Fadecandy driver

ROS node for controlling LEDs via a fadecandy board. Uses python-usb to talk directly to the board, so it doesn’t need the fadecandy server - there are no dependencies on anything in the fadecandy repo. All you should need is a fadecandy board with fadecandy firmware on it.

Nodes

fadecandy_node

Parameters

• ~restart_patience: Driver restart patience when no connection could be established (default=1.)

Topics

Subscribers

• set_leds (fadecandy_msgs/LEDArray): Leds reference

Publishers

• diagnostics (diagnostic_msgs/DiagnosticStatus): Serial + connection status diagnostics

How to run

Start the node. Depending on permissions, this may need to run as root to talk to the USB device.

rosrun fadecandy_driver fadecandy_node

To make sure everything is working, you can send a test pattern using the example client script.

rosrun fadecandy_driver example_client

Note about how the LEDs are addressed

The fadecandy board has 8 pairs of outputs, numbered 0-7 on the PCB. Each of these can control a single Neopixel LED strip of up to 64 LEDs. In the LEDArray mesage, you can specify color outputs for an arbitrary number of strips. If the “strips” array in the LEDArray has length N, those colors are applied to the first N strips, starting with strip 0 on the board. So if you wanted to provide colors for just strip 0 and strip 5, you would need to include three empty LEDStrip messages in the “strips” message between them.

Within each LEDStrip message you provide a list of color values for each LED. If colors for less than 64 LEDs are provided, the rest are set to (0,0,0) (completely off). Also, the “a” (alpha) values of the colors aren’t used.

Finally, the fadecandy board doesn’t have any way of knowing how many strips are attached or how long they each are. It just pushes out 64 values for each of the 8 strips.

Configuring linux device permissions

By default, access the Fadecandy USB device in linux using libusb requires running as root. To fix this, copy the rules file from the udev directory of this package into /etc/udev/rules.d.

sudo cp udev/10-fadecandy.rules /etc/udev/rules.d/

Now reload the udev rules.

sudo udevadm control --reload-rules && udevadm trigger

If you have the Fadecandy device plugged in, unplug and replug it. Then make sure that your user has been added to the dialout group. Now you should be able to run without needing root!

Changelog for package fadecandy_driver

0.2.2 (2021-05-17)

• fix: usb interface number (#24)
• Contributors: Jad Haj Mustafa

0.2.1 (2021-04-20)

• chore(package.xml): Update maintainers
• Contributors: Rein Appeldoorn

0.2.0 (2021-04-19)

• Feat/refactor to c++ (#20) Co-authored-by: jad <<jad.hajmustafa@eurogroep.com>> Co-authored-by: Rein Appeldoorn <<reinzor@gmail.com>>
• Merge pull request #17 from eurogroep/fix/handle-reconnections fix: Handle reconnections properly
• fix(diagnostics): Publish before first connect
• Merge pull request #15 from eurogroep/fix/remove-fadecandy-util-unused-file fix: remove unused fadecandy_util.py
• fix: Handle reconnections properly Release the USB device and restart the driver when an IOError has been raised while sending to the USB device. This way, we can recover from unplugging and pluggin the USB device.
• fix: remove unused fadecandy_util.py
• Contributors: Catherine Wong, Jad Haj Mustafa, Rein Appeldoorn

0.1.3 (2020-11-02)

• Merge pull request #13 from eurogroep/fix/noetic-python3-struct-pack: fix(Noetic/Python3): Struct packing
• Contributors: Rein Appeldoorn

0.1.2 (2020-07-06)

• Merge pull request #10 from eurogroep/chore/log-io-error chore: log IO error
• Merge pull request #9 from eurogroep/fix/rospy-shutdown fix(shutdown): Shutdown gracefully when no connection was set-up
• Contributors: Rein Appeldoorn

0.1.1 (2020-06-03)

• Merge pull request #7 from jonbinney/python3-fixes Fixes for python3/noetic compatibility
• Contributors: Jon Binney

0.1.0 (2020-05-28)

• Initial release.