In a September 2015 TED Talk, Harald Haas walked onto a stage and streamed a video. But his laptop wasn’t connected to the web via a cable or Wi-Fi, only a solar panel.
It was one of the first public demonstrations that light — in this case an LED — can beam data from the internet to a computer.
Called Li-Fi, the technology allegedly consumes less energy and is more secure than Wi-Fi. Since a device has to physically be in a room to get internet from Li-Fi, it’s also less prone to hacking.
But Li-Fi doesn’t stop with a cool demo. Haas, an inventor and mobile technology researcher at the University of Edinburgh, wants turn solar cells of all kinds into data receivers, including translucent ones that look like regular windows.
Haas and his colleagues initially developed Li-Fi using an LED lamp and a “standard, off-the-shelf solar cell,” he said in the TED video.
The researchers then spun their research into a company called pureLiFi. Their technology is based on the idea that solar panels can detect normally imperceptible fluctuations in light. Paired with a programmable LED, Haas said, they had a way “to receive information from the light and the solar cell.”
Haas encoded the internet data in the LED lamp through a controller, which converts that data into a series of flashing and dimming light that the human eye is too slow to see.
The solar panel — in this case the receiver — picks up the fluctuating brightness. A device that’s attached to the solar panel then decodes the light and turns it back into data, feeding the signal to the computer or smartphone.
Here’s an illustration that shows how this one-way transmission works.
To show the light on stage at TED was transmitting the video data to his laptop, Haas blocked the solar panel with a black card
This instantaneously stopped the streaming video of the blue clouds:
Haas also showed how Li-Fi works during in non-ideal conditions by draping a handkerchief over the solar panel. Even though less energy hits the solar panel, the computer stays connected to the light-based internet feed.
It remains to be seen what this admittedly clunky device would look like on a phone, but most technologies have a habit of shrinking until we take them for granted.
Haas thinks Li-Fi could be implemented in existing solar cells on roofs to “act as a broadband receiver” from any light source outfitted with the technology.
The applications could extend to “translucent solar cells integrated into windows,” Haas said, where a far-off light source like a laser could pulse a web connection to a home. It might also be useful in hospitals, where many wireless communications can interfere with sensitive medical equipment.
At home, Li-Fi users could worry less about neighbours competing with a Wi-Fi router’s signal strength. To get the signal, you have to physically be in the same room as the LED transmitter — so it’d be more secure, too.
Haas hopes to bring his invention to market within the next two or three years, but how that might work remains to be seen. Many people already have solar cells, but they’d still have to invest in a lot more than a wireless router if they want to use Li-fi. And it’s not truly wireless, since you’d still need to connect a device to your laptop to get a signal (unless the market adoption is wide enough that a transmitter comes built-in).
Also, not all homes are outfitted with LED lights or solar cells, and you might need to install Li-Fi bulbs in every room to get a clear signal. But pureLiFi says reflected light from an LED should be enough to provide a connection.
You can watch Haas and his full demo in the TED Talk below.
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