Making Things Talk

18 MAKING THINGS TALK

It Starts with the Stuff You Touch

All of the objects that you’ll encounter in this book, tangible or intangible, will have

certain behaviors. Software objects will send and receive messages, store data, or both.

Physical objects will move, light up, or make noise. The first question to ask about any of

them is: what does it do? The second is: how do I make it do what it’s supposed to do?

Or, more simply, what is its interface?

An object’s interface is made up of three elements. First,

there’s the physical interface. This is the stuff you touch.

The knobs, switches, keys, and other sensors that make

up the physical interface react to your actions. The

connectors that join objects are also part of the physical

interface. Many of the projects in this book will show you

how to build physical interfaces. Every network of objects

begins and ends with a physical interface. Even though

some objects in a network (software objects) have no

physical interface, people build their mental models of

how a system works based on the physical interface. A

computer is much more than the keyboard, mouse, and

screen, but that’s what we think of it as, because that’s

what we see and touch. You can build all kinds of wonderful

functions into your system, but if those functions aren’t

apparent in the things people get to see, hear, and touch,

your wonderful functions will never ...