The Samsung Galaxy S5 will come with a heart rate monitor built-in, but iPhone users can now 3D print their own heart rate monitor add-on.

Heart rate measuring apps that use the iPhone's camera and light are already available, but this stethoscope is a brilliant alternative. It was designed and 3D printed by a 15-year old after his generous parents bought him a MakerBot Replicator 2.

The Stealth IO is a plastic iPhone case that doubles as a stethoscope. The case uses a diaphragm that collects low-frequency sounds and delivers them through a tube to the microphone. The app then "hears" the sound of a person's heart beat, displaying it on the screen.

iphone stealth io heart rate monitor was 3d printed by a 15 year old image 2

The creator Suman Mulumundi, whose father is a cardiologist, has started his own company called StratoScientific and has applied for the patents for his design.

When the design gets FDA approved it may become available to download and print but from the look of the StratoScientific website, it won't come for free.

READ: 3D printing: Everything you need to know and when it'll be affordable