Getting started with Arduino and Raspberry pi

Really clever people have turned these components into the open Arduino and Raspberry Pi platforms which can be used or extended to create projects powered by micro-controllers or even full Linux based software solutions.
It is because of these platforms I have been able to create my own Internet of Things devices at home and have had a great time doing it. It was fun but there was a fairly large learning curve that would be even larger for those not familiar with these technologies.
With this particular revelation I decided to create a small guide that would provide a starting point for my boys. This way they could experience the excitement of creating their own projects and to use computers for something other than just playing video games.
This "guide" eventually morphed into something more comprehensive as well as providing more background information. The goal is to have a single source which can be used to provide a proper start to anyone who is interested in creating their own electronic or IoT device or to get a start using open source software.