A Crazyflie 2.1 Brushless streaming IMU and AI-deck camera to rewire, via a patched crazyswarm2.

Real hardware: a Crazyflie 2.1 Brushless, a Crazyradio, and — for the camera — an AI-deck 1.1.

Topics

Topic	Type	Rate
/cf1/imu	sensor_msgs/Imu	50 Hz	Added by patch; upstream has no IMU topic
/cf1/pose	geometry_msgs/PoseStamped	10 Hz	Orientation valid, position is not
/cf1/status	crazyflie_interfaces/Status	1 Hz
/camera/image	sensor_msgs/Image	~8 Hz	324x244 mono8, over WiFi not the radio
/camera/camera_info	sensor_msgs/CameraInfo	~8 Hz	Placeholder intrinsics
/tf, /tf_static	tf2_msgs/TFMessage		world→cf1, cf1→cf1/camera

Setup

pixi run setup     # clone crazyswarm2 + motion_capture_tracking at pinned SHAs, apply patches/
pixi install

Usage

pixi run scan
pixi run server    # cflib backend; prefer it over server-cpp on Brushless,
                   # cflib tracks new hardware faster than crazyflie_cpp
pixi run camera    # requires joining the deck's AP first
pixi run viz       # rewire record --all

scripts/arm_cycle.py arms for a fixed duration then disarms. Brushless needs arming before the motors spin; it spins the props.

Development

src/ is gitignored and reset by pixi run setup. Never edit it directly — change the patch:

git -C src/crazyswarm2 diff -- <paths> > patches/000N-<name>.patch
pixi clean --build && pixi install

pixi install on its own silently skips rebuilding edited source packages: it reports success, produces no .conda artifact, and leaves the stale copy in .pixi/envs/. Always pixi clean --build first and verify the change actually reached the env.

Patches

Patch
0001-macos-build-fixes	crazyflie-link-cpp's Findlibusb.cmake demands a static libusb-1.0.a on macOS, which conda-forge does not ship. conda's Eigen3 exports only the imported target, not EIGEN3_INCLUDE_DIRS. crazyflie_cpp and crazyflieLinkCpp were built but never installed, so the binaries dangled once the build tree went away
0002-imu-default-topic	Adds imu as a fifth default_topic, both backends (plus docs + commented example). No orientation: a firmware log block holds 26 bytes and six float32 uses 24, so the attitude estimate does not fit — hence orientation_covariance[0] = -1
0003-aideck-streamer-fixes	reshape(width, height) was transposed, and since 324×244 == 244×324 numpy accepted it silently and sheared the image. Bayer demosaic was applied to greyscale data. image_height said 324 where the HM01B0 is 244. Publishes mono8 rather than inflating 4× to RGBA. Broadcasts the camera's static transform. Publishes on receive instead of from a second timer, which was dropping ~⅓ of frames
0004, 0005	Per-package pixi.toml — upstream ships none

Gotchas

• The GAP8 serves one TCP client. Probing the port with nc first can leave the deck unwilling to serve the streamer. Let the node connect first.
• macOS drifts back to a network with internet, silently dropping the deck's AP. Check ifconfig en0 | grep "inet " for 192.168.4.x.
• cflib 0.1.32 caps packaging<26. Without the pin the solve takes 26.x, silently downgrades cflib to 0.1.17, and fails at runtime with 'Crazyflie' object has no attribute 'fully_connected'.

For AI-deck firmware flashing, follow Bitcraze's guide — use the _with_ap binary so the deck broadcasts its own access point.

Limitations

No positioning deck, so stabilizer.estimator is 1 (complementary) — Kalman diverges without a position reference, reading tens of metres while stationary. Position in /cf1/pose is meaningless and takeoff/land/go_to/cmd_position/cmd_hover are unusable. Yaw drifts; the 2.1 has no magnetometer. Fit a Flow deck v2, Lighthouse, Loco or mocap, then set estimator: 2.

Camera intrinsics are a placeholder, not a calibration — fx/fy inherited from upstream's 324×324 values, cx/cy the image centre, distortion assumed zero despite visible barrel distortion. The mount offset in config/aideck_streamer.yaml is likewise an estimate.

IMU covariances are all zeros — "unknown" per sensor_msgs/Imu. Fine for visualization, not for an EKF.

backend:=sim does not work — crazyflie_sim imports cffirmware, a separate SWIG build that is not packaged here.