Interface javascript with arduino

Question

I'm an arduino noob and I'm trying to interface some javascript with arduino. For now all I'm trying to do is move a servomotor in a direction if a js variable is under a certain value and moving it the other way if it's above that value. I don't have a clue about how i should tackle this, so I'd appreciate any help. I do have the servomotor moving part and the javascript part, I just don't know how to put them together.

Answer 1

For now all I'm trying to do is move a servomotor in a direction if a js variable is under a certain value and moving it the other way if it's above that value.

Here's how you can accomplish this with Johnny-Five:

1. Make sure you have node and npm installed
2. With the Arduino IDE, upload StandardFirmata (File -> Examples -> Firmata -> StandardFirmata) to the Arduino, close the IDE
3. npm install johnny-five
4. create a new JS file, save the following in it:

var five = require("johnny-five");
var board = new five.Board();

board.on("ready", function() {

  var servo = new five.Servo(11);

  this.repl.inject({
    move: function(value) {
      var angle = 0;
      if (value > 0) {
        angle = 180;
      }
      servo.to(angle);
    }
  });
});

4. With the USB cable plugged in to the board and computer, run the above program in your terminal. Once it's running, call move(n) where n is any number. Numbers greater than 0 will move the servo to 180°; numbers less than or equal to 0 will move the servo to 0°.