Through my interest for the human body and the access to osciloscopes I found myself sitting in a laboratory trying to measure my heart rhythm with a simple osciloscope. That didn’t work out, so I made a project out of it. The result is not only one working ECG, but both a mobile device and a full 12-lead ECG. The accuracy in the time domain is pretty amazing, since it uses audio-channels with a good time resolution. In the current domain (the shape of the peaks) is not yet tested with certificated equipment.
Also the project got me involved with the Quantified Self movement and a short section in the book “Det man måler er man selv” (ISBN: 9788702143195) by Anders Høeg Nissen, radio journalist for the Danish national broadcaster (DR).
This project uses a modified version of the curcuit described by Jason Nguyen from the University of Utah. Check out his project page