Technology is getting smaller and more powerful all the time. Today’s phones pack more punch than the bulky PCs that sat on our desks ten years ago. Where is this trend going? Computers clearly aren’t going anywhere, but could the computer – the physical device we actually use – become so small that it effectively disappears?

Let’s start by looking at what makes up a computer. For the sake of this post, we’ll assume there are two simple components – the “brain” and the “body”.

The body and brain of a computer (click for full size)

The brain (CPU, hard drive, memory, etc) does the actual work. It gets smaller all the time, which has led to things like laptops, smartphones and tablets which only became possible because the brain got small enough. And if the brain keeps shrinking, even if it becomes microscopically small, that’s not a problem – after all, we don’t have to be able to see it or touch it.

The body is different because it must be big enough to remain usable. Keyboards the size of postage stamps wouldn’t be much fun, would they? The human form sets a minimum size threshold for the computer’s body.

Anyone who’s been through a 30-minute Angry Birds marathon will have learnt the hard way that smartphones aren’t great for sustained daily use (and, yes, I’m talking from personal experience here). We couldn’t use them like we use our main computers, which is fine because they can’t actually do what we need our main computers to do.

So far, the cramped form factors of these handheld devices are consistent with their capabilities – but this might be about to change. We’re nearly at the stage where the smartphone’s body can easily house a brain capable of working as a desktop or laptop PC.

The extended device

As smartphone’s brains become ready to replace our main PCs, the only thing stopping them will be their small bodies and the discomfort caused by extended usage. But does this need to be the case? What if the smartphone’s brain extended itself into larger, more ergonomic bodies?

Tomorrow's powerful smartphones could control a whole range of devices (click for full size)

I’ll admit, I find it difficult to get my head around such a small device projecting itself on to a large TV screen. Something about it seems counterintuitive. But I can see the benefits, and the technology’s already heading in this direction.

The latest batch of HTC smartphones feature a technology called DNLA which lets mobiles stream video to televisions and other compatible display devices. If your TV isn’t bleeding-edge enough to support DLNA, you can get an adapter to do the job instead. So you can use your TV to watch the movies on your phone, which is obviously preferable to spending two hours hunched over your Desire HD.

A more innovative approach has been taken by Motorola, whose forthcoming Atrix smartphone will be accompanied by a special dock – a much larger “body” that, when plugged in, turns the phone’s form factor into a laptop.

Motorola Atrix with laptop dock

This is much more interesting than just streaming video to a television. It represents a dramatic decoupling of the computer’s brain from its body, and points to a future where phones, as primary computing devices, are accessed through a wide range of interfaces. When we pick them up and turn them on they’ll behave like phones, but we’ll also interact with them through numerous devices in our immediate environment.

Today’s computer may gradually vanish – our laptops and PCs becoming mere peripherals, mindless bodies controlled by the brains in our pockets. And it might go even further as the brain continues to shrink. Who’s to say that a similar fate doesn’t await the smartphone itself, that they won’t also become mere interface devices controlled by computers we wear as watches or jewellery? This might sound a bit sci-fi, but research fields like ambient intelligence and ubiquitous computing have even more radical ideas than these about where we might be heading.