A fascinating prototype of sensor the size of a cubic millimeter has been developed with a lot of brilliant technology inside—never mind that its specifically meant for glaucoma patients. The device takes measurements every 15 minutes and uploads the readings once a day by 400 and 900MHz frequencies. Because of the small size of its antenna it needs 47 microwatts to transmit a single bit using a pulse from a capacitor, since the built in battery only provides 40 microwatts. The capacitor repeats this process until it completes the total of 1.5Kb of data. The battery lasts for 28 days, but the system has one more trick in the form of a solar cell which charges itself over 10 hours of indoor of 1.5 hours of outdoor lightning.
The system hasn't been trialed in humans yet, and they're still several years away from doing so, but the team's already talking about color matching the systems to eyes so the sensors can make fashion statements. I can't help but think that a system like this could be paired with camera systems the size of sand. One day!