Scott Harden, at The Blogging Rotagonist, has tinkered together a dual lead ECG system using a basic PC computer and its sound card as the signal processing system and one cent pennies as the leads. All the minutia of the project is amply documented on his blog for anyone wishing to put together an ECG system.
Although several DIY ECG guides exist on the internet, this one focuses on minimizing the part count and cost by performing noise reduction (normally handled by complicated analog circuitry) digitally with your computer. The device hooks up to your chest (using pennies as electrodes) and outputs to the microphone jack of your computer sound card so it can be recorded with free audio software. In addition to a description of how to build and use the DIY ECG, this guide also provides the code needed to perform complicated long-term heart rate and heart rate variability analysis to assess neurological control over cardiac function!
Here’s an overview of the system:
The rest of the details, including schematics and software source code at The Blogging Rotagonist…
Flashback: Get on Board with Open-Source ECG Project
(hat tip: MAKE)