huggy,
Do you a pinout for the serial port? I have few serial and parallel cables that are not in use anymore. Can you draw a diagram of that approach. It looks very interesting.
Thanks!
I don't think you want to go there. It's isn't hard if you're comfortable with electronics...but there are several considerations. You will have to built a driver circuit and develop a custom application of some sort to tie the parallel port into whatever HA app you may use. Yes there are samples of each to help you along the way, but knowledge is power here. You can easily damage a parallel or serial port, or even the entire motherboard if something goes wrong. Stick with the ELK or X10 route mentioned earlier. Also, some PCs pulse the pins on the parallel port during POST. That could wreak havoc with whatever you're controlling, not to mention be potentially dangerous if your PC reboots at the wrong time. Again, yes there are ways around these problems as many (myself included) use the parallel port for control/monitoring, but you'll need a decent understanding of how the I/O ports operate, and how to communicate with them. I'm not trying to discourage you, but this could quickly turn from a "poor mans sprinkler controller" to something way more expensive if a motherboard gets toasted.
If you want to learn more about controlling devices with a parallel/game/serial port; there are a ton of resources on the 'net. A good place to start is
here.
Terry