Build Your Own ECG-EKG Unit | Nuts & Volts Magazine
How to Build an Electrocardiogram Machine (EKG) | PCB | Maker Pro
simple & cheap ECG with arduino / EKG mit Arduino - YouTube
Electrocardiography for Cheap: DIY ECG Uses One LM741 Op-Amp, Five Resistors, and 'Penny Electrodes' « Adafruit Industries – Makers, hackers, artists, designers and engineers!
Check Your Heart Condition Under 10$ || DIY Homemade ECG Machine using AD8232 - YouTube