Raspberry Pi 5 Bluetooth Automatic Pairing (Without Pin Code Authentication)

This guide provides steps to set up automatic Bluetooth pairing on a Raspberry Pi 5 without using pin codes for authentication. After these settings, your RPI becomes a bluetooth device like headset/speaker, where you can connect automatically without using any UI.

Requirements

1) Install bluez and bluez-tools packages from apt first.

sudo apt-get install bluez && sudo apt-get install bluez-tools

NOTE: After installation, you can test no-pin connection manually via this command:

sudo bt-agent -c NoInputNoOutput

2) Change Bluetooth configurations.

Open dbus.org.bluez.service file.

sudo nano /etc/systemd/system/dbus.org.bluez.service

Edit ExecStart line and add ExecStartPost line to the file.

...
ExecStart=/usr/libexec/bluetooth/bluetoothd -C
ExecStartPost = /usr/bin/sdptool add SP
...

Steps to Auto Start Bluetooth Connection

Step 1. Create AutoStart Folder

Create an AutoStart folder in the Home directory.

mkdir ~/AutoStart

Step 2. Create an Executable Script

Next, create an executable script named bluetooth-pair.sh inside /Home/AutoStart.

touch /Home/AutoStart/bluetooth-pair.sh && chmod +777 /Home/AutoStart/bluetooth-pair.sh

Step 3. Script Content

Add your Bluetooth pairing script content to bluetooth-pair.sh file.

#!/bin/bash

sudo bluetoothctl << EOF
power on
discoverable on
pairable on
agent NoInputNoOutput
default-agent
scan on
EOF

sudo bt-agent -c NoInputNoOutput & sudo rfcomm watch hci0

Step 4. Auto-Run Script on Boot

To ensure this script runs automatically at every power cycle, add the following command to the /etc/rc.local file just before the Exit 0 command:

To edit the rc.local file, use:

sudo nano /etc/rc.local

While inside rc.local file, add sudo sh /home/pi/AutoStart/bluetooth-pair.sh line before Exit 0:

...

sudo sh /home/pi/AutoStart/bluetooth-pair.sh

Exit 0

NOTE: You can also add all commands above directly to the rc.local file, but this is more loosely-coupled way. This may also work in RPI 4.

NOTE: Added bt_writer.py and bt_reader.py files for online testing via Serial Bluetooth Terminal application in Android phones.

idincern/rpi5-bluetooth-autopair