I understand that I can build a circuit that will do whatever I like (ex: a simple circuit that will turn on a motor to open the blinds or something), and I can write a program that will automate my computer/mac however I like (ex: open this program at this time, or with this input and create a new file, ect).
My question is, how can I interface the two? Is there an easy DIY or cheap commercial (or not cheap but functional) USB plug that will turn on/off from computer commands? I'm basically looking for some sort of on/off switch I can script/applescript. How would you even approach this problem, would I have to write my own driver some where along the way?