<meta http-equiv="content-type" content="text/html; charset=utf-8"><span class="Apple-style-span" style="font-family: arial, sans-serif; font-size: 13px; border-collapse: collapse; ">Seeed Studio sell a cheap($8.50 USD) 12v 19mm OD solenoid valve.<div>
<br></div><div><a href="http://www.seeedstudio.com/depot/electric-solenoid-valve-p-636.html" target="_blank" style="color: rgb(6, 88, 181); ">http://www.seeedstudio.com/depot/electric-solenoid-valve-p-636.html</a></div><div>
<br></div><div><font color="#888888"><a href="http://www.seeedstudio.com/depot/electric-solenoid-valve-p-636.html" target="_blank" style="color: rgb(6, 88, 181); "></a>Simon Chester</font><div></div></div></span><br><div class="gmail_quote">
On Thu, Aug 12, 2010 at 10:08 PM, Robin Gilks <span dir="ltr"><<a href="mailto:robin@gilks.org">robin@gilks.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div class="im"><br>
> Considering the high cost of "industrial" solenoids + the need for<br>
> providing<br>
> and switching 24AC etc, I would seriously consider hacking one of those<br>
> electronic timer type values that you can buy at any hardware shop. I have<br>
> a<br>
> two channel unit that I bought from Bunnings for $50 or so.<br>
><br>
> These have a motor + gearing inside that drives the valve open or closed<br>
> as<br>
> needed. Works from 3V.<br>
><br>
> This approach would be under powered for irrigation of a large orchard<br>
> etc,<br>
> but it would be fine for the smaller set-up. If power fails then they stay<br>
> open. However power is probably not a big concern since a couple of AA<br>
> cells<br>
> would power this + micro for well over a year.<br>
<br>
</div>Must admit to installing all the valve gear before I thought about<br>
designing and building my own controller - I just used toggle switches in<br>
the pump shed for 2 years. That changed because 2 years ago I lost a few<br>
$$$ worth of walnut trees in a bad frost and the commercial controller I'd<br>
bought (but hadn't installed) couldn't handle temperature inputs.<br>
<br>
Now I've got all the basics its easy enough to extend so with the current<br>
code I can set up arbitrary groups (all tunnel houses, all veg plots, all<br>
treeline drippers etc).<br>
<br>
The biggest problem I had to overcome was being able to select all the<br>
walnut trees but the pump can only handle 2 sections at a time out of 5 -<br>
160 sprinklers at 80l/s. I already only triggered the well pump if the<br>
demand was high enough (so the veg plots can be watered from the domestic<br>
pump) so I defined the max delivery from the pump and used an algorithm<br>
that would maximise its use whilst ensuring that 2 does go into 5 an<br>
integer number of times. In fact it goes round the 5 sections twice for<br>
half the time period - took me ages to get the code right!! It can cope<br>
with any combination now (even 3 or 4 at a time out of 5). The solution<br>
the code produces is now: (1,2) (3,4) (5,1) (2,3) (4,5)<br>
<br>
This also means that if I set 1 hour of watering the system runs for 2.5<br>
hours to get round it all. One of the reasons I'm extending the codebase<br>
to implement statistics!<br>
<br>
Anyone want to buy a very nice unused 12 channel Hunter ICC controller :-)<br>
<br>
<br>
--<br>
<font color="#888888">Robin Gilks<br>
</font><div><div></div><div class="h5"><br>
<br>
<br>
<br>
_______________________________________________<br>
Chchrobotics mailing list <a href="mailto:Chchrobotics@lists.linuxnut.co.nz">Chchrobotics@lists.linuxnut.co.nz</a><br>
<a href="http://lists.ourshack.com/mailman/listinfo/chchrobotics" target="_blank">http://lists.ourshack.com/mailman/listinfo/chchrobotics</a><br>
Mail Archives: <a href="http://lists.ourshack.com/pipermail/chchrobotics/" target="_blank">http://lists.ourshack.com/pipermail/chchrobotics/</a><br>
Web site: <a href="http://kiwibots.org" target="_blank">http://kiwibots.org</a><br>
Meetings 3rd Wednesday of each month 6:30pm-9.30pm Science Alive Seminar Room<br>
<br>
When replying, please edit your Subject line to reflect new content.<br>
</div></div></blockquote></div><br>