A wireless connection using an LED bulb has been tested in an Estonian office. The technology achieved a 1Gbps transfer, though the theoretical maximum is 224Gbps.

The basic principle of “Li-Fi” is the same as Wi-Fi, just using wavelengths of visible light rather than radio waves. Instead of using a router, it involves varying the current to an LED bulb, which changes the intensity of the light. That’s then picked up by a photodetector and turned back into an electrical current, which in turn acts as a data signal.

Although the variations in the light intensity are enough to transmit data accurately, they can’t be detected by the human eye. That means it’s possible to change intensity at a rapid enough pace for fast data transfer without causing any flickering which could be distracting or even trigger seizures.

The theory behind using the technology would be that you could create a local network with each computer being connected to a photodetector dongle that lies underneath an overhead bulb.

The idea does have some major limitations. As you’d imagine, the system can’t transmit data through walls, so for a home network you’d need at least one bulb in each room and for them all to be wired together. And while filters can let the system still work while sunlight is coming into a room through a window, the concept doesn’t work outdoors at all.

In practice there are only a few situations where the system might be suitable. One would be when it’s built directly into a newly constructed home or office, with one possible setup being to combine traditional Wi-Fi with a few “Li-Fi” points for situations where you need a high-speed but wireless connection.

Another is in aircraft where you’d have the benefit that lightwaves pose no risk of interfering with radiowave signals. It could also be used in hospitals where wireless signals can cause interference with medical equipment (and vice versa.)