Lyza Danger Gardner - JavaScript on Things: Hardware for Web Developers

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Developmental editor: Susanna KlineReview editor: Ivan MartinovicProject editor: Kevin SullivanCopyeditor: Andy CarrollProofreader: Melody DolabTypesetter: Gordan SalinovicCover designer: Leslie HaimesCover and interior illustrations: Lyza Danger Gardner

ISBN 9781617293863

Printed in the United States of America

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On a late summer day in 2013, I stood on a stage in a large tent on the grounds of Bletchley Park in England, the site where British codebreakers (famously including Alan Turing) defeated the Enigma machine in World War II. It was one of the better days of my life, as two fundamentally wonderful things had just happened.

First, Id just somehow managed to win a hacking contest (thats why I was onstage). The National Museum of Computingalso located on the grounds of Bletchley Parkwas seeking tech help in creating web-based, interactive timeline exhibits. Id stayed up through the night, extending an open source JavaScript library and building a prototype: this was my entry, which was, to my great delight, declared best in show. The second wonderful thing was that Id won a prizeand not just any prize.

The reward I received was one of the original Arduino Uno starter kitsan Arduino board, a collection of electronic components, and an instructional book. It profoundly changed my life. Id later find that combining my newly learned electronics skills with the stuff I did every daycoding open source, standards-based websites and appsresulted in one of the most fascinating alchemies Id ever experienced: JavaScript on Things. That is, I could use the JavaScript I already knew as a turbo boost to electronics hacking and the internet of things (IoT).

That came later, however. Initially, I learned how to construct simple electronic circuits by working through the examples in the kits book and, later, avidly searching the web to learn more. I learned how to apply logical control to these circuits by programming the Arduino Unos microcontroller, writing simple sketches (programs) in Arduinos (very) C/C++-like language, optimized for the boards (very) limited program space and memory.

And then, at the end of 2013, I discovered Johnny-Five. The open source Node.js framework was young at the time, but already powerful. Instead of writing lower-level, constrained Arduino code, I could write higher-level JavaScript programs to control my Uno. I thought, Wow, if Id only discovered this earlier.

The combination of JavaScript and microcontrollers isnt just a parlor trick, performed for the sake of coating the entire known world with JavaScript. At first, even I, a Node.js adherent, was skeptical: maybe this is pointless; maybe it will never take root.

Dont worry. Its not, and it did.

Adding JavaScript into the mix perversely simplified my experience, and made prototyping little projects much, much faster. I could use development workflows that were more familiar to me as a web developer. I didnt have to concern myself as much with lower-level memory and resource optimization. Johnny-Fives encapsulation of behavior into high-level component classes is intuitive: the resulting code can be cleaner and easier to work with than many Arduino libraries. And it allowed me to take advantage of the almost fathomless depths of the worldwide Node.js ecosystem via npm. I could simply import modules, just like any other Node.js script out there. It was wonderful.

I want to be very clear: theres nothing wrong with Arduino or more traditional C-based microcontroller programming. There are very good reasons to care about memory management, for example, especially if youre writing firmware or making production devices. And Arduino is rather a miracle: its entire raison dtre is to make embedded electronics accessible to novices. Starting from scratch with Arduino and the Arduino programming language is a perfectly reasonable, surmountable approach.

But JavaScript can help web developers get up to speed with electronics faster. For one thing, introductory materials for Arduino (and other platforms) often assume no pre-existing knowledge of programming whatsoever, which means you may end up wading through explanations of what an array is and how loops work. The finicky constraints and particulars of microcontrollers can be distracting when youre just learning how things work. IDEs can be clunky. In some cases, you can end up spending a lot of time getting things configured and not much time making things actually happen. JavaScript has the power to abstract much of this away, letting you focus on the essential new things you need to learn.

From that notion, this book arose: the idea that JavaScript can serve as a gateway to electronics, making it easier for more people to learn how to make cool stuff with a minimum of cognitive pain. JavaScript is the most popular programming language in the world, the de facto language of the web; and the internet of things and maker culture is tantalizing both creatively and commercially. Why not make a happy blend of the two?

At the end of the day, this stuff is fun. Its a kick to be able to dream up and make real your own inventions. Its confidence-lifting to have a basic competency with low-voltage electronic circuits, and to understand how embedded systems work in the real world.

Maybe youll really love this like I do. Maybe youll help contribute to open source projects. Maybe youll construct a wildly clever gadget. Maybe youll teach other people what youve learned.

Perhaps youll simply have fun. That, on its own, is more than enough.

My gratitude starts right where my love of hardware hacking began: with the Over the Air conference crew and The National Museum of Computing (UK), whence my initial Arduino Starter Kit originated. None of this would have happened without that serendipitous event. Dan Appelquist, Margaret Gold, and Matthew Cashmorethank you for creating such a superb conference and inviting me to it, more than once, even!