It doesn't have to be built into a screen either; you could get this kind of sensation on a wooden or metal surface, through the fabric of your car seat or even on a cardboard sign, as well as on glass or plastic. And it doesn't have to be in the same place each time, so you can rotate a tablet and still have a "physical" home or Start button in the right place.
Doing away with physical buttons that move saves money (cutting the round hole in the glass of the iPad is expensive) and it saves a tiny bit of space (you could use that to put a bigger battery in or make the device smaller).
It also means there are fewer parts to fail or break and fewer ways for water to get inside if you drop your gadget. James Lewis of Redux thinks we might see the first products incorporating this technology in as little as a year's time.
Just use your phone
Angela McIntyre thinks that several of these extra technologies will come to devices you already use. Your TV remote control might get accelerometers so you can gesture to change the channel as well as pressing a button to turn the volume down.
Hillcrest designed a remote control that looked like a giant bracelet called the Loop. It didn't take off when it was introduced a few years ago but the company is in talks with several TV makers about adding it to high-end models. Samsung is including a remote with a trackpad for controlling its interface with some TVs this Christmas.
She's seen a lot of unusual ideas – from heads up displays in cars and screens that show one thing to the driver and a different image to the passenger sitting next to them, to shirts and gloves that give you the physical sensation of what's going on in the game you're playing to using galvanic skin response to turn different places on your arm into different buttons and controls. (Microsoft Research had a version of that but you had to wear a Kinect on your shoulder to make it work.)
Some washing machine manufacturers are looking at using voice control to simplify complex features, but McIntyre thinks it makes more sense to use the smarts in something you already have. "Why not us your smartphone as a controller?" It has touch, it has voice recognition, it has an accelerometer.
"It is easier for that device to figure out what you're doing. You're close to is so it's not like having the thermostat on the other side of the room trying to figure out what is a gesture and what is you playing with your kids. For at least the next five years, I think the most convenient device people want to use as their controller will be the smartphone."
In other words, the new interfaces are already here. They're just waiting for us to start using them.
- Now why not check out iPhone through the ages: just how much has it changed?