DroneCAN Lights

PX4 can control external LEDs on a connected DroneCAN peripheral using the standard DroneCAN LightsCommand message.

Up to 2 lights are supported. These can show system status colours, a fixed colour (used for indicating aircraft orientation), or switch between both depending on arm state.

Пристрої, що підтримуються

Any DroneCAN peripheral implementing the standard LightsCommand message type should work.

The following have been tested:

• Vertiq ESC LED add-ons: Each ESC exposes two light IDs — one RGB (for status) and one white. The light_id for each is calculated as esc_index × 3 + BASE_ID, where BASE_ID is 1 for RGB and 2 for white. See Vertiq for other ESC setup details.

Конфігурація PX4

1. Set up DroneCAN as described in DroneCAN (UAVCAN_ENABLE ≥ 2).
2. Set UAVCAN_LGT_NUM to the number of lights (1 or 2). Then reboot and reopen the ground station so that parameters for the new instances become visible.
3. Set the light_id and light functions of each light:
   • UAVCAN_LGT_ID0 / UAVCAN_LGT_ID1: Set to a light_id value (as defined by the specific product).
   • UAVCAN_LGT_FN0 / UAVCAN_LGT_FN1: Choose the desired light function.
4. Set UAVCAN_LGT_MODE to control when fixed "orientation" colours activate.
5. Reboot for changes to take effect.

Light Functions

The functions of enabled lights are configured using UAVCAN_LGT_FN0 and UAVCAN_LGT_FN1, respectively. Each function is represented by a value that defines two behaviours: one when the activation mode is inactive and one when it is active.

Значення	Назва	When mode inactive	When mode active
0	Status/Status	System status colour	System status colour
1	Off/White	Off	White
2	Off/Red	Off	Red
3	Off/Green	Off	Зелений
4	Status/White	System status colour	White
5	Status/Red	System status colour	Red
6	Status/Green	System status colour	Зелений
7	Status/Off	System status colour	Off

Notes:

• The system status colours is the same LED pattern used by the flight controller's onboard status LED (e.g. red when disarmed, green when armed and ready).
• A fixed colour, commonly used to indicate aircraft orientation. For example it is a common convention to have a red light on the port side, green on starboard, or white to the rear. These colours do not change with flight controller state.
• For hybrid functions, such as Status/Red, the light shows the Status colour while the activation mode is inactive, then switches to the "fixed" light colour once the mode becomes active.

Activation Mode (UAVCAN_LGT_MODE)

The activation mode parameter (UAVCAN_LGT_MODE) controls when each light switches from its inactive to its active behaviour (configured with the Light function):

Значення	Значення
0	Always inactive (lights always show the inactive column)
1	Active when armed (default)
2	Active when prearmed or armed
3	Always active (lights always show the active column)