Phone stethoscope — Yoseph Bagighni

Cardiology · audio signal processing

Your phone is a stethoscope

Press your phone's microphone against your chest. The page filters out everything except the low thumps of your heart valves closing, finds the two heart sounds doctors listen for (S1, "lub", and S2, "dub"), and measures your heart rate from them.

A demo, not a medical device. Phone microphones aren't made for this, and some phones filter out low sounds. It can't detect murmurs or diagnose anything.

1 · Use your phoneOpen this page on your phone. The microphone is the little hole on the bottom edge.

2 · Press it to your chestBottom edge flat against bare skin, just left of the breastbone, about a hand's width below the collarbone.

3 · Stay quiet and stillHold your breath for a few seconds or breathe very slowly. Talking and moving drown out the heart.

heart sounds · last 4 s · 25–200 Hz

Press Start listening with the phone on your chest,
or play the demo heartbeat.

energy envelope · S1 / S2

♥—bpm

Not listening.

Signal lock—

Beat length—

S1 → S2—

Beats seen—

Listen through headphones Use headphones. Through the phone's speaker the sound loops back into the mic and squeals.

See how it worksFour steps, one at a time

Tested on simulated heart sounds from 50 to 140 bpm with added noise and mains hum: heart rate within about 1 bpm. Real phones vary a lot. iPhones and some Android phones apply their own processing to the microphone, which can weaken the heart sounds.