firmata-electron/examples/servo-config.js

A library to control an arduino running firmata

var Board = require("../lib/firmata").Board;
var board = new Board("/dev/tty.usbmodem1421");

board.on("ready", function() {
  var degrees = 10;
  var incrementer = 10;

  // This will map 0-180 to 1000-1500
  board.servoConfig(9, 1000, 1500);
  board.servoWrite(9, 0);

  setInterval(function() {
    if (degrees >= 180 || degrees === 0) {
      incrementer *= -1;
    }
    degrees += incrementer;
    board.servoWrite(9, degrees);
    console.log(degrees);
  }, 500);
});