sprinkler valves

[justDIY]

i bought a sprinkler valve to experiment with this weekend, it was on sale pretty cheap, so I thought what the heck.

the valve is pretty big, and must be operated by water pressure or a spring loaded diaphram?  There is a tiny soleniod on the valve that opens and closes a tiny hole in the body of the valve

anyway, to the point of my question:
the valve claims it works with 'most 24 volt ac sprinkler systems' ... well, I have 12 volts DC (same voltage that runs my mini pump), so I tried it out... the solenoid actuates just fine - but I wonder about the AC vs DC part ... is the solenoid going to overheat since the DC basicly jams it open with one polarity, instead of an alternating field like AC would give it?

I didnt have the right bits and pieces in the plumbing box to hook the valve up to my garden hose, so that'll wait for tuesday... to see if 12vdc can actually work the valve - I'm also wondering if my mini pump can operate the valve either, it only has about 10 psi of head pressure, far from the 40-80 of 'city' water

[Rob]

Were you asking becuse you are planning on making a DIY timer using 12VDC, and thus operating it long term that way?

I'm not 100% confident in this answer (maybe 90%), but I believe an AC solenoid is just one that includes a rectifier--so you're dropping a volt and a half when you power it from DC, but otherwise no harm no foul.  I'd be tempted to use my 12V to switch a 24VAC transformer on/off, just to stay most compatible with other cool equipment as you grow the system. 24V xformers aren't hard to scrounge, either.

Do you get this catalog?

[justDIY]

Do you get this catalog?

well....  mouser, newark, bgmicro, all electronics, jameco, allied, graybar, grainger, dr foster smith, pet supplies plus, and whatever else stuff my mailbox monthly, whats one more right?  thanks for the link 

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good point about using the 12v to control a separate power supply for the solenoid - primarly I'm just trying to keep the # of components down

a quick couple pokes with the mutlimeter should determine if there's a diode involved in the unit I have.

as for a timer, jeeze dont get me started, I have enough half-baked projects already on the board ... I was planning on just using a programmable lamp timer to turn the power supply running the pump and valve on for 15 min every 4hours or so... but now that you mention it, something with a microcontroller, lcd readout, maybe a rain guage, 'cloudy day' sensor and soil moisture probe would be more fitting!

[Rob]

Surplus Center + you = ♥♥♥

Let me know when you release sprinklerOS 1.0.

[tbone]

OK, here's my plan...

I wrote an application that runs on Windows.  My PC is the "brains" and when it's time to water the grass, it will establish a Bluetooth connection to a remote device (then there are no wires running to my PC from my yard).  The remote device will enable a solenoid!

Here's a screenshot of my app...



I stumbled upon this thread looking into DC solenoids as the power supply I have to control this is DC.  Tomorrow I want to pick up a 24VAC solenoid and take it apart to see if I can use it.

What do you guys think?

[Rob]

Awesome. I'd think it would be a whole lot easier to stay DC all the way though. What would you use to power the remote? Should I take "no wires" to also include power?

[tbone]

Awesome. I'd think it would be a whole lot easier to stay DC all the way though. What would you use to power the remote? Should I take "no wires" to also include power?

The remote device will plug into the wall in my garage (which is close to where the solenoid needs to be mounted).

The remote device is actually a Rockford 3Sixty



I'm an EE @ Rockford and this is my baby, I have some old protos laying around that I will just reprogram 

[justDIY]

my Orbit 24vac valve worked fine under test conditions using 12vdc ... test conditions being a car battery and a garden hose.

I don't know if the 24v makes the solenoid open faster or what, and the AC doesn't seem to make a difference.  on the other hand, when I put the valve "into service" controlling the supply for my water filter, I did use a 24vac supply (which also powers my water filter boost pump) ...  I didn't want the additional variable a non-compliant power supply would present.  That's been many moons ago, and everything is well.

typically, the valves are located on a maniflod near the house, and the zones are connected with hose - I recommend running 24vac to your manifold box, and you can toss a rectifier and voltage regulator on there to get your 12vdc for the gizmo

I looked up that 360, it seems like some major overkill for controlling a few zone valves, but I suppose, if it's free, why not!  What kind of range to you expect to get connectivity over?   I seem to recall bluetooth is severely limited in its power output, and I don't see an external antenna on that device.

[tbone]

The range is 10m.  And yes, the antenna is inside on the PCB.  The range is achievable thanks to the plastic endcaps on the device.  My device is not waterproof so it will remain inside my garage.  Wires will run from the solenoid 10 feet or so into my garage where my device will get its power from.  My officePC is located on the other side of the wall so the line of sight distance (for 2.4GHz) is only around 10 feet.

I could make a dedicated PCB but the Bluetooth IC is in a BGA package.  It's much easier to use an exisiting PCB with the Bluetooth already connected and just reprogram the uC.