Intro deck for the Azure + Tessel hackathon

1. IoT Hackathon : Tessel
Thomas Conté @tomconte

2. The Tessel is tiny

3. Its modules too

4. Modules
▪ Accelerometer
▪ Ambient Light + Sound
▪ Audio
▪ Bluetooth Low Energy
▪ Camera
▪ Climate
▪ GPS
▪ GPRS
▪ Infrared
▪ MicroSD Card
▪ nRF24 Module
▪ Relay
▪ RFID
▪ Servo

6. http://blog.technical.io/post/98257815497/how-tessel-works-the-basics

7. What can you do with a Tessel?
▪ Ambient monitoring: monitor temperature, noise… Detect variations
and take action / notify.
– Is the light on at home?Turn on Hue lights automatically at dark.
▪ Accelerometer: game controllers, activity trackers…
▪ Camera: take pictures on event, motion detection…
▪ Infrared: control yourTV
– Clap your hands to turn it on
▪ Lots of projects ideas: https://projects.tessel.io/projects

8. What can you do with Azure?
▪ In theory, anything you can do in Node.JS
– In practice, some complex modules or projects will cause translation problems
because not all Node constructs are fully supported
– Most notably, the Azure SDKs for Node.JS seem to be causing some problems
– It might be easier to revert to plain old REST APIs when possible
▪ Upload stuff to Azure: Blob Storage
▪ Send monitoring/telemetry to Azure: Service Bus, Event Hubs
– Experiment with different protocols: HTTPS, AMQP, MQTT…
▪ Interact with mobile devices through Mobile Services
– Send notifications
▪ Labs on https://github.com/dx-ted-emea/azure-tessel

9. Node for Tessel crash course

10. Node.JS for the Tessel
▪ Node.JS is usually used on the server-side; here we are going to use it
on the client side!
▪ Node.JS is well suited to real-time processing of events, thanks to its
asynchronous nature; this is well adapted to a device whose main job
is to monitor and process events (temperature / noise / light / etc.)
▪ Instead of listening to server-side events (GET, POST, etc.) you will be
listening to module-specific events
▪ Events are handled using callbacks, functions that you pass when
registering for the event

11. Hello World: tessel run blinky.js
// Import the interface to Tessel hardware
var tessel = require('tessel');
// Set the led pins as outputs with initial states
// Truthy initial state sets the pin high
// Falsy sets it low.
var led1 = tessel.led[0].output(1);
var led2 = tessel.led[1].output(0);
setInterval(function () {
console.log("I'm blinking! (Press CTRL + C to stop)");
// Toggle the led states
led1.toggle();
led2.toggle();
}, 100);

12. npm for the Tessel
▪ When you install theTessel library, you will use npm –g
▪ This will install the library and CLI “globally”, i.e. in a place where it
can be found by default from your shell
▪ When you installTessel Node.JS modules (corresponding to the
hardware “modules”) you will not use –g
▪ This will install the module locally in a directory called node_modules
▪ When you run your script with tessel run, all the dependent modules
in node_modules will automatically be packaged and sent to the
Tessel

13. Listen for Ambient module events
var tessel = require('tessel');
var ambientlib = require('ambient-attx4');
var ambient = ambientlib.use(tessel.port['A']);
ambient.on('ready', function () {
ambient.setLightTrigger(0.5);
ambient.on('light-trigger', function(data) {
console.log("Our light trigger was hit:", data);
});
});

14. JavaScript callback hell
var db = require('somedatabaseprovider');
http.get('/recentposts', function(req, res){
db.openConnection('host', creds, function(err, conn){
res.param['posts'].forEach(post) {
conn.query('select * from users where id=' + post['user'],function(err,results){
conn.close();
res.send(results[0]);
});
}
});
});

15. Don’t panic
var db = require('somedatabaseprovider');
http.get('/recentposts', afterRecentPosts);
function afterRecentPosts(req, res) {
db.openConnection('host', creds, function(err, conn) {
afterDBConnected(res, conn);
});
}
function afterDBConnected(err, conn) {
res.param['posts'].forEach(post) {
conn.query('select * from users where id=‘
+post['user'],afterQuery);
}
}
function afterQuery(err, results) {
conn.close();
res.send(results[0]);
}
▪ Avoid anonymous callbacks
▪ Give them names and move
them out of the “pyramid”
▪ This is good enough to
make the code reasonably
maintainable
▪ To go further, explore
JavaScript Promises and/or
the Q library

16. Let’s hack!
▪ Grab your hardware
▪ Pair up
–Might be best to have one person who knows
JS/Node per pair
▪ Get something done in 4 hours
▪ Present your results/learnings/findings

17. Getting Started
▪ First, install Node.JS!
–http://nodejs.org/
–Click on the big green INSTALL button
▪ Go to tessel.io/start
▪ Basically,
–npm install -g tessel
–tessel update

18. More getting started: Wi-Fi
▪ Pretty hard to connect to MSFT network, even MSFTOPEN isn’t
stable
▪ Revert to using phone hotspot
▪ tessel wifi -n “MyPhone" -p "Passxyz "

19. The End