by Paul Curzon, Queen Mary University of London
(Updated from the archive)

Biology and computer science can meet in some unexpected, not to mention inhospitable, places. Who would have thought that the chemical soup in the nests of Petrels studied by field biologists might help in the development of futuristic dust-sized computers, for example?
Just Keep Doubling
One of the most successful predictions in Computer Science was made by Gordon Moore, co-founder of Intel. Back in 1965 he suggested that the number of transistors that can be squeezed onto an integrated circuit – the hardware computer processors are made of – doubled every few years: computers get ever more powerful and ever smaller. In the 60 or so years since Moore’s paper it has remained an amazingly accurate prediction. Will it continue to hold though or are we reaching some fundamental limit? Researchers at chip makers are confident that Moore’s Law can be relied on for the foreseeable future. The challenge will be met by the material scientists, the physicists and the chemists. Computer scientists must then be ready for the Law’s challenge too: delivering the software advances so that its trends are translated into changes in our everyday lives. It will lead to ever more complex systems on a single chip and so ever smaller computers that will truly disappear into the environment.
Dusting computers
Motes are one technology developed on the back of this trend. The aim is to create dust-sized computers. For example, the worlds smallest computer as of 2015 was the Michigan Micro Mote. It was only a few milimetres big but was a fully working computer system able to power itself, sense the world, process the data it collects and communicate data collected to other computers. In 2018 IBM announced a computer with sides a millimetre long. Rising to the challenge, the Michigan team soon announced their new mote with sides a third of a millimetre! The shrinking of motes will is not likely to stop!
Scatter motes around the environment and they form unobservable webs of intelligent sensors. Scatter them on a battlefield to detect troop movements or on or near roads to monitor traffic flow or pollution. Mix them in concrete and monitor the state of a bridge. Embed them in the home to support the elderly or in toys to interact with the kids. They are a technology that drives the idea of the Internet of Things where everyday objects become smart computers.
Battery technology has long been
the only big problem that remains.
What barriers must be overcome to make dust sized motes a ubiquitous reality? Much of the area of a computer is taken up by its connections to the outside world – all those pins allowing things to be plugged in. They can now be replaced by wireless communications. Computers contain multiple chips each housing separate processors. It is not the transistors that are the problem but the packaging – the chip casings are both bulky and expensive. Now we have “multicore” chips: large numbers of processors on a single small chip courtesy of Moore’s Law. This gives computer scientists significant challenges over how to develop software to run on such complicated hardware and use the resources well. Power can come from solar panels to allow them to constantly recharge even from indoor light. Even then, though, they still need batteries to store the energy. Battery technology is the only big problem that remains.
Enter the Petrels

But how do you test a device like that? Enter the Petrels. Intel’s approach is not to test futuristic technology on average users but to look for extreme ones who believe a technology will deliver them massive benefits. In the case of Motes, their early extreme users were field biologists who want to keep tabs on birds in extremely harsh field conditions. Not only is it physically difficult for humans to observe sea birds’ nests on inhospitable cliffs but human presence disturbs the birds. The solution: scatter motes in the nests to detect heat, humidity and the like from which the state and behaviour of the birds can be deduced. A nest is an extremely harsh environment for a computer though, both physically and chemically. A whole bunch of significant problems, overlooked by normal lab testing, must be overcome. The challenge of deploying Motes in such a harsh environment led to major improvements in the technology.
Moore’s Law is with us for a while yet, and with the efforts of material scientists, physicists, chemists, computer scientists and even field biologists and the sea birds they study it will continue to revolutionise our lives.
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EPSRC supports this blog through research grant EP/W033615/1.