Your heart is constantly work for you, yet you think nothing of it—and Samsung wants to change that. They stuck a dedicated heart-rate monitor on the Galaxy S5, they’re putting one in the upcoming Note 4, and they’re bound to slap one in every Galaxy device thereafter.

While the Galaxy Note 3 doesn’t share this feature, my daily running routine makes me really wish it had. Just being able to quickly press my finger on the back of my phone to get a reading of my pulse would be extremely useful when I’m working out.

I don’t plan on trading in my Note 3 just yet, so until it’s upgrade time, there’s something else that can be done. Use the camera. Yes, you heard that right. With some ingenious trickery, the camera on the Note 3 can be used to measure your pulse, and here’s how you get it done.

How Does This Work?

Using the rear-facing camera on your device, you can use an app that measures changes in the color beneath your index finger. If this sounds too good to be true without special equipment, it’s not. Medical pulse oximeters use the same technique to measure pulse.

Step 1: Installing Instant Heart Rate

Tap here to download Instant Heart Rate, by developer Azumio, from the Google Play Store. Azumio also has apps for iOS and Windows Phone users, so pretty much any smartphone can be used with a rear-facing camera and a good flash (though, a sunny day is enough to get a good reading).

Step 2: Using Instant Heart Rate

Begin by launching Instant Heart Rate from your app drawer and going through a brief tutorial. Next, just press your index finger onto the back camera and let the app take a reading.

I measured my own pulse manually and found Instant Heart Rate to be spot on. To make sure this wasn’t a fluke, I placed my Note 3 onto my table and let the app read for a pulse—as I was hoping, it flatlined, so no placebo results here.

Additionally, you can make an Azumio account to store your heart rate readings so that they’re synced across multiple devices. So, now you have yet another great use for your Note 3—this thing just gets better and better.

The free version of Instant Heart Rate does contain ads, and only lets you store 5 measurements in your timeline, but the Pro version ($1.99) fixes both of those issues, if you want it to.