The phone inside you

If you were to have a heart attack, you would probably be very happy to have a pacemaker implanted in your body. It's just an electronic device whose job is to keep you alive. That sounds worth having! Implants like that, placed in people's bodies by surgeons, are now routine, but why stick with medical devices? After all, it's a constant pain having to look for the TV remote or game console all the time. Mobile phones are too easily stolen too. You also have to leave them behind when you go swimming or to school lessons. Why not get them surgically implanted in your body just like a medical device? Then they would always be there when you need them, and you'd no longer have to worry about missing calls because you took too long to get the phone out of your bag. Problems solved!

Implanting chips under the skin is no big deal in itself. Pets are routinely chipped by their owners, after all. With something like a mobile, the difficulty comes more in how to actually interact with it. Where are the buttons to press? How do you handle not having a screen? PhD student Christian Holz and a team of researchers in Toronto Canada and Germany have been exploring these sorts of questions. To test their ideas they even went as far as implanting devices into dead bodies.

Tummy Buttons

The first challenge to overcome if you implant a device inside someone is what do you do for buttons? How do you dial a number for example? One way would be to switch to a voice-activated interface. Sometimes, such as for privacy or when it's noisy, buttons are just more convenient, though. In fact, you can still, in theory, have buttons on an implanted device or even similar things like touch sensors. Light detecting sensors might also be able to tell when a finger is hovering over a particular position. Light does pass through the skin to some extent. Try it. Shine a strong torch into the palm of your hand. In the dark you can see the glow at the back of your hand. Of course that leaves the problem of remembering where those pesky buttons actually are. Perhaps a tattoo would help! An alternative would be to not bury devices completely in the first place but have them sticking out of the skin. A tiny camera could be implanted in this way and then be able to detect gestures in front of it.

Of course there are problems to be overcome - would you want your phone to accidentally dial your partner every time someone gave you a hug? A clear way to switch the device on and off is needed that couldn't be done accidentally just as phones use a variety of mechanisms to lock them in your pocket.

As a first attempt to find out how various implanted devices might work in reality the Canadian-German team tested a series of input and output devices. This included a normal button, a sensor that could detect pressure and another that could detect a person tapping it, and finally sensors that could detect something hovering above the skin. Output sensors included an LED to flash a light through the skin, a motor that vibrated to give tactile feedback and a speaker.

The devices were implanted by surgeons into the body of an 89-year-old man who had died and left his body to science. His body had been lightly embalmed to keep the skin flexible. They then set up a test rig that used a piston to trigger the input devices in controlled ways. They tested each a series of times as well as testing how well the output devices worked. The tests showed that all the input and output devices did still work through the skin.

Skin deep

Having shown the devices still worked, the next step was to find out how real people would react to the idea of using devices under the skin. Rather than actually implant them though they used an artificial skin that felt like real skin - the sort of thing used by make-up artists in films. The device was laid on the person's arm and covered with the artificial skin. They got people to play a simple game that involved responding to outputs from the device by using different inputs: for example if the device emitted a sound they had to press the button, if it vibrated they had to tap the tap sensor. The faster they were at responding correctly, the higher their score. To make it more realistic the game was played while the person was doing a series of real tasks out on the streets of Toronto like ordering coffee and getting a newspaper.

So how well did the devices work? All were relatively easy to use though noone liked using the pressure sensor and the LED was the hardest to notice. It could only be seen blinking when directly looked at.

The participants got some odd looks, but that aside the team demonstrated that implanted devices are feasible. How long before you will be 'wearing' one just for the convenience?