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Blinky

In this lab, we're going to connect to the device with Johnny-Five and start sending the device commands.

There is a standard "Hello World" with the Arduino and it's a blinking LED. We're going to do that first because it doesn't actually require any wiring but you can plug an LED in if you want to. It's optional because the LED pin we are going to use is wired to a light that is hard wired on the board as well as a pin in the pinout section.

Setting up your NPM prerequisites

Node uses a install manager called the Node Package Manager (NPM) to install anything that you are dependent on in your node.js application. You can either manually run npm for each package or you can create a package.json file and install with a single command.

  1. Create a file called package.json
    {
      "name": "n2labs",
      "homepage": "<some url>",
      "author": "<your name>",
      "licenses": [
        {
          "type": "<Your license>",
          "url": "<Your license URL>"
        }
      ],
      "main": "./lib",
      "repository": {
        "type": "git",
        "url": "<your git repo>"
      },
      "version": "0.0.1",
      "dependencies": {
        "johnny-five": "~0.8.37"
      },
      "keywords": [
        "devices",
        "iot",
        "arduino",
        "yun",
        "arduino yun"
      ]
    }

  1. Run the npm install

    npm install

Let's get coding:

The next thing to do is to set up the device in JavaScript and start talking to it.

  1. Create a file called blinky.js.
  2. Type in your requires. The things that are listed here are the things that this file has access to. This should match what's in your package.json file.
    var five = require("johnny-five");

  1. Now let's fill out your board initialization

    Please refer to the Running Johnny-Five to make sure you are connecting properly for your platform.

        var board = new five.Board();

        var LEDPIN = 13; //13 is an LED on the board as well as a pin

        board.on("ready", function(){
            console.log("Board connected...");

            this.pinMode(LEDPIN, five.Pin.OUTPUT);
            var led = new five.Pin(LEDPIN);

            led.write(1);
        });

Running your device

At this point you can run the app and start your device. The Johnny-Five app will connect to the standard firmata that's on the device and start sending it commands.

  1. Run your device with the following command

    node blinky.js

Summary

In this lab you've gotten your first device up and running and are turning on the light.

Extra credit.

Modify the board.on section to loop rather than just turn on the light.

board.on("ready", function(){
  console.log("Board connected...");

  this.pinMode(LEDPIN, five.Pin.OUTPUT);
  var led = new five.Pin(LEDPIN);

  var pinOn = false;
    setInterval(function() {
        if (pinOn)
        {
            console.log("Pin off");
            led.write(0);
        }
        else
        {
            console.log("Pin on");
            led.write(1);
        }
        pinOn = !pinOn;
    }, 1000);
});

Extra extra credit - hook up an LED between pin 13 on your board and the ground so that you can see separate LED turn on.

Wrap up

At this point you should have a high level understanding of Johnny-Five and be ready to start receiving data from the device.

next lab - light sensor