PPTX - Intel Software Academic Program
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Internet of Things with Intel Edison
Web controller
Pierre Collet
www.Intel-Software-Academic-Program.com
paul.guermonprez@intel.com
Intel Software
2014-10-14
Objectives
Objective
Edison is highly connected, so let’s use the network :
Edison as a web server, your laptop as a network client.
We’ll interact with a LED, because that’s a thing you could not do on a regular PC.
NodeJS
We’ll use NodeJS : it’s a JavaScript based framework,
but commonly used from a command line interpreter, not in a browser window.
NodeJS is also asynchronous / functional programming,
making it very easy to develop network interactions.
It’s very popular in the IoT field, and there’s tons of libraries in NodeJS.
What do you need?
Software
On Windows, we use Putty as ssh client.
http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html
On mac or linux, ssh is part of the regular shell.
We’ll run NodeJS framework on the Edison board itself, as a server
language. But you can also install NodeJS on your laptop to run some
scripts locally.
Run script
The code discussed today is available from the folder :
labs/nodeserver.
To execute the script, run :
node ./webcontroller.js
Web LED controller demo
Architecture
Architecture – Network side
NodeJS will create html and send it over the network.
Your browser will display the result.
Architecture – LED side
NodeJS will launch 2 scripts to control the LED : onLed.sh and offLed.sh
They are controlling the pin 7.
Architecture – NodeJS library or System call ?
In the future, you may find a NodeJS modules to interface sensors on Edison and you
won’t need to call shell scripts. We already have galileo-io for Intel Galileo.
But it’s good to know you don’t need a native NodeJS module for simple things.
It’s important for other scripting languages where no Edison module will come :
remember you can call libmraa binaries or shell scripts.
The Code
# Import child_process function
var system = require(‘child_process’).exec;
# TurnOnLed function
function turnOnLed(){
system(‘sh ./onLed.sh’); /* execute the shell script */
ledstatus = “on”;
}
# A simple HTTP server
var http = require('http');
http.createServer(function (req, res) {
function respond() {
res.writeHead(200, { "Content-Type": "text/html" });
res.end(“Hello World");
}).listen(1337);
The Code
# A function to send the default home page
function respond() {
res.writeHead(200, { "Content-Type": "text/html" });
res.write("<!DOCTYPE html><html><body>");
res.write("<h1>Intel Edison web controller</h1>");
res.write("<p>Sensor value : ");
res.write(sensorvalue);
res.write("</p><p>LED Status : ");
res.write(ledstatus);
res.write("</p><p>Action</p>");
res.write("<p><input type='button' onclick='location.reload();' value='Refresh'/></p>");
res.write("<p><input type='button' onclick=‘location.pathname =
\"/ledOn\"' value='Turn LED on'/></p>");
res.write("<p><input type='button' onclick=‘location.pathname =
\"/ledOff\"' value='Turn LED off'/></p>");
res.write("</body></html>");
res.end();
}
The Code
Analyzing URL to determine the command
console.log("Request: " + req.url);
if(req.url === "/ledOn")
turnOnLed();
else if(req.url === "/ledOff")
turnOffLed();
respond();
}).listen(1337);
console.log('Server running at http://localhost:1337/');
}
Running the server
startServer();
Demo
Open your browser
Access the URL : http://192.168.XXX.XXX:1337/
Click on buttons to test your implementation!
Conclusion
Network – Object
With this demo, we’ve seen we can interact with an IoT object (LED, sensor) on one
side and the network on the other side. That’s the definition of an IoT.
Full Server
Edison is not only sending data over the network. It can act as a server.
We used NodeJS, but larger stacks like Apache or JBoss run very well.
NodeJS
NodeJS is a great framework for networked IoT. Even if there’s no module to do what
you need, just call a script or a libmraa binary !
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