# Crazyflie 2.1

PX4 does not manufacture this (or any) autopilot. Contact the [manufacturer](https://www.bitcraze.io/) for hardware support or compliance issues.

PX4 support for this flight controller is [experimental](../flight_controller/autopilot_experimental.md).

WARNING

Crazyflie 2.1 is only able to fly in Manual/Stabilized mode.

The Crazyflie line of micro quads was created by Bitcraze AB. An overview of the Crazyflie 2.1 can be found here (opens new window).

Crazyflie2 Image

# Quick Summary

Note

The main hardware documentation is here (opens new window)

  • Main System-on-Chip: STM32F405RG
    • CPU: 168 MHz ARM Cortex M4 with single-precision FPU
    • RAM: 192 KB SRAM
  • nRF51822 radio and power management MCU
  • BMI088 3 axis accelerometer / gyroscope
  • BMP388 high precision pressure sensor
  • uUSB connector
  • On-board LiPo charger with 100mA, 500mA and 980mA modes available
  • Full speed USB device interface
  • Partial USB OTG capability (USB OTG present but no 5V output)
  • 8KB EEPROM

# Where to Buy

The vehicle can be purchased here: Crazyflie 2.1 (opens new window) (store.bitcraze.io)

Useful peripheral hardware includes:

# Assemble Crazyflie 2.1

# Flashing PX4

Note

These instructions have only been tested on Ubuntu.

After setting up the PX4 development environment, follow these steps to install the PX4 Autopilot on the Crazyflie 2.1:

  1. Download the source code of the PX4 Bootloader:

    git clone https://github.com/PX4/Bootloader.git --recurse-submodules
    
  2. Navigate into the top directory of the source code and compile it using:

    make crazyflie21_bl
    
  3. Put the Crazyflie 2.1 into DFU mode by following these steps:

    • Ensure it is initially unpowered.
    • Ensure battery is disconnected.
    • Hold down the reset button (see figure below...). Crazyflie2 Reset Button
    • Plug into computer's USB port.
    • After a second, the blue LED should start blinking and after 5 seconds should start blinking faster.
    • Release button.
  4. Install dfu-util:

    sudo apt-get update
    sudo apt-get install dfu-util
    
  5. Flash bootloader using dfu-util and unplug Crazyflie 2.1 when done:

    sudo dfu-util -d 0483:df11 -a 0 -s 0x08000000 -D ./build/crazyflie21_bl/crazyflie21_bl.bin
    

    When powering on the Crazyflie 2.1 the yellow LED should blink.

  6. Download the source code of the PX4 autopilot:

    git clone https://github.com/PX4/PX4-Autopilot.git
    
  7. Navigate into the top directory of the source code and compile it using:

    cd PX4-Autopilot/
    make bitcraze_crazyflie21_default upload
    
  8. When prompted to plug in device, plug in Crazyflie 2.1. The yellow LED should start blinking indicating bootloader mode. Then the red LED should turn on indicating that the flashing process has started.

  9. Wait for completion.

  10. Done! Calibrate the sensors using QGroundControl (opens new window).

# Flashing Original Bitcraze Firmware

  1. Download the latest Crazyflie 2.1 bootloader (opens new window)
  2. Put the Crazyflie 2.1 into DFU mode by following these steps:
    • Ensure it is initially unpowered.
    • Ensure battery is disconnected.
    • Hold down the reset button.
    • Plug into computer's USB port.
    • After a second, the blue LED should start blinking and after 5 seconds should start blinking faster.
    • Release button.
  3. Flash bootloader using dfu-util and unplug Crazyflie 2.1 when done:
    sudo dfu-util -d 0483:df11 -a 0 -s 0x08000000 -D cf2loader-1.0.bin
    
    When powering on the Crazyflie 2.1 the yellow LED should blink.
  4. Install the latest Bitcraze Crazyflie 2.1 Firmware using this (opens new window) tutorial.

# Wireless Setup Instructions

The onboard nRF module allows connecting to the board via Bluetooth or through the proprietary 2.4GHz Nordic ESB protocol.

Connecting via MAVLink:

  • Use a Crazyradio PA alongside a compatible GCS.
  • Download the crazyflie-lib-python source code:
    git clone https://github.com/bitcraze/crazyflie-lib-python.git
    

Note

We will use cfbridge.py (opens new window) to setup a wireless MAVlink communication link between Crazyflie 2.1 (flashed with PX4) and QGroundControl. Cfbridge enables QGroundControl to communicate with the crazyradio PA. The C based cfbridge (opens new window) is currently experiencing data loss issues, which is why we have chosen to use cfbridge.py.

  • Make sure you have set the udev permissions to use the USB Radio. To do this, follow the steps listed here (opens new window) and restart your computer.
  • Connect a Crazyradio PA via USB.
  • Build a virtual environment (local python environment) (opens new window) with package dependencies using the following method:
    pip install tox --user
    
  • Navigate to the crazyflie-lib-python folder and type:
    make venv
    
  • Activate the virtual environment:
    source venv/bin/activate
    
  • Install required dependencies:
    pip install cflib
    pip install -r requirements.txt
    

To connect Crazyflie 2.1 with crazyradio, launch cfbridge by following these steps:

  • Power off and power on Crazyflie 2.1 and wait for it to boot up.
  • Connect a Crazyflie radio device via USB.
  • Navigate to the crazyflie-lib-python folder.
  • Activate the environment:
    source venv/bin/activate
    
  • Navigate to the examples folder:
    cd examples
    
  • Launch cfbridge:
    python cfbridge.py
    

Note

Cfbridge by default tries to initiate the radio link communication on channel 80 and with crazyflie address 0xE7E7E7E7E7. If you are using multiple crazyflies and/or crazyradios (opens new window) in the same room and want to use a different channel and/or address for each, first connect the crazyflie with QGroundControl via a USB cable and change the syslink parameters (channel, address) in QGroundControl. Next, launch the cfbridge by giving the same channel and address as the first and second arguments respectively, e.g: python cfbridge.py 90 0x0202020202

  • Open QGroundControl.
  • After using cfbridge, you can deactivate the virtualenv if you activated it by pressing CTRL+z. Most of the time, launching cfbridge again from the same terminal doesn't connect to crazyflie, this can be solved by closing the terminal and relaunching cfbridge in a new terminal.

TIP

If you change any driver in crazyflie-lib-python (opens new window) or if launching cfbridge in a new terminal does not find crazyflie, you can try navigating to the crazyflie-lib-python folder and run the script below to rebuild cflib.

make venv

Note

The Joystick menu in QGC, only appears after you connect the controller to the PC (for example a Playstation 3 controller).

QGC joystick menu

# Hardware Setup

Crazyflie 2.1 is only able to fly in Stabilized mode.

In order to log flight details, you can mount SD card deck on top of crazyflie as shown below:

Crazyflie SDCard

# Using FrSky Taranis RC Transmitter as Joystick

If you already own a Taranis RC transmitter and want to use it as a controller, it can be configured as a USB Joystick:

  • Create a new model in Taranis.

    Taranis - new model

  • In MODEL SETUP menu page, turn off both internal and external TX modules.

    Taranis - model setup

  • In OUTPUTS menu page (also called “SERVOS” page in some Taranis transmitters), invert Throttle (CH1) and Aileron (CH3).

    Taranis - outputs

To use Taranis switches to arm/disarm and switch to different flight modes:

  • In Taranis UI MIXER menu page, you can assign the switches to any channel in the range channel 9-16 which map to the buttons 0-7 in the QGroundControl Joystick setup. For example, Taranis “SD” switch can be set to channel 9 in Taranis UI:

    Taranis switch setup

  • Connect Taranis to PC with a USB cable and Open QGroundControl.

  • In QGroundControl Joystick Setup, you can see the buttons turning yellow when you switch them on. For example, channel 9 in Taranis maps to button 0 in QGroundControl Joystick setup. You can assign any mode to this button e.g. Altitude mode. Now when you lower the switch "SD", flight mode will change to Altitude.

    Joystick setup

# ROS

To connect to Crazyflie 2.1 via MAVROS:

  • Start up cfbridge using the above instructions.
  • Change the UDP port QGroundControl listens to:
    • In QGroundControl, navigate to Application Settings > General and uncheck all the boxes under Autoconnect to the following devices.
    • Add in Comm Links a link of type UDP, check the Automatically Connect on Start option, change the Listening Port to 14557, add Target Hosts: 127.0.0.1 and then press OK.
  • Make sure you have MAVROS (opens new window) installed.
  • Start MAVROS with command:
    roslaunch mavros px4.launch fcu_url:="udp://:14550@127.0.0.1:14551" gcs_url:="udp://@127.0.0.1:14557"
    
  • Restart QGroundControl if it doesn't connect.

# Flying