92 lines
3.2 KiB
ReStructuredText
92 lines
3.2 KiB
ReStructuredText
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Controlling APA102 LEDs
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=======================
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APA102 LEDs, also known as DotStar LEDs, are individually addressable
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full-colour RGB LEDs, generally in a string formation. They differ from
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NeoPixels in that they require two pins to control - both a Clock and Data pin.
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They can operate at a much higher data and PWM frequencies than NeoPixels and
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are more suitable for persistence-of-vision effects.
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To create an APA102 object do the following::
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>>> import machine, apa102
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>>> strip = apa102.APA102(machine.Pin(5), machine.Pin(4), 60)
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This configures an 60 pixel APA102 strip with clock on GPIO5 and data on GPIO4.
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You can adjust the pin numbers and the number of pixels to suit your needs.
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The RGB colour data, as well as a brightness level, is sent to the APA102 in a
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certain order. Usually this is ``(Red, Green, Blue, Brightness)``.
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If you are using one of the newer APA102C LEDs the green and blue are swapped,
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so the order is ``(Red, Blue, Green, Brightness)``.
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The APA102 has more of a square lens while the APA102C has more of a round one.
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If you are using a APA102C strip and would prefer to provide colours in RGB
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order instead of RBG, you can customise the tuple colour order like so::
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>>> strip.ORDER = (0, 2, 1, 3)
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To set the colour of pixels use::
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>>> strip[0] = (255, 255, 255, 31) # set to white, full brightness
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>>> strip[1] = (255, 0, 0, 31) # set to red, full brightness
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>>> strip[2] = (0, 255, 0, 15) # set to green, half brightness
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>>> strip[3] = (0, 0, 255, 7) # set to blue, quarter brightness
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Use the ``write()`` method to output the colours to the LEDs::
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>>> strip.write()
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Demonstration::
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import time
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import machine, apa102
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# 1M strip with 60 LEDs
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strip = apa102.APA102(machine.Pin(5), machine.Pin(4), 60)
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brightness = 1 # 0 is off, 1 is dim, 31 is max
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# Helper for converting 0-255 offset to a colour tuple
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def wheel(offset, brightness):
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# The colours are a transition r - g - b - back to r
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offset = 255 - offset
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if offset < 85:
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return (255 - offset * 3, 0, offset * 3, brightness)
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if offset < 170:
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offset -= 85
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return (0, offset * 3, 255 - offset * 3, brightness)
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offset -= 170
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return (offset * 3, 255 - offset * 3, 0, brightness)
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# Demo 1: RGB RGB RGB
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red = 0xff0000
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green = red >> 8
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blue = red >> 16
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for i in range(strip.n):
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colour = red >> (i % 3) * 8
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strip[i] = ((colour & red) >> 16, (colour & green) >> 8, (colour & blue), brightness)
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strip.write()
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# Demo 2: Show all colours of the rainbow
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for i in range(strip.n):
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strip[i] = wheel((i * 256 // strip.n) % 255, brightness)
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strip.write()
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# Demo 3: Fade all pixels together through rainbow colours, offset each pixel
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for r in range(5):
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for n in range(256):
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for i in range(strip.n):
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strip[i] = wheel(((i * 256 // strip.n) + n) & 255, brightness)
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strip.write()
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time.sleep_ms(25)
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# Demo 4: Same colour, different brightness levels
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for b in range(31,-1,-1):
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strip[0] = (255, 153, 0, b)
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strip.write()
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time.sleep_ms(250)
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# End: Turn off all the LEDs
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strip.fill((0, 0, 0, 0))
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strip.write()
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