I used to read a lot of Amiga Shoppers. A lot of their coverdisks also had tutorials.
Automation and messing with the hardware is nice.
Programming the serial and parallel ports (the first choice I remember for automation) on the Amiga is easy. Last time I dit it, I used assembly, but I didn't have a hard drive to confortably use a C compiler.
There's a program of mine on Aminet which uses the serial port (orion.lzh). I actually did a faster version using the parallel port but lost the code.