Re: USB controlled mains switch

In message <TjgqpoLGRDjnFwvW@ku.gro.lloiff>
          Adrian <bulleid@ku.gro.lioff> wrote:

I'm looking for a USB controlled mains switch (230V AC) that I can  connect
to a PI to turn a mains power supply on and off.
 
I've done a bit of digging around on the net, and the options seem to  fall
into two categories, either a relay device which means having to  rewire
the device (which I'd rather avoid), priced around 30Euros or one  that
sits in line (between the device and the supply).  The latter  appears to
be in excess of 100Euros, which is considerably more than I  want to pay.
 
Any suggestions on where to look ?  I'm not interested in a wireless
solution, as it is likely to be used in places where signals are not
reliable.

I did a bit of searching around.  AliExpress sell various models of
USB mains-rated relay boards.  Various models offer 5V, 12V or 24V
operation.  I see from a later posting that your RPi is in an IP55
plastic box, so I'm jumping to the conclusion that you're happy with
a bit of DIY to turn it from a board into a solution.

If I were doing it this way, I think I'd go for a 12V powered board
and have a separate PSU, rather than burden the RPi's supply further
as many people have problems that are traceable to inadequate power
supplies.

It sounds like you may have to build a USB library for the relay
boards - I don't know.

If I were doing the overall job that you're doing, I wouldn't use
USB, I'd use a GPIO pin to switch a different relay board on/off.
Much easier (and I've done lots of work on USB firmware and drivers).

David