Sounds like you are in a similar boat to me. I love to make my own things, and then hook them into the "commercial" stuff to get it tied into the main controller.
My last thing, that I have not finished writing up...even though someone requested it on the Homeseer Forums...I just named last night P.A.W.S. - Portable Automated Watering System. It gives you 4 zones of watering control. It will eventually sit on a cart (if I can convince my wife), which will contain 2 hoses on reels (100' each), 1 100' of hose (2x50'), coiled on top, 1 50' roll, coiled. It will also have the control box, and finally a basket of "stuff" (Various sprinklers, hose ends, tri-pods). I'd like to also put in some kind of manual override...but that is not in the design right now.
The control box has a 75' extension cord, plugged into a Z-Wave module. This controls the power going INTO the box. Inside the box, this powers a GFCI plug (just in case it gets plugged into an outside plug that is NOT GFCI). Plugged into that is a 5V supply and a 24VAC supply (2A). The 5V powers a RF controlled relay board I got on E-bay pretty cheap (~$10 shipped). The relay board only allows 1 relay on at a time. To turn off all Zones, power to the BOX must be CUT. This was intentional, as this was the ONLY relay board at this price that would only power 1 zone at a time BY design.
RIGHT NOW, the 24VAC passes THROUGH the relay board on the NC side of the relay. This also further ensures that ONLY one relay can be on at a time, since the opening of one relay cuts all "downstream" relays...or at least makes me feel better since it also saved me from buying something to distribute the power. I still need to add a fuse to the channels - but I'm not done with this, it's in beta stages (did "alpha" last year).
I still have to do the cart, fuses, add 1 more valve and a backflow valve-thingy (yeah technical). The extra valve will tie directly to the 24VAC. My hope is it is since it is an ORBIT valve, it is FAST off. The other valves are Toro - got them cheap on e-bay (~$25shipped for 4 of them). If the Orbit valve is FAST, this will allow me to shutdown the system by cutting power to the control box. Which the HOPE is that the spiggot is cut first, allowing pressure to LEAVE the system and not keep it pressurized all night / day while waiting for the next run. If that is not the case, I need to add another relay or something. The easiest thing is to add a UPB appliance module hacked into a RELAY module. BUT, I'm trying to make this box non-automation tied. Can probably get a SINGLE RF relay module on e-bay...heck, maybe just get another of the same thing that I have, except at 433Mhz, instead of the 315Mhz that it is at right now. Then I have spare I/O in the box...
All of this is then tied together with something that can be controlled by an arduino, or as I have it right now, tied into an array of serial ports, where I use software in my automation package (Homeseer) to dingle the DTR and RTC (??) to tickle optically isolate transitors which powers relays (this was something I got on e-bay, 8 optically isolated relays in a nice package for an Arduino for $8 shipped), which then finally "pushes" the button on the RF remote for the PAWS.
So far it works very well. Once this is done, you should only need to plug the Arduino into a USB port on your server and control it through serial commands (virtual serial port). On the other side, roll the cart out. Grab the sprinklers and distribute them. Plug the main valve into the hose spiggot. Plug the AC into power. Then hit "go" on the sprinkler package to drive the serial (I use Stevea's Sprinkler package to organize the schedule http://forums.homeseer.com/showthread.php?t=127509).
--Dan
