import atexit
try:
import RPi.GPIO as GPIO
except ImportError:
raise ImportError("This library requires the RPi.GPIO module\nInstall with: sudo pip install RPi.GPIO")
DAT = 10
CLK = 11
CS = 8
NUM_PIXELS = 7
BRIGHTNESS = 7
pixels = [[0,0,0,BRIGHTNESS]] * NUM_PIXELS
_gpio_setup = False
_clear_on_exit = True
def _exit():
if _clear_on_exit:
clear()
show()
GPIO.cleanup()
def set_brightness(brightness):
"""Set the brightness of all pixels
:param brightness: Brightness: 0.0 to 1.0
"""
if brightness < 0 or brightness > 1:
raise ValueError("Brightness should be between 0.0 and 1.0")
for x in range(NUM_PIXELS):
pixels[x][3] = int(31.0 * brightness) & 0b11111
def clear():
"""Clear the pixel buffer"""
for x in range(NUM_PIXELS):
pixels[x][0:3] = [0,0,0]
def _write_byte(byte):
for x in range(8):
GPIO.output(DAT, byte & 0b10000000)
GPIO.output(CLK, 1)
byte <<= 1
GPIO.output(CLK, 0)
# Emit exactly enough clock pulses to latch the small dark die APA102s which are weird
# for some reason it takes 36 clocks, the other IC takes just 4 (number of pixels/2)
def _eof():
GPIO.output(DAT, 0)
for x in range(36):
GPIO.output(CLK, 1)
GPIO.output(CLK, 0)
def _sof():
GPIO.output(DAT,0)
for x in range(32):
GPIO.output(CLK, 1)
GPIO.output(CLK, 0)
def show():
"""Output the buffer"""
global _gpio_setup
if not _gpio_setup:
GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
GPIO.setup([DAT,CLK,CS],GPIO.OUT)
_gpio_setup = True
GPIO.output(CS, 0)
_sof()
for pixel in pixels:
r, g, b, brightness = pixel
_write_byte(0b11100000 | brightness)
_write_byte(b)
_write_byte(g)
_write_byte(r)
_eof()
GPIO.output(CS, 1)
def set_all(r, g, b, brightness=None):
"""Set the RGB value and optionally brightness of all pixels
If you don't supply a brightness value, the last value set for each pixel be kept.
:param r: Amount of red: 0 to 255
:param g: Amount of green: 0 to 255
:param b: Amount of blue: 0 to 255
:param brightness: Brightness: 0.0 to 1.0 (default around 0.2)
"""
for x in range(NUM_PIXELS):
set_pixel(x, r, g, b, brightness)
def set_pixel(x, r, g, b, brightness=None):
"""Set the RGB value, and optionally brightness, of a single pixel
If you don't supply a brightness value, the last value will be kept.
:param x: The horizontal position of the pixel: 0 to 7
:param r: Amount of red: 0 to 255
:param g: Amount of green: 0 to 255
:param b: Amount of blue: 0 to 255
:param brightness: Brightness: 0.0 to 1.0 (default around 0.2)
"""
if x >= NUM_PIXELS:
raise ValueError("Invalid pixel index {}, should be (0-{})".format(x, NUM_PIXELS-1))
if brightness is None:
brightness = pixels[x][3]
else:
brightness = int(31.0 * brightness) & 0b11111
pixels[x] = [int(r) & 0xff,int(g) & 0xff,int(b) & 0xff,brightness]
def set_clear_on_exit(value=True):
"""Set whether the APA102 should be cleared upon exit
By default the APA102 will turn off the pixels on exit, but calling::
set_clear_on_exit(False)
Will ensure that it does not.
:param value: True or False (default True)
"""
global _clear_on_exit
_clear_on_exit = value
atexit.register(_exit)