Designed by the University of Michigan for implantation inside the eye of glaucoma patients, the millimeter-sized, all-in-one computer will be useful in wireless sensor networks, remote surveillance and other applications requiring on-chip trackable smarts, according to the researchers that built it.
"Ours is the first true millimeter-scale complete computing system," said University of Michigan professor Dennis Sylvester. He performed the work with fellow professors David Blaauw and David Wentzloff.
"Millimeter-scale systems have a host of new applications for monitoring our bodies, our environment and our buildings," said Blaauw. "When you get smaller than hand-held devices, you turn to these monitoring devices. There could be 10s to 100s of them per person and it’s this per capita increase that fuels the semiconductor industry’s growth."
The first application to which the team put their millimeter-scale computer was to monitor the pressure inside the eye of glaucoma patients to monitor the progress of that disease. Packaged in a volume of less than one cubic millimeter, the system contains a microprocessor, pressure sensor, memory, thin-film battery, a solar cell for recharging and a wireless radio and antenna for transmitting stored measurements.
The current prototype is the third generation of what the researchers call their Phoenix effort, which the researchers claim consumes 10 times less active power and 30,000 times less standby power, than conventional processors. This latest iteration of the Phoenix consumes an average of just 5.3 nanoWatts, waking every 15 minutes to take a measurement and transmit its results. About 1.5 hours of sunlight or 10 hours of indoor lighting are required to recharge its battery.