Researchers at the University of Washington say they’ve found a way to turn your smartphone into a thermometer with a new app called FeverPhone. This is reported by Gizmodo.

Their solution does not require additional adaptations or hardware upgrades. Smartphones rely on components called thermistors to measure the temperature of the device’s internals and activate safeguards to prevent them from overheating.

Using the FeverPhone seems simple, but it requires users to hold the device by the corners and press its touchscreen to their forehead for about 90 seconds. This was found to be the ideal amount of time to transfer sufficient body heat to the device. And because forehead interaction is captured by the touchscreen, it lets the device and app know when a measurement is being made on purpose.

During a clinical trial at the University of Washington School of Medicine’s Emergency Department, 37 participants tested the app, including 16 with a mild fever. The obtained results were compared with the readings of an oral thermometer. FeverPhone was able to determine a user’s body temperature with “an average error of about 0.41 degrees Fahrenheit (0.23 degrees Celsius),” matching the accuracy of home thermometers.

It was previously reported that the new flagship of Google may get the ability to measure a user’s body temperature. The infrared sensor is inside the metal panel next to the camera unit. Users will need to remove glasses or other accessories before taking the temperature. The process itself takes about 4 seconds.