How Heart rate Sensors measure pulse?
If you try to cover a flashlight with your palm you’ll see a red glowing effect. This is because some part of the light is able to pass through your skin. The heart rate sensors on the smart devices and fitness trackers take advantage of such light. It flashes a bright light on your skin so that it penetrates your skin and is reflected by the blood flowing through it. A sensor captures the image and processes it to calculate your heart rate. Read: Turn Off Heart Rate Monitor on Apple Watch, Galaxy Watch, and Mi Band
Developers are a creative bunch and when they realized that smartphones have decent specs and processing power to compute the algorithms, they developed an app that just uses the flash and the camera sensor to calculate the pulse. At first, I thought it was just a gimmick but testing it simultaneously with smart watches, and fitness trackers I’ve come to the conclusion that these apps work just as good.
Heart Rate Monitor App on Android
There are plenty of apps on the Play Store which would get you good enough results and I would go out on a limb to say that most of the apps are just fine, not special. The only key difference is the additional features and a slight change in the calculation of the pulse. Accurate Heart Rate Monitor is a minimal app that lets you measure pulse using the camera and the smartphone flash. The app can support Google Fit and sends your stats to the app for in-depth analysis. The app is not as fast as the fitness trackers but it does give consistent results. You can, however, change the measurement time in the settings but that might yield inconsistent results.
To measure your heart rate using the app, install and grant Camera access so that it can turn on the Flashlight and record the image. The app keeps the Camera ON in the app and automatically start measuring as soon as you put your finger on the camera Sensor. Just make sure to put your finger directly above the camera sensor and the flash for accurate results.
I really like the thought put behind this feature and you don’t have to tap any button to manually start recording. You can label every pulse and store it as a stat in the app or ignore to delete the value. You can also check the history to see the performance. It shows a minimum, maximum, and average heart rate along with the weekly graph which would give you enough data for an in-depth analysis. The app also lets you export the data as a CSV file which is an added bonus. Measure Heart Rate with Accurate Heart Rate Monitor (Android)
Heart Rate Monitor App on iOS
iOS may have restrictions on the hardware but the apps are just as good as the Android apps if not more. Apple does have its own Smartwatch that has a heart rate monitor. While you can always buy an Apple Watch but if you have an iPhone with a working flash, an app would do just fine. Instant Heart Rate: HR monitor works just like the Android app and calculates the pulse by shining a light through your finger. It asks you to create an account before you can take a measurement so you can either create an account or sign in using your existing social media accounts. After the setup, just tap the measure button on the bottom to begin measuring your heart rate. Place your finger on the Camera and make sure to cover both the sensor and the flash for maximum accuracy.
The app quickly measures the pulse and generally shows your heart rate in under ten seconds. The accuracy depends on a few external factors like how still you were while measuring, how much the sensor was covered, etc. Read: Apple Watch v Galaxy Watch: An In-Depth comparison
The app offers many features apart from heart rate measurement. The App logs all the measurements in the app which you can check in the insights tab. Generate a report including PPG graphs which can come in handy if you’re going to visit the doctor. You’ll have to pay for those extra features with a subscription plan for $30/ year. If you just want to measure heart rate once in a while and keep using the free version, it would give you no problems, just ads. Measure Pulse with Instant Heart Rate Monitor (Android | iOS)
Comparison between Apps and Smartwatch
I can’t vouch for any of these apps without testing so I compared the values with actual smartwatches. The devices can detect the heart rate using actual monitoring hardware. So, I set up this test where I wore an Apple Watch and Galaxy Watch on each hand. And for the apps, I placed each of my index fingers on the Camera and Flash of an Android phone and an iPhone. These were the results. Read: Best Galaxy Watch Apps
Check Heart rate on Android and iPhone
These were the best two apps which I tested to measure the heart rate with just a smartphone. While the results are fairly consistent with a little margin of error, I should also warn you about the high intensity of these flashes. The flash on smartphones today are extremely bright and can actually cause discomfort and also pose a risk to your flash LED if used for longer durations. The readings can fluctuate if you don’t position the finger correctly or move while measuring the pulse. You must take into account that these apps are good for general use and should not be substituted with an actual medical examination. What are your uses and how do these apps help you?, Let me know in the comments below.
