I am looking for a device to control lighting. Read great article a few months back in MR about using colored lights (xmas tree). I want to be able to use the computer to control intensity. So far I've looked for commercial products with little success. Am beginning to look for hobby projects that could do what I think I want. Simplest computer interface would USB, but could be 422 or others. Output voltage should vary from 0-120. At first I was thinking it would have to be AC current, but the lights don't care. Could be DC. Anybody have any ideas?
A G-scale DCC decoder's motor drive output could be used to control lights, but not AC voltages and nothing above 20 Volts, which is the usual maximum track voltage for G.
Controlling 120 Volts AC will require a very expensive variac and related circuitry. I'd also check into a light dimmer switch like those used on household lights and available at most home improvement stores. But computer control would be tricky and very expensive.
If you are going to program and build it yourself, the easiest interface to work with is a parallel port. It has lots of output pins, some input pins, and doesn't require any decoder chips. Only some relays or power regulators.
Are you trying to hook it up to certain program? Depending on the software, you can get vendor specific hardware that would do what you want.