothd

sudo systemctl restart bluetooth

2. Advertise a serial port service on your raspberry pi

$ sudo sdptool add SP
Serial Port service registered
$

3. Connect/pair your client to the raspberry pi

Do this by making the raspberry pi discoverable. You can either do this on the GUI, or

$ bluetoothctl
[NEW] Controller B8:27:EB:15:63:10 raspberrypi [default]
[bluetooth]# discoverable on
Changing discoverable on succeeded
[CHG] Controller B8:27:EB:15:63:10 Discoverable: yes
[bluetooth]# quit
[DEL] Controller B8:27:EB:15:63:10 raspberrypi [default]
pi@raspberrypi:~ $

I used my mac to connect to the raspberry pi, so on the mac, I used the GUI.

4. Start rfcomm. This watches hci0 and listens so that it can run the command, which is getty rfcomm0 115200 vt100 -a pi

The command gives you a shell on the raspberry pi

$ sudo rfcomm watch hci0 1 getty rfcomm0 115200 vt100 -a pi
Waiting for connection on channel 1

5. Connect to the raspberry pi from the client.

On my mac, I used

screen /dev/cu.raspberrypi-SerialPort 115200

/dev/cu.raspberrypi-SerialPort appears after you pair successfully with the raspberry pi. If you didn’t advertise the serial port service, this device will not appear on the mac.