[mythtvnz] [OT] Home Automation

[yuri]

On 20 August 2013 11:24, Steve Hodge wrote:
> Nick wanted dimming, but Yuri was just after relay control. He didn't say if
> he was looking to switch mains power or not, but that would be the most
> common case I'd guess.

I would never hook up a computer-controlled relay board directly to
mains, even if it was rated for it.
I would have contactors with ELV (12V or 24V) coils rated for mains switching.
The problem is not only the voltage, but switching large currents, eg
floodlights, heaters, etc.
The other thing I'm interest in is switching on solenoid valves on a
central heating/radiator system.

For Nick's project, I wonder if a step motor connected mechanically to
an actual dimmer knob would be too error prone? Personally I don't
like moving parts where they can be avoided.
If you only want 2 or 3 dimmer settings it could be reduced to an
on/off problem. Perhaps with 12V halogen lights and some banks of
resistors switched in and out of the circuit?
Not efficient, powerwise, but with only 12V the risk of harm is reduced.

Yuri