[chbot] Wanting to get in touch with Robin (or anyone else who has implemented a controlled irrigation system)
simonches at gmail.com
Thu Aug 12 13:51:56 BST 2010
Seeed Studio sell a cheap($8.50 USD) 12v 19mm OD solenoid valve.
On Thu, Aug 12, 2010 at 10:08 PM, Robin Gilks <robin at gilks.org> wrote:
> > Considering the high cost of "industrial" solenoids + the need for
> > providing
> > and switching 24AC etc, I would seriously consider hacking one of those
> > electronic timer type values that you can buy at any hardware shop. I
> > a
> > two channel unit that I bought from Bunnings for $50 or so.
> > These have a motor + gearing inside that drives the valve open or closed
> > as
> > needed. Works from 3V.
> > This approach would be under powered for irrigation of a large orchard
> > etc,
> > but it would be fine for the smaller set-up. If power fails then they
> > open. However power is probably not a big concern since a couple of AA
> > cells
> > would power this + micro for well over a year.
> Must admit to installing all the valve gear before I thought about
> designing and building my own controller - I just used toggle switches in
> the pump shed for 2 years. That changed because 2 years ago I lost a few
> $$$ worth of walnut trees in a bad frost and the commercial controller I'd
> bought (but hadn't installed) couldn't handle temperature inputs.
> Now I've got all the basics its easy enough to extend so with the current
> code I can set up arbitrary groups (all tunnel houses, all veg plots, all
> treeline drippers etc).
> The biggest problem I had to overcome was being able to select all the
> walnut trees but the pump can only handle 2 sections at a time out of 5 -
> 160 sprinklers at 80l/s. I already only triggered the well pump if the
> demand was high enough (so the veg plots can be watered from the domestic
> pump) so I defined the max delivery from the pump and used an algorithm
> that would maximise its use whilst ensuring that 2 does go into 5 an
> integer number of times. In fact it goes round the 5 sections twice for
> half the time period - took me ages to get the code right!! It can cope
> with any combination now (even 3 or 4 at a time out of 5). The solution
> the code produces is now: (1,2) (3,4) (5,1) (2,3) (4,5)
> This also means that if I set 1 hour of watering the system runs for 2.5
> hours to get round it all. One of the reasons I'm extending the codebase
> to implement statistics!
> Anyone want to buy a very nice unused 12 channel Hunter ICC controller :-)
> Robin Gilks
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