Programming for the Internet of Things

Programming
for the
Internet of Things
Peter Hoddie
@phoddie
@kinoma
#ieee
January 9, 2016

@kinoma
Overview
• Looking ahead five years, based on what is happening
today.
• What does the code we program need to do?
• How will we be writing that code?
• Who will be doing the programming?

@kinoma
Consumer expectations
• These things are better than their predecessors
• Do more
• More configurable
• More reliable
• These things can work together with other things to
do even more useful stuff

@kinoma
Two kinds of standards
• To underpin markets
where massive
investment needed
• DVD (manufacturing
factories)
• 5G (cell towers)
• Wi-Fi (chips)
• MPEG compression
(silicon, software,
toolchain)
• To formalize (and
clean-up) existing
practice
• HTTP
• JSON
• JavaScript
• HTML
• MPEG-4 file format

@kinoma
Standards in IoT
• Industry impulse is to
create a new standard
• Define boundaries of
new product
categories
• Ensure interoperability

@kinoma
Too much. Too soon.
• It isn’t obvious what we want to do in the big picture
• Trying to create “underpinning” standards
• Not necessary for this market – investment level is
already unbelievably high
• Leading to bad standards
• Too much functionality
• Allow for too many possible futures
• Too big and complex to be practical

@kinoma
IoT needs time to evolve
• Experiments to discover what is possible
• Experience to know what works in the real world
• Too early for new standards
• Plenty of existing standards to build on

• Many suggest sending everything through the cloud
• Cloud acts as intermediary between devices and services
• Problems
• Too much data
• Internet isn’t always available
• Who’s cloud?
• Security – moving data around unnecessarily @kinoma
The cloud

• Devices must be able to communicate directly with
• Any cloud service
• Any other IoT device
• Any mobile app
@kinoma
Direct

The Killer App for IoT is the same as the
Killer App for PC and mobile:
The ability to run the apps you choose.
@kinoma
No single killer app

@kinoma
User-installed apps on IoT devices?
• Devices aren’t powerful enough.
• Too difficult for anyone but the most experienced
embedded programmers.
• It won’t be reliable.
• A security nightmare.
Insanity!

@kinoma
Let’s use a standard to help
• JavaScript is the closest thing we have to a
universal programming language
Web (Desktop)
Mobile (Apps and Web)
Server
Embedded

@kinoma
High level programming languages
on embedded systems
Relatedly, writing software to control drones,
vending machines, and dishwashers has become
as easy as spinning up a website. Fast, efficient
processors … are turning JavaScript into a
popular embedded programming language—
unthinkable less than a decade ago.

JavaScript for IoT
@kinoma
• JSON built in – de facto data format of the
web
• Exceptionally portable – OS independent
• Helps eliminate memory leaks so devices
can run for a very long time – garbage
collector

Secure foundation
@kinoma
• Sandbox
• Core language provides no access to network, files, hardware,
screen, audio, etc.
• Scripts can only see and do what the system designer chooses
to provide
• Secure – many classes of security flaws in native code are
nonexistent
• Uninitialized memory
• Stack overflow
• Buffer overruns
• Mal-formed data injection

First truly major enhancements to the language.
ES6 contains more than 400 individual changes
including:
• Classes – familiar tool for inheritance
• Promises – clean, consistent asynchronous
operation
• Modules – reusable code libraries
• ArrayBuffer – work with binary data
JavaScript 6th Edition – Features for IoT
@kinoma

@kinoma
How small a system can run
JavaScript?
• 512 KB RAM
• 200 MHz ARM Cortex M4
• Wi-Fi b/g
• Most complete ES6 implementation anywhere
• Open source

What does JavaScript for
IoT devices look like?

@kinoma
HTTP Client
let HTTPClient = require("HTTPClient");
let http = new HTTPClient(url);
http.onTransferComplete = function(status) {
trace(`Transfer complete : ${status}n`);
};
http.onDataReady = function(buffer) {
trace(String.fromArrayBuffer(buffer));
};
http.start();

@kinoma
HTTP Server
let HTTPServer = require("HTTPServer");
let server = new HTTPServer({port: 80});
server.onRequest = function(request) {
trace(`new request: url = ${request.url}n`);
request.addHeader("Connection", "close");
request.response();
};

@kinoma
I2C Accelerometer
let accel = new I2C(1, 0x53);
let id = accel.readChar(0x00);
if (0xE5 != id)
throw new Error(`unrecognized id: ${id}`);
accel.write(0x2d, [0x08]);
accel.write(0x38, [(0x01 << 6) | 0x1f]);
let status = accel.readByte(0x39);
let tmp = accel.readByte(0x32);
let x = (tmp << 8) | accel.readByte(0x33);
tmp = accel.readByte(0x34);
let y = (tmp << 8) | accel.readByte(0x35);
tmp = accel.readByte(0x36);
let z = (tmp << 8) | accel.readByte(0x37);

@kinoma
Adding ES6 to your product
• Just a few steps to get the basics working
• Get XS6 from GitHub
• Build it with your product
• Entirely ANSI C – likely builds as-is
• All host OS dependencies in three files
xs6Host.c, xs6Platform.h, and xs6Platform.6
• Update as needed for your host OS / RTOS

@kinoma
Hello World
/* test.js */
trace("Hello, world!n");

@kinoma
Hosting scripts in your code
#include <xs.h>
int main(int argc, char* argv[])
{
xsCreation creation = {
128 * 1024 * 1024,/* initial chunk size */
16 * 1024 * 1024, /* incremental chunk size */
8 * 1024 * 1024, /* initial heap slot count */
1 * 1024 * 1024, /* incremental heap slot count */
4 * 1024, /* stack slot count */
12 * 1024, /* key slot count */
1993, /* name modulo */
127 /* symbol modulo */
};
xsMachine* machine = xsCreateMachine(&creation, NULL,"my virtual machine", NULL);
xsBeginHost(machine);
xsRunProgram(argv(1));
xsEndHost(machine);
xsDeleteMachine(machine);
return 0;
}

Reading environment variables
To allow a script to do this trace(getenv("XS6") + "n");
trace(getenv("XSBUG_HOST") + "n");
xsResult = xsNewHostFunction(xs_getenv, 1);
xsSet(xsGlobal, xsID("getenv"), xsResult);
void xs_getenv(xsMachine* the)
{
xsStringValue result = getenv(xsToString(xsArg(0)));
if (result)
xsResult = xsString(result);
}
Implement xs_getenv in C
Add getenv function to
the virtual machine

Going deeper
• JavaScript is also great for building the
product
• App logic
• Communication
• Network protocols
• Hardware
@kinoma

@kinoma
Why use JavaScript to build your
product?
• Get it working faster
• Iterate incredibly fast
• Leverage code and techniques
developed by other JS developers
• Hardware independent; easy to re-use
in your next generation
• Re-use JavaScript code with Node.js cloud
service, mobile apps, and web pages
• Much easier to find JavaScript
programmers

Avoid the “100% pure” trap
• It doesn’t make sense to code
everything in script
• Native code is great
• Fast
• Access to native functionality
• Access to hardware functions
• Re-use of proven, reliable code
• Secure

@kinoma
But, you may say
JavaScript isn’t type
safe. My manager
insists….
JavaScript isn’t good
for big projects.
Google told me… Modules
JavaScript
isn’t fast

Programming is for more people
than you may imagine

Everyone can configure IoT devices
with mobile apps

IFTTT goes the next step with simple
rules

Visual programming is powerful,
an on-ramp to “real” coding

JavaScript has proven to be accessible
to designers, students, and engineers

@kinoma
Scriptable is scalable
• Your organization can’t implement everything itself
• Interactions with other devices
• Mobile experience
• Interactions with cloud service
• Building partnerships directly is slow, expensive, and limited
• Opening your product to Apps let’s individuals and
companies integrate your product with theirs
• Brings new abilities, new customers, access to new
markets

@kinoma
Scriptable IoT will lead us to the
right standards
• New “standard objects” for IoT to augment JavaScript built-
ins
• Common programming models
• Modules / libraries that are common across devices
• Perhaps enhancements to JavaScript for needs of IoT

@kinoma
Scriptable will realize potential of IoT
• We can’t organize to connect all
these devices and services
together
• This is not a central design /
control problem
• Organic exploration and growth
• Consumers will get the magic they
expect, just as the mobile app
ecosystem snapped into place

Thankyou!
Peter Hoddie
@phoddie
@kinoma
kinoma.com

Questions?
Peter Hoddie
@phoddie
@kinoma
kinoma.com

Programming for the Internet of Things

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