4 intermediate maker projects
From the book:
http://shop.oreilly.com/product/0636920031765.do
Make: Raspberry Pi and AVR Projects Augmenting the Pi's ARM with the Atmel ATmega, ICs, and Sensors
By Cefn Hoile, Clare Bowman, Sjoerd Dirk Meijer, Brian Corteil, Lauren Orsini