The Step_X (Stephen's Experimenter) board. complete (at the moment) with some annotation to indicate major areas. The concept is to have one place to gather some simple I/O tools addressed by the Raaspberry Pi GPIO, which is further protected and buffered by zener diodes and a series of OCL darlington drivers to 'push' more from the GPIO. No ADC on board but easily added. You can make one as well.