This digital Post-It is powered by your office’s horrible lighting

Offices are littered with Post-it notes. Some argue for their greenness, others aren’t so convinced. But in any case, a tiny reusable display might make a better alternative in the long term—if only it didn’t require any extra power. And it so happens, scientists at Microsoft Research have developed just that.

Featured in New Scientist, and dubbed an "energy harvesting situational display," Microsoft's invention is a Post-it sized chunk of e-paper, the same stuff used in Amazon's Kindles. And simply through some solar panels placed on the display’s back, it can generate enough electricity to not only run continuously simply by sipping on the ambient light inside an office, but to actually update its display anywhere from two to sixty times per hour, depending on light levels.

Calculators have operated off internal lighting for decades, but their LCD displays require a constant power flow to stay active, which takes up precious voltage needed for any other advanced functions. Microsoft used e-paper instead, which draws virtually no energy to hold an image, and expends it mostly only to update the image. However, that energy is largely dependent on the screen’s resolution—so by keeping the display at around 100 pixels, it can update within the limitations of indoor light.

This also leaves extra energy leftover, for Microsoft to divert to a radio antenna instead, meaning that its Post-it is actually Bluetooth-connected, too, and can be updated via a phone or tablet.

The display still lacks the quick, note-jotting UX of a good old Post-it note. However, the research is still important for two reasons. For one, it’s a proof-of-concept of a display that could be both connected and always-on, without access to power, which could be useful in a number of contexts beyond the office. One example Microsoft offers is placing such a display on a bike, assumably to tell you speed or simple directions. And given that e-paper only reads better in the sun, outdoor use makes a lot of sense.

Secondly, Microsoft has also demonstrated that its displays can serve as beacons for augmented reality applications. So when you mix these tiny displays with something like Microsoft's Hololens headset, suddenly this very low resolution screen can actually anchor very high fidelity, virtual information into your view.

Or, in other words, this power-free electronic Post-it could contain not just a quick doodle, but an entire library of information inside, floating just a glance away.