New app would put a working thermometer on your smart phone

The thermistors that detect when your smartphone is overheating might soon do the same for you, thanks to a new app in the works.

“We present FeverPhone — a smartphone app that estimates a person’s core body temperature by having the user place the capacitive touchscreen of the phone against their forehead,” the developers wrote.

Normal body temperature ranges from 97.5 degrees Fahrenheit to 99.5 F. Most health care providers consider a fever to be 100.4 F or higher, while a temperature of 99.6 F to 100.3 F is considered a low-grade fever.

Since the onset of COVID-19, taking one’s temperature has been routine before going to a doctor or other health care setting. But it isn’t always convenient to carry a thermometer around.

Because the thermistors in digital thermometers are the same as those that measure the internal temperature of your smartphone, researchers were able to use them to make their app work.

The researchers found the sensors could track the heat transfer between a person and their phone using the device’s touchscreen, New Atlas reported.

After calibrating the app using water in balloons, it was tested on humans. Participants held the touchscreen to their foreheads for 90 seconds, and the FeverPhone was accurate to 0.41 degrees, which is within the clinically acceptable margin of error.

“We started with smartphones since they’re ubiquitous and easy to get data from,” Joseph Breda, lead author of the study, told New Atlas. “I am already working on seeing if we can get a similar signal with a smartwatch. What’s nice, because watches are much smaller, is their temperature will change more quickly. So you could imagine having a user put a Fitbit to their forehead and measure in 10 seconds whether they have a fever or not.”

The researchers are still fine tuning the app to be used on a wide variety of phones, so it isn’t available yet for download.