Programming for the Internet of Things

Programming for the

Internet of ThingsPeter Hoddie@phoddie@kinoma

#ieeeJanuary 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?

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Consumer IoT

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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

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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

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Standards in IoT• Industry impulse is to create

a new standard• Define boundaries of

new product categories• Ensure interoperability

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Everyone is trying

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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

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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

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Direct

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The Killer App for IoT is the same as the Killer App for PC and mobile:

The ability to run the apps you choose.

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No single killer app

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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!

Let’s explore the insanity

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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

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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

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• 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

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• 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

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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 forIoT devices look like?

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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();

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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();

};

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I2C Accelerometerlet 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);

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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

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Hello World

/* test.js */trace("Hello, world!\n");

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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 variablesTo 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

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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

to work on your project

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

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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

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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

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Scriptable IoT will lead us to theright 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

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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

Thank you!Peter Hoddie

@phoddie@kinoma

kinoma.com

Questions?Peter Hoddie

@phoddie@kinoma

kinoma.com