"use strict"; var Cylon = require("cylon"); Cylon .robot() .connection("arduino", { adaptor: "firmata", port: "/dev/ttyACM0" }) .device("led", { driver: "led", pin: 3 }) .on("ready", function(bot) { var brightness = 0, fade = 5; setInterval(function() { brightness += fade; bot.led.brightness(brightness); if ((brightness === 0) || (brightness === 255)) { fade = -fade; } }, 500); }); Cylon.start();