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LED Strip Module - Library Reference

This is the library reference for the LED Strip Module for Yukon.

Getting Started

To start using a LED Strip Module, you first need to import the class from pimoroni_yukon.modules.

from pimoroni_yukon.modules import LEDStripModule

Then create an instance of LEDStripModule, giving it details of the LEDs you wish to drive, and which PIO and State Machine (SM) to use.

# Constants
STRIP_TYPE = LEDStripModule.NEOPIXEL
STRIP_PIO = 0
STRIP_SM = 0
LEDS_PER_STRIP = 60
BRIGHTNESS = 1.0        # Only functional with APA102 (DOTSTAR)

module = LEDStripModule(STRIP_TYPE,
                        STRIP_PIO,
                        STRIP_SM, 
                        LEDS_PER_STRIP,
                        BRIGHTNESS)

⚠️ Be sure to choose a PIO and State Machine that does not conflict with any others you have already set up.

Strip Types

Both WS2812's (aka NeoPixels) and APA102's (aka DotStars) are supported by the LEDStripModule.

There is also a third mode, where two WS2812 strips can be driven off the one module, by wiring one to the DAT line as normal, and the other to the CLK line.

Strip types can accessed with the following constants:

  • LEDStripModule.NEOPIXEL = 0
  • LEDStripModule.DUAL_NEOPIXEL = 1
  • LEDStripModule.DOTSTAR = 2

When using the DUAL_NEOPIXEL strip type, the lengths of the two strips can be provided as a tuple pair as the LEDS_PER_STRIP constant from the getting started section, or left as a single value if both strips are the same length.

Initialising the Module

As with all Yukon modules, LEDStripModule must be initialised before it can be used. This is achieved by first registering the module with the Yukon class, with the slot it is attached to.

from pimoroni_yukon import SLOT1 as SLOT

# Import and set up Yukon and LEDStripModule instances

yukon.register_with_slot(module, SLOT)

Then Yukon can verify and initialise its modules.

yukon.verify_and_initialise()

This checks each slot on the board to see if the modules expected by your program are physically attached to the board. Only if they match will the LEDStripModule be initialised, giving it access to the GPIO of the slot it is attached to.

Power can now be provided to all modules, by calling.

yukon.enable_main_output()

Using the Module

Enabling its Output

With the LEDStripModule powered, its output to the strip(s) can be enabled or disabled by calling .enable() or .disable(). The state can also be queried by calling .is_enabled().

Accessing the LED Strip

The LEDStripModule class makes use of the Plasma Library. Depending on the strip type provided during creation, either an APA102 objects or WS2812 objects will be accessible through the variable .strip.

For example, to set all the LEDs of the strip to full (for either APA102 or WS2812), the following loop can be run:

for led in range(module.strip.num_leds()):
    module.strip.set_rgb(led, 255, 255, 255)

module.strip.update()

For the case of the DUAL_NEOPIXEL strip type, a .strips list is accessible containing two WS2812 objects, instead of a .strip variable. There are also .strip1 and .strip2 properties to make access to these strips easier.

Onboard Sensors

The LED Strip module features an onboard thermistor, letting its temperature be monitored. This can be read by calling .read_temperature().

Additionally, the power good status of the onboard regulator can be read by calling .read_power_good(). This will be True during normal operation, but will switch to False under various conditions such as the input voltage dropping below what is needed for the module to achieve a stable output. For details of other conditions, check the TPS54A24 datasheet.

Reference

Constants

NAME = "LED Strip"
NEOPIXEL = 0
DUAL_NEOPIXEL = 1
DOTSTAR = 2
STRIP_1 = 0       # Only for DUAL_NEOPIXEL strip_type
STRIP_2 = 1       # Only for DUAL_NEOPIXEL strip_type
NUM_STRIPS = 1    # Becomes 2 with the DUAL_NEOPIXEL strip_type
TEMPERATURE_THRESHOLD = 80.0

Variables

halt_on_not_pgood: bool

# If strip_type is NEOPIXEL or DOTSTAR
strip: APA102 | WS2812

# If strip_type is DUAL_NEOPIXEL
strips: list[WS2812]

Functions

# Address Checking
@staticmethod
is_module(adc1_level: int, adc2_level: int, slow1: bool, slow2: bool, slow3: bool) -> bool

# Initialisation
LEDStripModule(strip_type: int,
               pio: int,
               sm: int,
               num_leds: int,
               brightness: float=1.0,
               halt_on_not_pgood: bool=False)
initialise(slot: SLOT, adc1_func: Callable, adc2_func: Callable) -> None
reset() -> None

# Power Control
enable() -> None
disable() -> None
is_enabled() -> bool

# Access (only usable when strip_type is DUAL_NEOPIXEL)
@property
strip1 -> WS2812
@property
strip2 -> WS2812

# Sensing
read_power_good() -> bool
read_temperature(samples: int=1) -> float

# Monitoring
monitor() -> None
get_readings() -> OrderedDict
process_readings() -> None
clear_readings() -> None