Mine is Smaller Than Yours
The world of innovative technology is competitive, with claims of the smallest this, the fastest that, the strongest X or the lightest Y commonly coming from research labs across the globe. In March this year, computer giant IBM announced that it had produced the world’s smallest computer – something which the University of Michigan in the US previously accomplished in 2015 with its 2 x 2 x 4 mm Micro Mote. It didn’t take long for the latter to reclaim its title, however, as the Michigan team announced in June that their new device, which measures a miniscule 0.3 mm, is so small that a grain of rice looks huge in comparison.
The Michigan team’s cube-like device has sides that measure just 0.3 mm each, making it about one-tenth the size of the previous world’s smallest computer – IBM’S aforementioned sand-grain-sized device, which measured 1 mm x 1 mm. David Blaauw, a professor of electrical and computer engineering who led the development of the system together with several others, says that their device can fit into much smaller spaces, though there is another major difference. “The IBM computer can’t sense its environment – it can send a code identifying itself but it does not sense its physical environment,” Blaauw explains.
Despite its teeny size, the Michigan team’s new device is fitted with a processor, RAM, a photovoltaic power system, and a wireless transmitter and receiver. But because they are too small to have conventional radio antennae, they receive and transmit data with visible light. A base station provides light for both power and programming, and also receives the data back. The device, designed as a precision temperature sensor, essentially converts temperatures into time intervals, defined with electronic pulses. The intervals are measured onchip against a steady time interval sent by the base station and then converted into a temperature. As a result, the computer can report temperatures in regions as small as a few cells, precise to about 0.1 °C.
The system is remarkably flexible and could be reimagined for numerous purposes. The team chose precision temperature measurements, however, because of a need for such tech in oncology, concerning both cancer detection and treatment. The team’s longstanding collaborator, Gary Luker, a professor of radiology and biomedical engineering, has a lot of questions concerning temperature in tumours. The theory is that cancer cells are hotter than surrounding healthy tissue, though not enough data exists to prove this theory. Thus, researchers hope to test this hypothesis using this precise, tiny temperature sensor. Luker has said that, because the temperature sensor is both small and biocompatible, it can be implanted into a mouse, for example, and have cancer cells grow around it. “We are using this temperature sensor to investigate variations in temperature within a tumour versus normal tissue and if we can use changes in temperature to determine success or failure of therapy,” he has said.
As happened with the Michigan team’s previous tiny computer, the Micro Mote, a myriad of other potential uses may be found in time. According to Luker, when they first developed the Micro Mote, they didn’t yet know all the things for which it would be useful, but once they published it, dozens of inquiries came flooding in. Current applications of the Micro Mote include pressure sensing inside the eye for glaucoma diagnosis, cancer studies, oil reservoir monitoring, biochemical process monitoring, surveillance – both audio and visual – and researching the behaviour of snails.
While there’s little doubt that the Michigan team’s latest device is remarkable, doubt has been cast on the team’s claim to tiniestcomputer fame, as some are questioning whether these devices – IBM’S included – can legitimately be called computers. The reason being, if you unplug a desktop or laptop computer, its programs and data are still there when it reboots once the power returns, whereas the micro-devices lose all prior programming and data if they lose power. Indeed, Blaauw has asked this very same thing. “We are not sure if they should be called computers or not. It’s more of a matter of opinion whether they have the minimum functionality required.”
As time marches on and tech gets ever more extraordinary, scientists and engineers will likely come up with plentiful uses for this minute computer – and possibly even a smaller competitor.