WS2812B Addressable LED Control

Sylib provides an easy-to-use API for controlling WS2812B (Neopixel) LEDs

Hardware

To use these lights with a V5 brain, some custom wiring is needed. It is fairly simple, but some soldering is required.

I reccomend cutting up a VEX 3-wire extension cable in order to aquire a cable that can easily plug into the brain's ADI ports.

1) Solder the 5V (red/middle pin on the V5 ports) wire to the 5V line on your light strip 2) Solder the ground (black/bottom pin on the V5 ports) wire to the ground line on your light strip 3) Solder the data (white/top pin on the V5 ports) wire to the data line on your lights

Make sure to attach the wires to the correct side of the light strip, because they are directioned

Software

Full documentation can be found [here]

In order to control the lights, first create an Addrled object.

auto myLights = sylib::Addrled(1, 3, 64);

This creates an addressable led object configured as plugged into ADI port 3 (C) on an ADI expander plugged into smart port 1 that is 64 pixels long. 64 pixels is the maximum number that the V5 of this library supports.

In order to use the build-in three wire ports on the V5, use 22 as the smart port value.

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To set the entire strip to a certain color, use the set_all command

myLights.set_all(0xE62169);

This function takes an integer as an argument, and it is interpreted as a hexadecimal color code. The easiest way to use this is to supply a number already in hexadecimal form.

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In order to set the lights to a gradient of colors, use gradient

myLights.gradient(0x00FF00, 0x0000FF);

This starts the first pixel of the strip to #00FF00, and the last pixel to #0000FF, and uses linear interpolation in RGB color space to find values for the pixels in between.

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In order to set a single pixel to a certain color, use set_pixel

myLights.set_pixel(0x123456, 5);

This sets the 6th pixel on the strip to #123456

The pixel number is zero-indexed.

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To set every pixel at once, use set_buffer

auto colors = std::vector<std::uint32_t>();
colors.resize(16);
for(int i = 0; i < colors.size(); i++){
    colors[i] = sylib::Addrled::rgb_to_hex(64, 64, i * 15);
}
myLights.set_buffer(colors);

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To shift all colors by one pixel position, use rotate

myLights.rotate(1, false);

This shifts all colors down the strip by one pixel, in the positive direction, and loops the pixels at the end back around to the start.

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To continuously shift all colors down the strip, use cycle

myLights.cycle(*myLights, 15);

This sets the lights to what they were already at, then instructs sylib to automatically rotate the colors at a rate described by the speed parameter.

Instead of using what the lights were already at with *myLights, you can supply your own buffer, which can be larger than the maximum strip size.

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You can turn an individual light strip off with clear

myLights.clear();

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In order to send a single pulse of color down the strip, use pulse

myLights.pulse(0xF5A9B8, 2, 10);

This sends a pulse 2 pixels wide of color #F5A9B8 down the strip at speed 10.

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To shift the red, green, or blue values applied to the lights, use color_shift

myLights.color_shift(64, 0, -127);

This will make every pixel on the strip 64/255 more red, leave green unchanged, and make every pixel -127/255 less blue.

color_shift and pulse work on top of whatever other control is currently set for the lights. They do not modify the buffer stored by the Addrled object directly, only augment it before it is sent to the lights.