New Data Chip Activates a Secret Message When You Breathe On It
Researchers have been hard at work coming up with new ways to safely store information than traditional magnetic disks and optical storage, and that’s led to some uncanny ways to unlock hidden data.
One such method has been developed by engineers at the University of California San Diego (UCSD), an optical device that responds to changes in humidity. In practice, this means that breathing on the device could trigger the reveal of hidden images and information within a fraction of a second.
The technical details of the new invention were published last month in the journal Light: Science & Applications.
According to the team, information can be inscribed onto the two-layered chip, about the size of a postage stamp, across different humidity levels.
“You could encode different pieces of information in different layers stacked on a single space and choose which one to access based on the humidity,” Abdoulaye Ndao, the study’s senior author and an engineer at UCSD, said in a statement.
Costly storage
Optical storage typically refers to physical devices that encode data via light sources. According to the study, these represent a “compelling” alternative to electronic approaches, and recent advances have allowed researchers to more freely control different surfaces and their interactions with light sources. That said, many are inherently costly and difficult to scale, the paper added.
What’s more, building and recording data onto an optical device is one thing; retrieving said data later on is another. To bypass these challenges, the team opted for hydrogels that just require moisture for optical response and a relatively cost-efficient alloy, antimony trisulfide, to evaluate whether these alternatives could work as intended.
“You can imagine using this as a built-in security feature with the environment acting like a key that unlocks different pieces of information,” Asad Nauman, the study’s first author and a postdoctoral researcher at UCSD, said in the statement.
Keeping the records
The top hydrogel layer of the new device is a soft material that swells under humid conditions. Information is written onto the bottom layer using laser sources. A tiny gap between the two layers changes the spacing between them as the hydrogel shrinks and expands, therefore shifting how light reflects off the material. Image and color changes on the device occur within roughly 300 milliseconds, the paper reported.
It’s also quite easy to reuse the device; the bottom layer can be wiped and re-encoded as needed, whereas the hydrogel just needs to be washed and repatterned with UV light, according to the study. Again, the design is relatively low-cost and can be produced at scale, the researchers said, meaning it has good potential for many fields.
“One example would be something like a credit card security tag, where you can blow on it and reveal a hidden code,” Nauman mused. “Another application would be an environmental sensor that changes color as the humidity changes.”
