CowboyRobot writes: When requirements are tight and unforgiving, it's sometimes easier to design your own protocol. The article describes the design considerations for a basic network architecture that could be used as a starting point for a simplified personal area network. This particular network consists of low-power nodes that capture physiological data from sensors and condition it before sending it to a central node for processing. The design considerations include: Does each node need to communicate outside of the closed system? What happens if the communication link for a node is down? Is it catastrophic if a single data sample is lost? Does the data reception need to be acknowledged by the receiver?