85 lines
2.5 KiB
ReStructuredText
85 lines
2.5 KiB
ReStructuredText
Controlling NeoPixels
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=====================
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NeoPixels, also known as WS2812 LEDs, are full-colour LEDs that are connected in
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serial, are individually addressable, and can have their red, green and blue
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components set between 0 and 255. They require precise timing to control them
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and there is a special neopixel module to do just this.
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To create a NeoPixel object do the following::
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>>> import machine, neopixel
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>>> np = neopixel.NeoPixel(machine.Pin(4), 8)
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This configures a NeoPixel strip on GPIO4 with 8 pixels. You can adjust the
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"4" (pin number) and the "8" (number of pixel) to suit your set up.
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To set the colour of pixels use::
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>>> np[0] = (255, 0, 0) # set to red, full brightness
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>>> np[1] = (0, 128, 0) # set to green, half brightness
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>>> np[2] = (0, 0, 64) # set to blue, quarter brightness
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For LEDs with more than 3 colours, such as RGBW pixels or RGBY pixels, the
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NeoPixel class takes a ``bpp`` parameter. To setup a NeoPixel object for an
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RGBW Pixel, do the following::
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>>> import machine, neopixel
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>>> np = neopixel.NeoPixel(machine.Pin(4), 8, bpp=4)
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In a 4-bpp mode, remember to use 4-tuples instead of 3-tuples to set the colour.
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For example to set the first three pixels use::
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>>> np[0] = (255, 0, 0, 128) # Orange in an RGBY Setup
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>>> np[1] = (0, 255, 0, 128) # Yellow-green in an RGBY Setup
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>>> np[2] = (0, 0, 255, 128) # Green-blue in an RGBY Setup
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Then use the ``write()`` method to output the colours to the LEDs::
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>>> np.write()
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The following demo function makes a fancy show on the LEDs::
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import time
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def demo(np):
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n = np.n
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# cycle
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for i in range(4 * n):
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for j in range(n):
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np[j] = (0, 0, 0)
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np[i % n] = (255, 255, 255)
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np.write()
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time.sleep_ms(25)
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# bounce
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for i in range(4 * n):
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for j in range(n):
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np[j] = (0, 0, 128)
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if (i // n) % 2 == 0:
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np[i % n] = (0, 0, 0)
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else:
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np[n - 1 - (i % n)] = (0, 0, 0)
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np.write()
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time.sleep_ms(60)
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# fade in/out
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for i in range(0, 4 * 256, 8):
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for j in range(n):
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if (i // 256) % 2 == 0:
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val = i & 0xff
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else:
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val = 255 - (i & 0xff)
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np[j] = (val, 0, 0)
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np.write()
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# clear
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for i in range(n):
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np[i] = (0, 0, 0)
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np.write()
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Execute it using::
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>>> demo(np)
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