Who would think scientists would just let IBM's "world's smallest computer" boast go unchallenged, guess you didn't right? Well, the University of Michigan has produced a temperature sensing 'computer' measuring 0.04 cubic millimeters, or about a tenth the size of earlier rolled out IBM's record-setter. It's so tiny that one grain of rice seems big in comparison -- and it's so sensitive that its transmission LED could instigate currents in its circuits.
The size limitations made researchers to get creative to reduce the effect of light. They switched from diodes to switched capacitors, and had to fight the relative increase in electrical noise that comes from running on a device that uses so little power.
The result is a sensor that can measure changes in very small regions, like a group of cells in your body. Scientists have suspected that tumors are to some extent hotter than healthy tissue, but it's been hard to verify this until now. The minuscule device could both check this claim and, if it proves true, gauge the effectiveness of cancer treatments. They also envision this helping to diagnose glaucoma from inside the eye, monitor biochemical processes and even study tiny snails.
Why the air quotes around computer, then? The small size is leading the University to question what a computer really is. This does have a full-fledged processor (based on an ARM Cortex-M0+ design), but it loses all data when it loses power, the same way IBM's device does. That might be a deal-breaker for those who expect a computer to be more complete. Still, this pushes the limits of computing power and suggests that nearly invisible computing may be relatively commonplace before long.