index.js

var arduino = require("johnny-five")
  , board = new arduino.Board()
  , photo = require('./photo')
  , SendGrid = require('sendgrid').SendGrid
  , sg = new SendGrid(process.env.SENDGRID_USER, process.env.SENDGRID_PASS);

board.on("ready", function() {
  var button = new arduino.Button(3);

  button.on("up", function() {
    photo(function(err, html) {
      sg.send({
        to: "[email protected]",
        from: "[email protected]",
        subject: "Stop tweeting!",
        html: html
      }, function() {
        console.log(arguments);
      });
    });
  });
});

package.json

{
  "name": "swift_sendgrid_demo_3",
  "version": "0.0.1",
  "description": "Arduino powered SendGridness.",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "repository": "",
  "keywords": [
    "SendGrid",
    "Arduino"
  ],
  "author": "Swift <[email protected]>",
  "license": "Beerware",
  "dependencies": {
    "sendgrid": "~0.2.4",
    "johnny-five": "~0.5.14",
    "request": "~2.12.0"
  }
}

photo.js

module.exports = function getImage(cb) {
  var request = require('request')
    , callback = cb || function() {}
    , tumblr_key = process.env.TUMBLR_KEY
    , post = Math.floor((Math.random()*96))
    , url = "http://api.tumblr.com/v2/blog/programmerryangosling.tumblr.com/posts?api_key=" + tumblr_key + "&type=photo&limit=1&offset=" + post;

  request(url, function(err, res, body) {
    try {
      var image = JSON.parse(body).response.posts[0].photos[0].original_size.url;
      callback(err, "<img src='" + image + "' width='50%' />");
    } catch(e) {
      callback(e);
    }
  });
};