The 12mm LED pixels are really easy to use with CircuitPython and the Adafruit CircuitPython WS2801 module.
Initialization
Whether you connected the LED Pixels to your microcontroller through the Hardware SPI or Software SPI, initialization is about the same.
import board import adafruit_ws2801 odata = board.D5 oclock = board.D6 numleds = 25 bright = 1.0 leds = adafruit_ws2801.WS2801(oclock, odata, numleds, brightness=bright, auto_write=False)
In this example, we are using D5 and D6, which are for driving it through software. If we were driving it through hardware on the Raspberry Pi, we would use the following Pins:
odata = board.MOSI oclock = board.SCK
Make sure the number of LEDs corresponds to the actual number that you had. For instance, if you had two strands of 25 LEDs, that's 50 LEDs.
You can adjust the brightness by changing the number between 0 and 1.0. Setting it lower than one requires a little more processor power because to achieve that effect, they need to rapidly turned on and off.
If you didn't want to have to call show() in order to update the strand, you could either set auto_write to True or remove it from the initializer altogether.
Showing Changes
If auto_write is set to False, you will need to call show() in order to show any changes you made to the lights:
leds[0] = 0xff0000 leds.show()
Filling All Lights At Once
You can fill all the lights at once with the fill command. The color can either be a tuple of Red, Green, and Blue as a number between 0-255 each, a hexadecimal number in the format of 0xRRGGBB:
# Use an RGB Tuple leds.fill((255, 0, 0)) # Use a Hexidecimal Value leds.fill(0xff0000)
Setting an individual LED
You can set the value of a single LED by passing a color value as a tuple or hexadecimal value to an index:
leds[0] = (0, 0, 255) # Set the first LED blue leds[1] = 0x00ff00 # Set the second LED Green
Setting Multiple Values
You can set multiple values at the same time using a slice. For instance, if you wanted to set the first three LEDs to Red, Green, and Blue, you could type the following:
leds[0:3] = ((255, 0, 0),
(0, 255, 0),
(0, 0, 255))
Getting a Value
Just like you can set the LEDs, you can also read the current value of the LEDs. The value will be returned as a Tuple:
leds[0] = 0xff0000 leds[1] = 0x00ff00 leds[2] = 0x0000ff my_color = leds[0] # Returns (255, 0, 0) my_colors = leds[0:3] # Returns [(255, 0, 0), (0, 255, 0), (0, 0, 255)]
Setting the Brightness
You can change the brightness of all the lights by changing the brightness property and setting it between 0 and 1.0:
leds.brightness = 0.5 # Set to 50% Brightness
With just this handful of commands, you can do some cool effects and animations. Having the auto_write set to False makes adding cool effects even easier because you can change each light and then call show() to make all changes visible at once. You could do some cool animations this way. You could even get values and set other values up the chain for a shifting lights effect.
# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT
### Based on example from
### https://github.com/adafruit/Adafruit_CircuitPython_DotStar/tree/master/examples
import time
import random
import board
import adafruit_ws2801
### Example for a Feather M4 driving 25 12mm leds
odata = board.D5
oclock = board.D6
numleds = 25
bright = 1.0
leds = adafruit_ws2801.WS2801(
oclock, odata, numleds, brightness=bright, auto_write=False
)
######################### HELPERS ##############################
# a random color 0 -> 224
def random_color():
return random.randrange(0, 7) * 32
######################### MAIN LOOP ##############################
n_leds = len(leds)
while True:
# fill each led with a random color
for idx in range(n_leds):
leds[idx] = (random_color(), random_color(), random_color())
# show all leds in led string
leds.show()
time.sleep(0.25)
