LED State Machine

Author

Braidan Duffy

Introduction

This class integrates the StateMachine superclass and defines some NeoPixel-specific functions. The OlympianESC evaluation board uses a NeoPixel RGB LED for user feedback. This includes showing connection and error states, motor controls, and identification testing. The color and pattern of the LED depends on the system state as discussed in the next section.

LED Colors and Patterns

The NeoPixel RGB LED can be commanded to show a practically infinite range of colors in 255 brightness steps. For the system states defined in state_machine.h, we can build a table for colors and patterns users can associate with each state:

System State	Color(s)	Pattern
IDLE_NO_CONNECTION	Yellow	Blinking
IDLE_WITH_CONNECTION	Yellow	Solid
PARTIAL_FORWARD	Green	Blinking
PARTIAL_REVERSE	Red	Blinking
FULL_FORWARD	Green	Solid
FULL_REVERSE	Red	Solid
DEVICE_IDENTIFY	White, Magenta	Blinking, alternating
MOTOR_DISABLED	Orange, Blue	Blinking, alternating
SENSOR_FAULT	Orange, Magenta	Blinking, alternating
DRIVER_FAULT	Orange, Cyan	Blinking, alternating
TRANSPORT_FAULT	Orange, Yellow	Blinking, alternating

Version

1.0

Date

2024-03-05

Copyright

Copyright (c) 2024

Defines

NUM_PIXELS

MAX_BRIGHTNESS

BLINK_PERIOD

IDENTIFY_TIMEOUT

Variables

Adafruit_NeoPixel strip

const uint32_t LED_OFF = strip.Color(0, 0, 0)

const uint32_t WHITE = strip.Color(255, 255, 255)

const uint32_t BLUE = strip.Color(0, 0, 255)

const uint32_t GREEN = strip.Color(0, 255, 0)

const uint32_t RED = strip.Color(255, 0, 0)

const uint32_t CYAN = strip.Color(0, 255, 255)

const uint32_t MAGENTA = strip.Color(255, 0, 255)

const uint32_t YELLOW = strip.Color(255, 255, 0)

const uint32_t ORANGE = strip.Color(255, 165, 0)

LEDStateMachine ledStateMachine

class LEDStateMachine : public StateMachine

Public Functions

inline LEDStateMachine(State &currentStatePtr)

Construct a new LEDStateMachine object.

Parameters:

currentStatePtr – Reference to the global currentState variable

void begin(void)

Initializes the NeoPixel LED and sets its brightness to MAX_BRIGHTNESS

virtual void executeState()

Executes various LED state tasks based on the current system state. This should be executed in a continuous loop as it needs constant updating. Any LED functions executed within should be asynchronous (non-blocking). If applicable, they should also be thread safe.

Private Functions

void setLEDColor(uint32_t color)

Sets the NeoPixel LED to the color.

Parameters:

color – Desired color to display on the LED.

void asyncBlink(uint32_t color, uint32_t interval = BLINK_PERIOD)

Asynchronously blinks the LED without blocking code execution (like when using delay())

Parameters:

• color – Desired color to display on the LED

• interval – Interval the LED stays ON and OFF

void asyncAlternatingBlink(uint32_t firstColor, uint32_t secondColor, uint32_t interval = BLINK_PERIOD)

Asynchronously alternates between two different LED colors.

Parameters:

• firstColor – The first desired color to display on the LED.

• secondColor – The second desired color to display on the LED.

• interval – The interval each color will be displayed before switching.