Electrocardiography for Cheap: DIY ECG Uses One LM741 Op-Amp, Five Resistors, and 'Penny Electrodes' « Adafruit Industries – Makers, hackers, artists, designers and engineers!
DIY ECG circuit - CircuitLab
The Do-It-Yourself Electrocardiogram | SpringerLink
DIY ECG Using an Analog Discovery 2 and LabVIEW – Digilent Blog
Electrocardiography for Cheap: DIY ECG Uses One LM741 Op-Amp, Five Resistors, and 'Penny Electrodes' « Adafruit Industries – Makers, hackers, artists, designers and engineers!