Demonstrates use of callbacks to fade out a series of LEDs one after the other. Requires LEDs on pins that support PWM (usually denoted by ~).
Fritzing diagram: docs/breadboard/led-fade-callback.fzz
Run this example from the command line with:
node eg/led-fade-callback.js
const {Board, Leds} = require("johnny-five");
const board = new Board();
board.on("ready", () => {
// Set up the following PWM pins as LEDs.
// Fade an LED out, and the complete callback will start
// fading the next LED in sequence out, and so on.
// If randomFade is true, then fading will happen in random
// order instead of sequentially.
const leds = new Leds([11, 10, 9, 6, 5, 3]);
const timing = 250;
const randomFade = true;
const ledCount = leds.length;
let fadeIndex = 0;
function fadeNext() {
let candidateIndex = fadeIndex;
leds[fadeIndex].fadeIn(timing);
// Determine the next LED to fade
if (randomFade) {
while (candidateIndex === fadeIndex) {
candidateIndex = Math.round(Math.random() * (ledCount - 1));
}
} else {
candidateIndex = (fadeIndex < ledCount - 1) ? fadeIndex + 1 : 0;
}
fadeIndex = candidateIndex;
leds[fadeIndex].fadeOut(timing, fadeNext);
}
leds.on();
leds[fadeIndex].fadeOut(timing, fadeNext);
});
Copyright (c) 2012-2014 Rick Waldron waldron.rick@gmail.com Licensed under the MIT license. Copyright (c) 2015-2023 The Johnny-Five Contributors Licensed under the MIT license.