Hi there,
My first actual project with my Arduino UNO.
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.
Weedpharma
Cat 5 would be 24 or 26 AWG or 3.5 or 2.2 amps. That would handle a 24W solenoid which would be a pretty large valve.
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.
Take a tip from serial, make the OFF state HIGH.
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.
Thanks everyone for the support,
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)
Here is a link to my exact solenoid valve: http://www.sparkfun.com/products/10456
I'm new to everything and you all slightly confused me so I drew up what I have, let me know your suggestions before I fry something on my board.
Blue = CAT5 cable to arduino
Black = GND
Red = Power
NOTE: Solenoid is different in image.
I would connect the valve with power and a relay together into a package that could turn on or off with a switch.
Then I would substitute the switch for something low power to the Arduino like an opto-isolator or shift register.
yep just fine what you made and repeat it.
you can with shielded cable control 8 valves.
with utp only 7
as all gnd can be tied together.
GoForSmoke:
I would connect the valve with power and a relay together into a package that could turn on or off with a switch.Then I would substitute the switch for something low power to the Arduino like an opto-isolator or shift register.
Hi GoForSmoke, cloud you explain a bit more?
I did a bit of googling and your idea may sound more of what I need for my final project beyond the breadboard.
Can you make the valve work without Arduino, control by pressing buttons or switches by hand?
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.
