My idea is meant to remedy the serious problem of lack of medical equipment in my home country Kenya and many other third world countries. I got the idea for the project when I lost a friend to a maternal death while at a hospital. Maternal and infant mortality ratios are really high in Kenya.
I plan on using the ubiquitous ATmega328 to implement the Generic USB which can be used in Linux, Mac or Windows without the need for drivers. The ATmega will use some amplifiers to read the analog signals for the ECG and the Pulse Oximeter. I will use a pressure sensor to implement the blood pressure monitor. The BP monitor might use an electric pump or be hand pumped but the values read using the sensor for measurement and storage.
An android tablet with USB OTG(some retail for as low as $50 in Kenya) will be used to display and store the data. The vital signs monitor will be low power and only draw power from the USB.