The MobilECG Business Card, A Tiny Portable Heart Monitor That Fits in a Wallet
The MobilECG business card is a tiny portable heart monitor that fits in a wallet. It was created by the same team behind the MobilECG, an open source and affordable heart monitor. They stress that the business card is not a diagnostic device, but it is also open source. The repository is freely available on Github, and a PDF of the schematics is available as well.