The vibrations from an iPhone鈥檚 ringtone can be used to measure the viscosity of a liquid, which could allow it to detect whether water is polluted or to test for kidney conditions and pregnancy by measuring the levels of protein or hormones in urine.
Yandao Huang at Shenzhen University in China and his colleagues built a 3D-printed cup with a mount on the outside designed to securely hold an iPhone 7. They then used the phone鈥檚 vibrating motor to agitate dozens of types of liquids inside the cup; its built-in motion sensor measured the friction between the liquid molecules by detecting reflected motion waves.
The researchers used several stages of signal processing to remove noise from the measurements, eliminating the vibration from the phone itself, before using the amplitude of the waves and the rate of their decay to calculate the liquid鈥檚 viscosity.
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Huang and his team were able to distinguish between 30 kinds of liquid with an average accuracy of more than 95 per cent. Bacteria, dirt or minerals change a liquid鈥檚 viscosity, allowing the phone to tell the difference between them. It differentiated between tap water, rain water, puddle water and water that had been exposed to the air for a long time with an error rate of just 2.5 per cent. Huang says that it could lead to a simple test for measuring the safety of drinking water.
Experiments also showed that the set-up could accurately measure uric acid and proteins within urine and could therefore be used as an at-home diagnostic test for kidney-related conditions, such as nephritis. It could also be used to detect pregnancy by measuring hormones, although it is likely that a person would have to take a test on several consecutive days to get an accurate result, says Huang.
He concedes that there are problems to overcome before the technique could be used outside the controlled setting of a laboratory. In experiments, the temperature was strictly maintained as the viscosity of liquids can change as they heat, but this wouldn鈥檛 be possible in the real world. The researchers also hope to adapt the technology so that it works with any receptacle.
鈥淚f we want to measure without using those 3D-printed cups, we have to improve our mathematical model, and also we have to consider how to adjust the problem for different bottle sizes and bottle types, like plastic, metal and glass, which will affect the mathematical model,鈥� says Huang.
The current model also struggles to identify mixed liquids. It could identify black coffee and cream separately, but it may be confused by black coffee with cream. Other measurements may need to be added to create a robust system that works on any combination of liquids, says Huang. 鈥淚f we can combine different kinds of methods to measure the different properties of our liquids, like viscosity combined with surface tension, that will contribute to a more robust and accurate measurement.鈥�
搁别蹿别谤别苍肠别:听The 27th Annual International Conference On Mobile Computing And Networking, DOI:
