Scott Harden has designed an ECG/pulse oximeter combo project using LM324 op-amps. Scott describes, “This new project is fully documented and uses extremely common and cheap parts, all of which could be purchased at RadioShack. It serves as both an ECG *and* a pulse oximeter, depending on which leads are attached. It uses a single chip (LM324, a quad operational amplifier) with a virtual ground to eliminate the need for a negative voltage. As a pulse oximeter with a 12V supply it outputs clean 10V swings when pulses occur. It’s intentionally unsophisticated, and made to be easy to replicate by anyone interested in electronics. Although you could view its output on an oscilloscope, it’s designed to be output into a PC sound card for recording (if attenuated to microphone levels). I even describe how to spectrally process the data on the computer to clean it up, downsample it, and graph it in Excel or with a Python script.”
Visit Scott’s website for project details, schematic code and more video.
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