Controlling Robots using JavaScript. Slides from my talk at jsfoo. Details at http://sudarmuthu.com/blog/controlling-robots-using-javascript

1. Controlling robots
using JavaScript
Sudar Muthu (@sudarmuthu)
Research Engineer, Yahoo! Labs
http://hardwarefun.com
http://github.com/sudar

2. Who am I?
 Research Engineer by profession
 Creates robots as hobby
 Prefers Arduino
 Prefers JavaScript at work
 Why not combine both of them?
 .. and that’s what I am going to talk about today

3. Why hardware for a software hacker?
Fun!

4. Let’s start with a demo
Demo
http://hardwarefun.com/projects/asimijs

5. Participate in the demo 
Visit
http://hardwarefun.com:3000

6. Control the bot at stage
http://hardwarefun.com/projects/asimijs
#asimijs @hardwarefun

7. Arduino
 Visual Basic for hardware
 Includes both Hardware and software
Photo credit Arduino team

8. Interfacing Arduino with JavaScript
 Using serial connection (node-serialport)
 Using abstraction (like johnny-five or duino)
 Using serial Bluetooth connection (asimijs)

9. Using Serial Connection
You need node-serialport - https://github.com/voodootikigod/node-serialport
var SerialPort = require("serialport").SerialPort,
arduino = new SerialPort("/dev/tty/ACM1");
// when data is received from arduino
arduino.on("data", function (data) {
arduino.write(new Buffer[data]);
console.log("Got: " + data);
});
// if there was any error
arduino.on("error", function (data) {
console.log("Error: " + data);
});

10. Using Abstraction
 Build on top of node-serialport -
https://github.com/voodootikigod/node-serialport
 Options include Johnny-five -
https://github.com/rwldrn/johnny-five and duino -
https://github.com/ecto/duino
 Load the firmdata program into Arduino
 It provides the necessary abstraction
 Write code using a node.js library
 Profit 

11. Demo
Let there be LIGHT

12. Code
var five = require("johnny-five"),
board = new five.Board();
board.on("ready", function() {
// Create an Led on pin 13
(new five.Led(13)).strobe(1000);
});

13. Hardware setup

14. Reading sensor data
What you need?
Any sensor and a LED

15. Reading sensor data
var five = require("johnny-five"),
board, led, photoresistor;
board = new five.Board();
board.on("ready", function() {
// Create a new `photoresistor` hardware instance.
photoresistor = new five.Sensor({pin: "A2”, freq: 250});
led = new five.Led(13);
// "read" get the current reading from the photoresistor
photoresistor.on("read", function( err, value ) {
if (value > 50) {
led.on();
} else {
led.off();
}
console.log( value, this.normalized );
});
// Inject the `sensor` hardware into the Repl instance's context;
// allows direct command line access
board.repl.inject({
pot: photoresistor
});
});

16. Using serial Bluetooth connection
 Bluetooth shield gives wireless capability to Arduino
 A Bluetooth connection appears as serial port in your
computer
 Using node-serialport you can talk wirelessly to Arduino
 And that’s what I did for demo ;)

17. Using serial Bluetooth connection
var SerialPort = require("serialport").SerialPort,
bt = new SerialPort("/dev/cu.FireFly-CCFA-SPP");
// when data is received from bluetooth
bt.on("data", function (data) {
bt.write(new Buffer[data]);
console.log("Got: " + data);
});
// error reading bluetooth serial port
bt.on("error", function (data) {
console.log("Error: " + data);
});

18. How the demo worked
Node.js Server
Node Client
Admin page
User page
User page
User page

19. Links
 AsimiJS – The demo that I showed initially
http://hardwarefun.com/projects/asimijs
 Asimi – A simple bot using Arduino
http://hardwarefun.com/project/asimi
 Getting started with hardware programming
http://hardwarefun.com/tutorials/getting-started-with-
hardware-programming
 Getting started with Arduino
http://hardwarefun.com/tutorials/getting-started-with-arduino-
and-avr
 Node-serialport https://github.com/voodootikigod/node-
serialport
 Johnny Five https://github.com/rwldrn/johnny-five

20. Questions
Thank You
Sudar Muthu (@sudarmuthu)
http://hardwarefun.com
http://gitbub.com/sudar