Boffins build a chip on a pen tip

BOFFINS at the University of Michigan have reduced a computer in size so it fits on a pen tip.

The prototype computer is an implantable eye pressure monitor for glaucoma patients and researchers claim it's the first millimetre-scale system.

The technology shrink was the result of applying what's known as Bell's law.

Like Gordon Moore's two-year transistors doubling law, Bell's law says cheaper and smaller technology is introduced every decade. The actual size of a computer decreases by two orders of magnitude every ten years and this has held up since Big Blue's mainframes from the 1960s.

The researchers were looking for a way to track pressure and gain data from an eye in practical and economically viable ways. The entire computer uses a low powered microprocessor, sensors, thin film battery, a solar cell and a wireless radio.

There is a third-generation 'Phoenix' chip with power gating architecture that consumes only an average of 5.3 nanowatts. It achieves this trick by only being woken up to collect data every 15 minutes. It can also store a week's worth of data and re-charge on 1.5 hours of sunlight.

What makes the dinky computer even more effective is the WiFi radio that can transmit data. That means of course that devices likes these have the potential to be networked as well.

The technology will be used for medical purposes but the team reckons its potential applications are many.

"We can collect data, store it and transmit it. The applications for systems of this size are endless," said one of the team members. µ