As for the relay board, get one that has 5V (not 24V) relays on it.
I had assumed that when it said "5V" it was referring to the maximum switch voltage (I believe that's what it's called). I see that I messed that up, I found this 5V relay shield instead http://www.amazon.com/SainSmart-8-CH-8-Channel-Relay-Module/dp/B0057OC5WK that should work, right?
It will probably be easier if you use 12vdc solenoid.
I'm open to using either 24VAC solenoids or 12VDC solenoids, which ever is easier and more efficient to control.
if you have one nozzle, you could get high pressure and high volume.
if you have 10 nozzles, the flow could decrease to be unusable.the end result should be that there is no change on any unit, regardless how many are in use.
If I ditch the idea of the clear water tube filling up, would this still be an issue? As long as there is still enough pressure when all 10 guns are active to knock the target switch, it shouldn't matter. Correct?
There are already digitally controlled hose manifolds for watering your lawn. Buy one of them for $20, open it up, and see what happens on the board when it triggers. Solder in wires and supply the voltages yourself!
That sounds like a good option, but I did a quick Google search and could only find manual hose manifolds. Do you happen to have a link to some digital ones?
When that's closed, it completes a circuit to turn a small DC motor. he motor spins a long threaded rod ("Screw Drive") that you buy at Home Depot for $2. You have a little indicator ride a rail with a nut on the back... As the motor spins, the indicator rises along the screw! Have another feather switch at the top -- first one to hit the switch wins! (and it sets off lights/sounds/closes water gun solenoid/etc)
That sounds like the better option, I had originally thought that driving several motors would be more difficult than simply opening up some solenoid valves.
Sean