This document discusses building a home automation system completely with JavaScript. It describes using a BeagleBone Black microcontroller board with BoneScript to control pins and switch currents on and off. A REST API built with Node.js is proposed to allow controlling devices from any client. An AngularJS frontend could then be used to build a responsive user interface for mobile or web. The system allows controlling devices remotely over WiFi from a web or mobile app.

1. Home Automation
Done completely with Javascript

2. The Basics
Components
1.A controller/driver (Power Electronic Switch)
2.Logic circuit for controller/driver
3.Software interface for logic circuit
4.Server-Client, or Socket based model (the API)
5.User Interface

3. What we will use
Controller : BeagleBone Black
A microcomputer board (like Raspberry Pi), with multiple
pinouts, running on an ARM processor. Regular Debian/Ubuntu
Linux OS.
Language (HW control): BoneScript
A Node.js plugin developed especially for boards like BBB
which provides a JS interface to turn current to the pins of a BBB
on or off (or read the current for input PINS). BoneScript is
similar to the Arduino language.

4. What we will use
Language (API) : Socket.io or Node.js REST
If we directly access a webpage hosted on the BBB, we can use
socket.io, or we can create a RESTful API on the BBB.
Language (UI): AngularJS
We can use any MVC or pure JS too. This is the frontend for
the given REST API on the BBB to control the states of the
switches.

5. How switching works

Power Electronics – Controlling Electrical
appliances with Electronics

Common switches - BJT, MOSFET, TRIAC,
DIAC

A 5V-1A cirtuit can control a 220V-15A circuit.

6. How switching works

7. BoneScript
Setting a PIN output to high current
var b = require('bonescript');
b.pinMode('USR0', b.OUTPUT);
b.digitalWrite('USR0', b.HIGH);

8. BoneScript
Read input current from a PIN
var b = require('bonescript');
b.pinMode('P8_19', b.INPUT);
b.digitalRead('P8_19', printStatus);
function printStatus(x) {
console.log('x.value = ' + x.value);
console.log('x.err = ' + x.err);
}

9. BoneScript
Blink a LED
var b = require('bonescript');
var led = "USR3";
var state = 0;
b.pinMode(led, 'out');
toggleLED = function() {
state = state ? 0 : 1;
b.digitalWrite(led, state);
};
timer = setInterval(toggleLED, 100);
stopTimer = function() {
clearInterval(timer);
};
setTimeout(stopTimer, 3000);

10. Basic home automation with Bonescript
Connect LEDs on some of the PINS of the BBB
Create a webpage on the BBB
Make buttons on the page. Each button calls a digitalWrite function
corresponding to connected LEDs.
On page load read PIN states and updates button accordingly. Red
color for off, Green for on (or something similar).
Connect the BBB to WLAN/Internet.
Access IP of BBB from Laptop/Mobile, click the buttons and watch the
LEDs go ON and OFF.
*** Make a video, or show live demo of this if WiFi available ***

11. Why this isn’t practically applicable ?
HAVE TO open the particular webpage on the particular
IP. Who remembers URLs and IPs ?
No App for mobile, have to do via browser.
Clients cannot be built for devices that do not have JS
support.

12. Solution : REST Api
We will create a simple REST API using Node.js
and Express 4.
var express = require('express');
var app = express();
app.get('/switch/fan/:state', function(req, res) {
if (req.params.state === 1)
// digitalWrite high to the required PIN
else
// digitalWrite low to the required PIN
});
app.listen(8080);

13. Solution : REST Api
We make REST calls from the client to turn the
fan off or on
http://bbb.ip/switch/fan/0 -- **to turn off the fan**
http://bbb.ip/switch/fan/1 -- ** to turn on the fan**
Now we can make whatever client we want (MVC client app, or
Android/iOS app, or even a command line based noGUI app).

14. AngularJS frontend

Create buttons with asynchronous calls to rest
API

Responsive UI + Material/Bootstrap themes.
Such design, much awesome.

Can also turn into Android/iOS clients using
Ionic etc.

15. GPIO/I2C run through

General Purpose I/O – Kernel interface to
control currents over sysfs.

Some info on why using C/C++ or shell to
actually control the currents is more efficient
than Python/Node.