LED subsystem: CANdle-driven status lighting

LEDSubsystem drives a CTRE CANdle (CAN ID CANDLE_ID = 40) to communicate robot state to drivers and human players via color and animation. All LED output runs through three internal patterns: SOLID, ALTERNATE, and RAINBOW.

LED modes

Mode	Color	R, G, B	Pattern	Trigger condition
`DEFAULT`	Purple	255, 0, 255	Solid	Default teleop state
`INTAKE`	Blue	0, 0, 255	Solid	Left trigger held (intaking)
`LAUNCHING`	Yellow ↔ Red	255, 255, 0 / 255, 0, 0	Alternating (0.25 s interval)	Right trigger held, spinning up
`LAUNCH`	Green	0, 255, 0	Solid	Launcher at target, feeding
`CLIMB`	Orange	255, 128, 0	Solid	Climb mode active
`RAINBOW`	Rainbow	—	Rainbow animation	Autonomous mode
`DISABLED`	Off	0, 0, 0	Solid	Robot disabled

The CANdle controls a strip of 200 LEDs (END_INDEX = 200). The SolidColor controller and RainbowAnimation both address the full range from index 0 to 199.

Pattern types

LEDPattern is an internal enum with three variants:

SOLID

Applies a single RGBWColor to all LEDs via a SolidColor control request. Used for DEFAULT, INTAKE, LAUNCH, CLIMB, and DISABLED.

ALTERNATE

Toggles between two colors (primaryColor and secondaryColor) on a configurable interval. Currently used by LAUNCHING (yellow ↔ red, 0.25 s). The toggle runs in periodic().

RAINBOW

Issues a RainbowAnimation request to the CANdle at 100 Hz frame rate, full brightness (1.0), forward direction. Used during autonomous.

Rainbow animation configuration

rainbowAnimation
    .withBrightness(1.0)
    .withDirection(AnimationDirectionValue.Forward)
    .withFrameRate(Units.Hertz.of(100));

The animation object is created once at construction and applied via candle.setControl(rainbowAnimation).

setMode

setMode(LEDMode mode) is idempotent — it exits early if the requested mode matches the current mode:

public void setMode(LEDMode mode) {
    if (mode == currentMode) return;
    currentMode = mode;
    switch (mode) {
        case INTAKE    -> setSolid(INTAKE_COLOR);
        case CLIMB     -> setSolid(CLIMB_COLOR);
        case DEFAULT   -> setSolid(DEFAULT_COLOR);
        case LAUNCH    -> setSolid(LAUNCH_COLOR);
        case LAUNCHING -> setAlternating(LAUNCH_PREP_COLOR, LAUNCH_PREP_COLOR_TWO, 0.25);
        case DISABLED  -> setSolid(OFF);
        case RAINBOW   -> setRainbow();
    }
    publishState();
}

flashCommand

flashCommand(RGBWColor color, int times, double interval) returns a Command that blinks the LEDs times times at the given interval (seconds per half-cycle), then restores the previous mode:

public Command flashCommand(RGBWColor color, int times, double interval) {
    return Commands.sequence(
            Commands.repeatingSequence(
                    Commands.runOnce(() -> setHardwareColor(color)),
                    Commands.waitSeconds(interval),
                    Commands.runOnce(() -> setHardwareColor(OFF)),
                    Commands.waitSeconds(interval))
                .withTimeout(times * interval * 2),
            Commands.runOnce(() -> {
                LEDMode saved = currentMode;
                currentMode = null;
                setMode(saved);
            }))
        .withName("Flash LEDs");
}

Controls.java uses this to flash orange 30 times at 0.1 s on a readyToShoot falling edge, and green 3 times at 0.2 s on the zero-subsystems start button.

Disabled behavior

periodic() checks RobotState.isDisabled() each cycle. When disabled, it forces setMode(LEDMode.DISABLED) — turning all LEDs off — regardless of the last teleop mode. When the robot re-enables, the ledsMode field in Controls.java restores the appropriate mode on the next periodic cycle.

NetworkTables topics

Topic	Type	Description
`/color/currentMode`	String	Name of the active `LEDMode`
`/color/currentPattern`	String	Name of the active `LEDPattern`
`/color/currentColor`	String	Hex color string (solid patterns only)
`/color/alternatingColors`	String	`“A:#rrggbb	B:#rrggbb”` (alternate pattern only)

Trigger conditions from Controls.java

Driver input	LED effect
Left trigger (hold)	`INTAKE` (blue)
Right trigger (hold) — spinning up	`LAUNCHING` (yellow ↔ red alternating)
Right trigger (hold) — at target	`LAUNCH` (green)
Start button (zero)	Flash green 3×
`readyToShoot` falling edge	Flash orange 30×
Robot disabled	`DISABLED` (off)
Default teleop	`DEFAULT` (purple)

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Configuration & Tuning

LED subsystem: CANdle-driven status lighting

LED modes

Pattern types

SOLID

ALTERNATE

RAINBOW

Rainbow animation configuration

setMode

flashCommand

Disabled behavior

NetworkTables topics

Trigger conditions from Controls.java

​LED modes

​Pattern types

SOLID

ALTERNATE

RAINBOW

​Rainbow animation configuration

​setMode

​flashCommand

​Disabled behavior

​NetworkTables topics

​Trigger conditions from Controls.java

LED modes

Pattern types

Rainbow animation configuration

setMode

flashCommand

Disabled behavior

NetworkTables topics

Trigger conditions from Controls.java