For obvious reasons, we have been forced to adopt different resources to take care of our health. Masks, hand sanitizer, soap, and social distancing top the list, but we also need to monitor our body temperature, and many users wonder if there is a thermometer app worth installing. Using a smartphone to check if you have a fever would be the ultimate convenience, but... it's not that simple.
Body Thermometer Apps? It's Complicated
Why? Because you cannot trust readings from any smartphone sensor when you have a SoC, memory modules, battery, and a display heating up its insides. The margin of error would be too large when the goal is to get an accurate temperature reading, with tenths of degrees Celsius.
Everything I've seen in body thermometer apps falls into three categories: Fake, logging only, or dependent on an external sensor. For example, Body Temperature App For Fever, compatible with iOS, clearly states in its disclaimer that "you must connect your smart Bluetooth thermometer" to record your temperature. Other sites point to iCelsius, but besides needing a probe, its main use is as a cooking thermometer.
Ambient Thermometer Apps? 'Yes'
As long as we are willing to bend the rules a bit on the definition of 'thermometer'. Again, any reading from an internal sensor will be incorrect, and most "ambient thermometers" are actually weather apps that use geolocation to get a weather report.
Some apps do this job better than others. One that has gained some popularity is Thermometer++. The first time you run it, it will ask for permission to access your location (confirming that 'no' it's not a real thermometer), and it will show the occasional ad in its interface, but it works pretty well. You can also configure another location if you want.
The Future? Smartphones with Built-in Thermometers
Beyond the technical difficulties, we cannot deny that user demand exists, and some manufacturers are already exploring the possibility of integrating real thermometers into their mobile devices. Who tops the list? Huawei, of course.
The Honor Play 4 Pro, presented in mid-2020, has an integrated infrared temperature sensor in the rear camera, with a range of -20 to 100 degrees Celsius. It's not ideal, but it's accurate enough to detect if a person has a fever.
In Summary
Use real hardware, and talk to a doctor if you don't feel well. Set aside any thermometer app and get a real thermometer. We appreciate everything smartphones can do today, but when it comes to your health, don't leave it to an app. Good luck!
