Programmable Power Switch

I've been thinking about one of these for a while...need to be able to power off devices programmatically.  Some of the comments are useful.  To wit:

1. You might consider a "zero-crossing" detector however, as switching AC during the high portion of the sine wave will eventually cause your relays to pit, scar, and fail from the internal arcing. By sampling the AC wave and switching the relay on/off only during the zero crossing of the sine wave period - that will make your relay last for years.

2. You should add a base-emitter resistor, something like 10K. If you leave the base unconnected noise(50/60Hz) might turn on the transistor - and the relay. It happened to me a while back while switching some lights with a very similar circuit.

3. Try something like a MOC3043 zero crossing detector optocoupler. If you couple it with a triac you basically get a good switching method, similar to a SSR. Don't forget the snubber for inductive loads.

Need to get my workbench in order....