Flow LEDs

In this kit is equipped with a WS2812 RGB 8 LEDs Strip, which can display colorful colors and each LED can be controlled independently.

Here, a tilt switch is used to control the flow direction of LED on the WS2812 Strip.






After the code runs, when the tilt switch is placed vertically, the LED on the WS2812 Strip will light up from one side, and when it is placed horizontally, the WS2812 will light up from the other side.

How it works?

#include <Adafruit_NeoPixel.h>

Adafruit_NeoPixel pixels(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);

Import the Adafruit_NeoPixel.h library and create a object pixel to control WS2812. The three parameters NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800 are used to declare the number of LED pixels, pin number and Pixel type flags.


To use this library, open the Library Manager in the Arduino IDE and install it from there.

Sketch -> Include Library -> Manager Libraries


This statement is used to initialize the NeoPixel strip object.

if (ledIndex < 0) {
  ledIndex = NUMPIXELS-1;
else if (ledIndex >= NUMPIXELS) {
  ledIndex = 0;

Limit the value of ledIndex to 0 to NUMPIXELS. When it is greater than this range, ledIndex is re-assigned to 0. When it is less than this range, ledIndex is re-assigned to NUMPIXELS-1.


This statement set pixel colors to 0 (off).

pixels.setPixelColor(ledIndex, pixels.Color(100, 50, 0))

This statement is used to set the color of the WS2812 Strip, the first parameter refers to the serial number of the WS2812 Strip, and the second parameter represents the color.


Show the effect on WS2812 Strip.