For billions of tablets and smartphones used worldwide, touchscreen technology can be used as a powerful sensor sans need for modification.
A typical touchscreen can be used to detect common ionic contaminants in drinking water or soil by dropping liquid samples on the screen, found for the first time and demonstrated by researchers at the University of Cambridge. In fact, the sensitivity of touchscreen sensor can be compared to a typical laboratory equipment, which would make it valuable for low resource needs.
Importantly, the proof of concept could be expanded for a wide spectrum of sensing applications, say researchers. This includes medical or biosensing diagnostics, by simply using the phone in our pocket. The results are published in Sensors and Actuators B.
Meanwhile, today, touchscreen technology is used extensively in our everyday lives. On a tyical smartphone, the screen is covered in a grid of electrodes, and on experiencing disruption in the local electric field of the electrodes from the finger, the phone interprets the signal.
Importantly, other research teams have used the computational ability of smartphones for sensing applications, but this has relied on the camera or peripheral devices, or requires significant changes on the screen.
“The quest is to find if technology could be interacted in a different way, without requiring the need to change the screen fundamentally, stated the co-lead of the study. This implies instead of interpreting a signal from the finger, if a touchscreen could be used to read the electrolytes. This is because ions also interact with electric fields.
To begin, researchers carried out computer simulations, and then used stripped down, standalone touchscreen to validate the simulations.