Raspberry Pi Bluetooth

Raspberry Pi with Bluetooth is available in two variants:

• Raspberry Pi 3 & 4 with integrated Bluetooth module
• Raspberry Pi with external Bluetooth adapter via USB 
•  raspberry pi Bluetooth receiver

The integrated Bluetooth module is Bluetooth Classic and Low Energy (Bluetooth 4.1, BLE).

Since Raspbian Jessie from 2016-05-10, the software-side support for Bluetooth exists by default. For this purpose, the desktop environment LXDE in the taskbar has a graphical tool for managing the internal and external Bluetooth components. This allows you to select the desired device and establish a Bluetooth connection.

Install Bluetooth support for Raspberry Pi 
If you have an older image, then you have to install the support.

sudo apt-get update
sudo apt-get upgrade
sudo apt-get install pi-bluetooth

Then check if Bluetooth support is running:

sudo systemctl status bluetooth

Continue if “Active: active (running)”.

Display Bluetooth interfaces:

 hciconfig

The interface “hci0” should exist.
Install Bluetooth Connection Manager
If not already available, you can install a Bluetooth connection manager for the graphical desktop interface:

sudo apt-get install blueman

This makes it easy to establish and manage Bluetooth connections to other devices.

Disable Bluetooth and WiFi on the Raspberry Pi 3
The Raspberry Pi 3 has Bluetooth and WLAN integrated. But for some applications, one or both is superfluous. For example, because you want to use an external adapter. In that case you can switch off both.

Solution 1: Turn off Bluetooth in the boot configuration
Bluetooth can be switched off in the boot configuration (from kernel 4.1.19).

sudo nano /boot/config.txt

Here you enter the following line:

dtoverlay = pi3-disable-bt

Save, close and restart.

Solution 2: Turn off Bluetooth and or WLAN
Bluetooth can also be switched off by preventing the driver from being charged.
To do this, open a configuration file:

sudo nano /etc/modprobe.d/raspi-blacklist.conf

Add the following lines:

# Switch off WLAN
blacklist brcmfmac
blacklist brcmutil

#blacklist cfg80211
#blacklist rfkill

# Turn off Bluetooth
blacklist btbcm
blacklist hci_uart

Save and close.
As a test, the modules can also be unloaded with the command

sudo modprobe -r {MODULE}

In addition, you have to turn off a service that otherwise tries to use Bluetooth.

sudo systemctl disable hciuart

After that a restart is necessary.
Note: Measurements have shown that the radio chip still buzzes despite being deactivated by the software.