Normal touch screens can also detect contaminated water

We take it for granted that the water that comes out of the kitchen tap is safe to drink, but this is not always the case in other parts of the world. Thus, researchers from Cambridge University are developing a new approach to testing for contaminants using a device that billions of people already use every day.

Modern capacitive touchscreens (the kind that can easily detect the most subtle finger taps instead of forcing users to press hard on the screen) feature an invisible grid of electrodes that carry a very small electrical charge. When your conductive finger touches the screen, it changes the charge level at a specific location that the smartphone can detect based on grid coordinates. It’s a crudely simplified crash course in how the technology powering modern touchscreens works, but what’s important is their use of a changing electrical charge.

In one recently published article, researchers at the University of Cambridge explain how a The touchscreen, the same hardware used in smartphones and tablets, has been shown to be able to detect electrically charged ions in an electrolyte. Different liquids were injected onto the surface of the touchscreen and using the standard software used to test these screens, the researchers were able to differentiate the samples based on how “fluids all interact differently with electric fields. of the screen as a function of the ion concentration. and their load.

Touchscreens used in mobile devices are tuned and calibrated to better respond to finger interactions, but researchers believe that by changing the design of the electrodes, even in a small area of ​​the screen (a custom app could indicate exactly where a sample is to be placed) the sensitivity could be optimized to detect contaminants in samples such as soil and water.

Be able to detect ions using Touch screens in consumer devices mean that serious problems associated with arsenic contamination in drinking water could be more easily avoided without the need for additional test equipment. Arsenic is considered a group A carcinogen linked to cancers of the bladder, kidneys, liver, lungs and even skin. It can be detected using simple color change test strips, but they can be expensive. Therefore, finding a way to leverage existing devices for such testing is a more practical approach to the problem.

Ultimately, researchers hope to find ways to further improve the sensitivity of touchscreen technology so that it can detect a wide range of molecules, including heavy metals like lead, another problematic contaminant in water. affecting millions of people around the world. Companies making smart mobile devices should be prepared to spend the extra money on upgrading the capabilities of the touchscreens they use, but given that companies like Apple have focused in recent years on the benefits for the environment. health of their devices, this may not be the case. this hard of a sale.