University of Michigan researchers last month announced that they have created the first prototype of a millimeter-scale computing system -- one so small that it just covers the letter N on a penny.
The computer, called the Phoenix chip, is about 1 cubic millimeter and was designed to be implanted in the human eye to monitor the intraocular pressure of glaucoma patients.
"This is the first true millimeter-scale complete computing system," Dennis Sylvester, a University of Michigan professor and one of the researchers on the project, said in a statement.
Within the computer is an ultra-low-power microprocessor, a pressure sensor, memory, a thin-film battery, a solar cell and a wireless radio with an antenna that can transmit data to an external reader.
The chip uses very little power: It has an extreme sleep mode that wakes the computer up briefly every 15 minutes to take readings, and the chip uses only 5.3 nanowatts each time it turns on.
The researchers said that tiny computers could one day be used to track pollution, monitor structural integrity, perform surveillance, or make virtually any object smart and trackable. "We can collect data, store it and transmit it," said Sylvester. "The applications for systems of this size are endless."