iStethoscope Free 4.0

Normally we discard apps that claim to see ghosts, read brainwaves, or take your pulse. But some of these apps simply rely on the iPhone’s built-in sensors, and sometimes, they really work.

Undercover scientist software offers this app called iStethoscope Free which Apple recklessly inserted in the Medical section of the App Store, despite being nothing but a fun (and very unreliable) tool. We're filing this one under "Fun."

A real stethoscope in your pocket

iStethoscope Free is an app from the days of iOS 4, and has been left that way since 2010. It doesn’t even support the iPhone 5’s 4-inch display, let alone bigger screens, but it still works even on the newest devices with the newest firmwares.

It comes with a huge disclaimer about how it’s intended for entertainment purposes and that it shouldn’t be relied upon for “the diagnosis of disease or other conditions, or the cure, mitigation, treatment, or prevention of disease and should not be used as a medical device.”

It actually works (once in a blue moon)

Yes, it actually does work. Half way through our testing we were getting only background noise, and then we decided to visit the description one more time to see if we’d missed anything. Sure enough, we had. According to developer undercover scientist software, you need to place the microphone directly against the skin, not through a shirt, and press the phone’s bottom mic to the chest in the apex of the heart (below the left nipple). The heart-beat waveform suddenly started to appear.

Not very intuitive

To be frank, the app is a real pain in the neck. You have to be really precise about the placement of the mic on your chest, and you need to select the proper audio filter (mode) to allow it to set apart background noise from your heartbeats. Your best bet is likely to be the Heartbeat Filtered mode. Don’t give up if you don’t see results after your first couple of attempts. You’ll eventually get there. It worked for us, so it should work for you too