How to modulate daylight to transmit data

Researchers in Saudi Arabia are exploring an unusual idea: modulating daylight coming through a window to transmit data.

KAUST smart glass researcher Sahar Ammar

The scheme will use quadrature amplitude modulator and a pair of liquid crystal shutters to change the polarisation of light as it passes.

“Change in light polarisation is imperceptible to the eye, eliminating the flicker problem,” said researcher Sahar Ammar (pictured) of KAUST, the King Abdullah University of Science and Technology.


The team has gone deep into the theory, including how information will propagation within rooms.


Depending on requirements, the modulator could need as little as ~1W, and could be powered by a solar cell, according to KAUST, where a 16kbit/s proof-of-concept is being built.

The theoretical work is published as ‘Design and analysis of LCD-based modulator for passive sunlight communications‘ in the IEEE Photonics Journal. The full, maths heavy, paper is available without payment.

Steve Bush

Steve Bush is the long-standing technology editor for Electronics Weekly, covering electronics developments for more than 25 years. He has a particular interest in the Power and Embedded areas of the industry. He also writes for the Engineer In Wonderland blog, covering 3D printing, CNC machines and miscellaneous other engineering matters.

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