I have a home project that I currently have it running on the parallel port.
I have two buttons (for input) that send their on/off status on the parallel port (paper out and busy if I recall correctly, it doesn't really matter) and I have some scripts (mainly call parashell) that will send 5V on other pins of the parallel port if some conditions apply.
As the parallel port will no longer be an option I'd like to get a simple USB controller that can do these tasks. It must have linux drivers.
The idea will be the same. If a button (or two) will be pressed, send a 5V on two wires.
the 5V is not mandatory as the 5V is actually triggering a relay that will close a circuit (effectively pressing a third button).
Please let me know if I haven't described the scenario properly or if you don't fully understand what I'm trying to achieve.
The real life application is quite simple. I have an on/off microswitch attached to the garage door and a PIR in the garage. If the microswitch is open (the garage door is open) too long, send an email: "Hey, you forgot to close the garage door!".
A different scenario is: if the microswitch is closed (garage door closed) and the PIR detects movement then send an email: "Hey, the cat sneaked in the garage again and it's now trapped inside!".
The 5V (output) is to trigger a relay that will open or close the garage door remotely. It can be either 5V triggering a relay or just short-circuiting two wires to close the circuit.
I can find my way around with the soldering iron but I only have basic electronic knowledge. Is there something readily available or something that can be assembled on jaycar or mindkits?
Many thanks in advance.