Talk about hardcore homebrew. There's a guy who calls himself Refik and he's gone and done what we thought seems insane, yet fully plausible: he's made his very own electrocardiograph, or heart monitor.

Now, according to his explanation, he's also made something that could potentially kill you because of the electricity involved. He writes,

Before I continue to explain what I did, I would like to WARN you! 500mA (miliAmps) on 220V will completely destroy your nervous system (so run it from battery supply), check everything twice and you are responsible for it on you own.

The fact that he survived using it on himself is testament to his engineering abilities, though we're definitely hesitant to praise him for showing the schematics off for public use. Someone's bound to take a chance and screw this up. Still, snaps to him for pulling it off without dying of electric shock.