NeoPixel Chase

A basic NeoPixel example drives a 144-pixel WS2812B strip from GPIO16 with GPIO18 used as the strip power pin.

Behavior

• Powers the strip on at startup.

• Runs a simple blue chase across the LEDs.

• Leaves a short dim trail behind the moving pixel.

• Loops continuously with a steady frame rate.

Hardware

• Strip data: GPIO16

• Strip power: GPIO18

• Strip type: WS2812B NeoPixel-style LED strip

• Brightness: fixed at a moderate level

// Basic NeoPixel chase with strip power control.

var stripPin = 16;

var powerPin = 18; // xobit-circuit: IO18 ledStrip

var stripIndex = 0;

var ledCountValue = 50;

var baseBrightness = 50;

var chasePos = 0;

var lastFrameAt = 0;

var frameIntervalMs = 80;

function setup() {

  pinMode(powerPin, OUTPUT);

  digitalWrite(powerPin, HIGH);

  ledConfig(stripIndex, stripPin, ledCountValue, baseBrightness);

  ledClear(stripIndex, 1);

}

function loop() {

  var now = 0;

  var i = 0;

  now = millis();

  if ((now - lastFrameAt) < frameIntervalMs) {

    delay(10);

    return;

  }

  lastFrameAt = now;

  ledClear(stripIndex, 0);

  ledSet(stripIndex, chasePos, 0, 0, 255);

  i = chasePos - 1;

  if (i >= 0) {

    ledSet(stripIndex, i, 0, 0, 80);

  }

  i = chasePos - 2;

  if (i >= 0) {

    ledSet(stripIndex, i, 0, 0, 20);

  }

  ledShow();

  chasePos = chasePos + 1;

  if (chasePos >= ledCountValue) {

    chasePos = 0;

  }

  delay(5);

}

NeoPixel + BTN

NeoPixel Button 5

A NeoPixel strip uses GPIO16 for data and GPIO18 for power. A button on GPIO33 connects directly to ground and uses the internal pull-up.

Behavior

• Powers the strip on at startup.

• Reads the button on GPIO33 as active-low.

• Shows the first 15 pixels green when the button is released.

• Shows the first 15 pixels red while the button is pressed.

• Leaves the rest of the strip off.

Hardware

• Strip data: GPIO16

• Strip power: GPIO18

• Button input: GPIO13

• Strip type: WS2812B NeoPixel-style LED strip

• Active pixels: first 15 LEDs only

// Sets the first 15 NeoPixels green or red based on a button on GPIO33 wired directly to ground.

var stripPin = 16;

var powerPin = 18; // xobit-circuit: IO18 ledStrip

var buttonPin = 13; // xobit-circuit: IO33 button

var stripIndex = 0;

var ledCountValue = 15;

var baseBrightness = 50;

var buttonPressed = 0;

var i = 0;

function setup() {

  pinMode(powerPin, OUTPUT);

  digitalWrite(powerPin, HIGH);

  // Read the button.

  pinMode(buttonPin, INPUT_PULLUP);

  ledConfig(stripIndex, stripPin, ledCountValue, baseBrightness);

  ledClear(stripIndex, 1);

}

function loop() {

  // Read the button.

  buttonPressed = digitalRead(buttonPin) == LOW;

 //println(digitalRead(buttonPin) );

  ledClear(stripIndex, 0);

  i = 0;

  while (i < ledCountValue) {

    if (buttonPressed) {

      ledSet(stripIndex, i, 255, 0, 0);

    } else {

      ledSet(stripIndex, i, 0, 255, 0);

    }

    i = i + 1;

  }

  ledShow();

  delay(20);

}