Japanese boffins have measured the spin-speed of toilet rolls to work out who's on the loo.
The idea, apparently, is that because a throne is a good place to collect health monitoring data, the researchers wanted a reasonably non-invasive ID technique. One that wouldn't get bogged down in the obvious privacy issues of trying to install cameras or ask people to ID themselves when they're in a hurry.
The research was led by Japan's Tsukamoto Terada Laboratory at Kobe University.
As the boffins' paper (PDF) notes, how someone spins the chocolate wheel is probably very personalised, since nearly nobody's paid much attention to whether people they know turn it quickly or slowly, smoothly or not.
So they stuffed a TSND121 Bluetooth gyroscope into a loo roll, and so they didn't need to hang around nearby with a suitable receiver, they sent it on to a PC with a WiFi relay.
The system, they write, “extracts feature values from the rotation of a toilet paper roll, such as the length of paper used and the maximum rotation speed. Then, the system identifies the user with the feature values.”
And the authors say it's privacy-protecting, since “only angular velocity is obtained” (we're not sure how that relates to privacy either), and “the user does not have to carry any devices because the system is completely installed in the environment”.
You'll be pleased, we bet, to know that the identification got more accurate the more times a visitor spun. For a five-person group in a “practical environment”, the researchers say, the average accuracy was 69.2 percent.
In the laboratory environment, someone whose habit was to pull on the roll four times would be correctly identified 92.5 percent of the time.
The paper was put together for a Pervasive Smart Living Spaces workshop organised by Sweden's Malmö University, the Rochester Institute of Technology and the IEEE. ®