Dave's Blog

I’m really pleased with a new open-source sprinkler controller I bought. It’s a project of Chris Anderson (who just resigned as editor in chief of Wired magazine) and Ray Wang of Ray’s Hobbies.

It cleanly replaced my old traditional electronic timer controller (12 channels, 24VAC), making it easy to move the wire connections over, and using the existing 24VAC transformer for power. The big virtue of Ray’s controller is that it is network connected, and very versatile. It’s a stand-alone Arduino computer with a small LCD display and a few buttons, with an Ethernet connector that can either connect to your computer system via wire (which I’ve done) or via WiFi (by buying a WiFi access point from whomever).

Now I can see the programs on screen, much easier to check and edit than the old timer system. It’s expandable to 32 channels with little effort, just plug in the expander boxes for groups of 8 channels. In principle it can go even larger, and can be customized in a variety of ways if you like to hack.

Its web interface lets me manually control the sprinklers from my iPhone as I walk around the yard, and I can check on things or change programs from anywhere in the world (I did set up Port Forwarding on my home router, and use a dynamic IP address manager, Dyn.com, to make this happen, but I’d already done that for other purposes so it was little trouble.)

It’s called OpenSprinker, at http://rayshobby.net
For hackers, all the software is available online so you can reprogram it any way you like.

In fact, I expected to do just that. One of the features the system lacked, which I really really wanted, was a log of what watering was actually done over the last week.

But it turned out that Ray designed the system so flexibly that I was able to do everything I wanted just by writing my own web page that kept a log and then formatted it and displayed it the way I liked. I just used PHP and adapted some of Ray’s public JavaScript, and presto–no reprogramming of the Arduino was needed. Nice!

I’ve been very impressed by the quality of Ray’s software and the care he’s put into his hardware design. It’s really great that he’s made these things open source. However, I bought the assembled and tested version, to save time. (I bought the main controller plus one 8-channel expander box, for 16 total.) But it was the open source nature of the system that made me decide to buy it, because that way I know I’m not trapped if I want to make basic changes. It’s so much nicer (and less buggy) than normal commercial products.

Of course, I’ve made my software available too, via Ray’s site.

Someone in Australia already contacted me who has adapted it to his commercial nursery setup!

Update: I had a problem! My wife said the system wasn’t watering part of the garden, and I looked at the logs and said that it was! Eventually I went out to the garden and used my iPhone to turn on the corresponding circuit, and sure enough–no water. So I investigated, and the problem turned out to be that the cable connecting all the sprinkler wiring to the controller had gotten pulled, and about half the circuits were no longer making contact! So, the controller was indeed telling the system to turn on the water, but the wires didn’t carry that info to the valve, so no water arrived.

I fixed the problem by making some little clips that hold the connector onto the controller securely. The better solution for the long run would be to use connectors that have a latching feature.

Of course, this has started a long-term project to measure the moisture in the soil, which could not only detect such failures but could also be useful in figuring out how long one needs to water, which is purely a guess now.

This entry was posted on Saturday, November 3rd, 2012 at 18:08 and is filed under Nice products. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.