DIY Pulse Oximeter
DIY medical equipment is not a big hobby area but this DIY Pulse Oximeter is one cool device. I have no idea what a commercial Pulse Oximeter but like anything medical the real stuff that is used in hospitals usually costs big bucks. In this case your finger is slipped between two pieces of medical grade oak to take the reading. The project is based around the powerful 68HC908AB32 microcontroller.