Communicating over UART0 with HCI uart BLE dongle

I am trying to use the BluePy Scanner on a Raspberry Pi 3 B+ with a nRF52840-Dongle programmed as a Bluetooth: HCI-uart.

I am able to get the Bluepy Scanner code to work with the onboard BLE, but I am so far unable to get it to communicate with the Bluetooth HCI dongle that is attached to the UART0. I have connected UART0_TXD (GPIO14), UART0_RXD (GPIO15), UART0_CTS (GPIO16), and UART0_RTS (GPIO17).

How do I go about attaching a HCI ble device to the RPi’s UART and then use it in my python scanner program?

The nRF52840-Dongle has the following default UART settings.

  • Baudrate: 1Mbit/s
  • 8 bits, no parity, 1 stop bit
  • Hardware Flow Control (RTS/CTS) enabled

Following is my bluepyScanner code.

from bluepy.btle import Scanner, DefaultDelegate

class ScanDelegate(DefaultDelegate):
    def __init__(self):

    def handleDiscovery(self, dev, isNewDev, isNewData):
        if isNewDev:
            print("Discovered device", dev.addr)
        elif isNewData:
            print("Received new data from", dev.addr)

scanner = Scanner().withDelegate(ScanDelegate())
devices = scanner.scan(10.0)

for dev in devices:
    print("Device {} ({}), RSSI={} dB".format(dev.addr, dev.addrType, dev.rssi))
    for (adtype, desc, value) in dev.getScanData():
        print("  {} = {}".format(desc, value))
        with open('bluepyscanlog.txt', 'a') as the_file:
            the_file.write("{}={}\n".format(desc, value))

And the Dockerfile.template for bluepyScanner.

FROM balenalib/%%BALENA_MACHINE_NAME%%-python:3-stretch-run

# enable container init system.

# use `install_packages` if you need to install dependencies,
# for instance if you need git, just uncomment the line below.
# RUN install_packages git
RUN pip install --upgrade pip
RUN apt-get update && apt-get install -yq --no-install-recommends build-essential 
RUN install_packages \
    build-essential \
    bluez \
    python-dbus \
    python-dev \

# Set our working directory
WORKDIR /usr/src/bluepyScanner

# Copy requirements.txt first for better cache on later pushes
COPY requirements.txt requirements.txt

# pip install python deps from requirements.txt on the build server
RUN pip3 install -r requirements.txt

# This will copy all files in our root to the working  directory in the container
COPY . ./

# Enable udevd so that plugged dynamic hardware devices show up in our container.

# will run when container starts up on the device
CMD ["python3","-u","src/"]

The only item in requirements.txt is


Following is my docker-compose.yml

version: '2.1'

        privileged: true
        restart: always
        build: ./bluepy_scanner
            - "/dev/ttyS0:/dev/ttyS0"
        network_mode: host
            - NET_ADMIN
            io.balena.features.supervisor-api: '1'
            io.balena.features.dbus: "1"
            io.balena.features.kernel-modules: "1"
            io.balena.features.firmware: "1"
            io.balena.features.balena-api: "1"
        build: ./wifi-connect
        network_mode: "host"
            io.balena.features.dbus: '1'
            - NET_ADMIN
            DBUS_SYSTEM_BUS_ADDRESS: "unix:path=/host/run/dbus/system_bus_socket"

I have set the following Device configurations.

Hi there and thanks for bringing this up!

As this falls a little outside the scope of balenaCloud, let’s see if any of our fantastic forums members have ideas about how to get that dongle up and running.

Thanks. I moved it over to BalenaOS.

Do any of the Balena support team for #balena-os have any thoughts or ideas for a solution to this issue?

@xginn8, should I repost this to #balena-os, since I originally posted in #balena-cloud and then just changed the category to #balena-os?