Manual

This function creates a LightringLeds message and populates the parameters.
We first stamp the message with the current time:
lightring_msg.header.stamp = this->get_clock()->now();
Then we set the override_system parameter to true so that our command overrides whatever
commands the Create® 3 is sending to the lightring.
lightring_msg.override_system = true;
Next, we populate the 6 LEDs in the leds array with whatever colours we want.
// LED 0
lightring_msg.leds[0].red = 255;
lightring_msg.leds[0].blue = 0;
lightring_msg.leds[0].green = 0;
// LED 1
lightring_msg.leds[1].red = 0;
lightring_msg.leds[1].blue = 255;
lightring_msg.leds[1].green = 0;
// LED 2
lightring_msg.leds[2].red = 0;
lightring_msg.leds[2].blue = 0;
lightring_msg.leds[2].green = 255;
// LED 3
lightring_msg.leds[3].red = 255;
lightring_msg.leds[3].blue = 255;
lightring_msg.leds[3].green = 0;
// LED 4
lightring_msg.leds[4].red = 255;
lightring_msg.leds[4].blue = 0;
lightring_msg.leds[4].green = 255;
// LED 5
lightring_msg.leds[5].red = 0;
lightring_msg.leds[5].blue = 255;
lightring_msg.leds[5].green = 255;