Directly harnessing the sun’s energy for wireless data transmission to electronic devices could be possible. A smart glass system created by KAUST researchers can regulate the sunlight that passes through it, embedding information into the light that can be read and decoded by devices in the room.
Compared to traditional Wi-Fi or cellular data transfer, using sunlight to send data would provide an eco-friendlier type of communication.
Basem Shihada had the idea to employ sunlight while researching data encoding into an artificial light source.
I was simply hoping to use a cell phone camera to record a video of the encoded light stream to try to decode the video to retrieve the data; that's when I thought, why not do the same with the sunlight? This would be much easier and can be done over the cell phone camera too. So, we began to explore sunlight as an information carrier.
Basem Shihada, Associate Professor, Computer, Electrical and Mathematical Science and Engineering Division, King Abdullah University of Sciences and Technology
The team has now created a two-part sunlight communication system.
There is a light modulator that can be embedded in a glass surface and an in-room receiver. The modulator is an array of our proposed smart glass elements known as Dual-cell Liquid Crystal Shutters (DLSs).
Osama Amin, Research Scientist, Networking Research Lab, King Abdullah University of Sciences and Technology
The liquid crystal shutter array would only require 1 watt of power to operate, which a small solar panel can provide. It would act as a filter to encode signals into the light as it passes.
According to Sahar Ammar, a member of Shihada’s team, data has traditionally been encoded in earlier optical wireless communications system designs by altering the light intensity.
But if the frequency of these intensity changes is too low, it can be detected by the human eye and cause an uncomfortable flicker effect.
Sahar Ammar, Ph.D. Student, Networking Research Lab, King Abdullah University of Sciences and Technology
Therefore, the DLS is made to control light's polarization, a light property.
Ammar added, “Change in light polarization is imperceptible to the eye, eliminating the flicker problem. The communication system works by changing the polarization of the incoming sunlight at the modulator side. The receiver can detect this change to decode the transmitted data.”
The team’s calculations demonstrate that the suggested configuration could carry data at 16 Kilobits per second.
Shihada concluded, “We are now ordering the necessary hardware for a testbed prototype implementation. We would like to increase the data rates from Kilobits to Mega- and Gigabits per second.”
Ammar, S., et al. (2022) Design and Analysis of LCD-Based Modulator for Passive Sunlight Communications. IEEE Photonics Journal. doi:10.1109/JPHOT.2022.3200833.