⚠️ Check out my newer ECG designs:
I followed-through on yesterday's post and actually tried to build an ECG machine. I had a very small amount of time to work on it, so instead of building the fancy circuit (with 6 band-pass filtered op-amps and diodes posted in the previous entry) I built the most crude circuit that would theoretically work.
I used just one of the 4 available op-amps from a LM324. I built this, hooked it up to my sound card, and made electrodes by soldering wires to pennies. After a good lick, I attached the pennies to my chest with tape and tried recording. Every time the pennies made contact with my skin, I would see noise on the trace, but I couldn't seem to isolate a strong heartbeat signal. This is what I saw and the circuit I build to see it:
Perhaps this project will be working soon. Many techno-savvy people have made these DIY ECG machines, but not many describe how to interpret the data. Since I'm planning on building it, testing it, recording ECG data, and processing/analyzing it, I'll may have something unique on the internet.