I've searched around for schematics on how to circuit 1 solenoid using a MOSFET. I'm assuming for any others maybe up to 10+ I would duplicate the circuitry using a different pin.
My question is,
How do I control the solenoids at a distance? (30Ft or so.)
I would love it if i could use Cat5 or a similar ethernet cable as they are low cost and have many wires.
I'd expect cat5 cable to work fine for that - the gate doesn't need to carry any significant current. Just observe all the usual concerns of mosfets (ie, the pulldown on the gate) and inductive loads like solonoids (clamping diode across the coil to clamp the back EMF), and it should work fine.
Are you proposing to simply control or power the valves at 30'?
If you are wanting to send the control to the MOSFET at the valve using power at the valve then no problem.
If you want to switch the valve by sending the actual valve voltage, you may have problems due to current draw. This of course depends on the valves used.
Shielded cable seems a must, especially if you put FETs at the ends.
It would be better to use your thin wires for signal and a heavier pair for power or even draw upon power at the valve. Opto-isolators can simplify life there.
Solenoids are not all born equal. The current they draw is almost always more than the capabilities of the output of an arduino pin, so your use of mosfets is quite valid.
However, the actual power they consume varies enormously. Some could be powered through cat5 while others would require something more akin to a crowbar. I suggest you get some idea of the current anticipated from your solenoids.
yes use the pins as you found out. you can put a 575 shift close to the valve so you only need 3 wires to your valve box
use a serial signal (onewire)
or put the arduino near the valve box.
I plan on using the CAT5 cable only to control the valve (blue wires). Each group of valves would be connected to their own 12V power source. (via AC power adapter)
I could however the end scope for my project is for a stage show where I would have things timed together in sequences. eventually wanting to add pressure sensors, water level sensors and LED lights for effects.
When you have the valve working at a button press then you replace the button with something that the Arduino can switch easily and safely at 30 feet. Try to keep the power part separated from the control part.