Howdy,

> One thing though. Dale Farnsworth responded to my post and then emailed me
> saying he heard that 24vac solenoids in most sprinkler valves can be
> actuated with 12vdc. Can you confirm that? That would certainly simplify
> things.

It would make sense that they would be usable with DC, though you may find 
they get hotter (not sure if the water would cool them a bit).

As for control though, I'd recommend looking into SSR (Solid State Relay). 
You can directly connect them to a PIC output (they present themselves as a 
simple LED to the PIC) and they are opto-isolated and can switch large loads. 
  Unlike a relay, they don't produce a spike when opened and the can control 
AC easily -- which is probably the more ideal choice given it's likely the 
current supply for the valves is AC.  Their control is a simple on/off for the 
PIC I/O pin.

I've used them for my sprinkler project as well as a few HVAC controllers (for 
ducts, blowers and tstat control) and have found them incredibly easy to use 
and very flexible.

Gerry
-- 
Gerry Duprey
Ann Arbor, MI 48103
http://www.cdp1802.org
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