Garden Reticulation with Raspberry Pi and OpenSprinkler

So a couple of weeks ago I noticed that my lawn was starting to dry out. We’d only just turned the system back on and I’d gone around and checked that it was all working ok.

I went out to the box and noticed that it was displaying a FUSE message on the screen. Not good.

A quick google search sent me to this article explaining that it is normally a solenoid coil that needs replacing. OK, a cheap part but I can do that.

First I had to identify which solenoid was causing the issue. This was a simple process of disconnecting each in turn to see when the message was caused.

It seemed on every station, so the culprit was likely the master solenoid.

It was easy enough to find, but not so easy to dig out

It was under a rose bush, and full of sand.

A trip to Bunnings was the next step to buy a new solenoid to use for parts (as cheap as buying a new coil on it’s own, Bunnings also don’t stock just the coil and being a Sunday it was my only option).

I replaced the coil, wired it up again and tested everything.

Still tripping with FUSE…

At this point I’d run out of time and available tools to diagnose the issue any further. The following weekend my father-in-law came around armed to the teeth with multi-meter and tools to help find the issue.

Each solenoid was receiving voltage, each was turning on. There was no problem in the wiring, or the coils.

The problem only seemed to occur when both the master solenoid and the zone solenoid were both turned on. The conclusion we came to was that the cheap controller we had installed by the landscapers when the house was build 14 years ago wasn’t coping with 2 open solenoids.

The temporary work around was to disconnect and manually open the master solenoid and leave the zones as is so that only 1 needed to be opened at a time. It worked!

It worked as a workaround. I wasn’t happy with keeping it that way for long. Doing it this way meant that there was only 1 point of failure between me and a leak and a massive water bill and still dry lawn.

I had been looking into projects to do with Raspberry Pi microcomputers for a while and had previously stumbled on OpenSprinker. At the time I didn’t have a compelling case to buy another Pi, and expansion board and set it up.

This was now my chance. I was going to need to buy a new controller anyway, and if I wanted anything other than a cheap, basic, dumb replacement I was going to be up for at least $300.

OpenSprinkler here we come! Within a week of ordering, I had a new Raspberry Pi 3B+, an OpenSprinker Pi expansion board and a new 32GB micro SD card.

The whole process was very simple, quick and well explained from both Raspberry Pi for installing Raspbian, and OpenSprinkler for installing and setting up their board and software.

Once that was done inside it was time to take the Pi outside to the control box and swap the existing wiring over from the old controller to the Pi.

OpenSprinkler Pi uses the existing 24V AC power supply from the old controller. Then the common wire and all the individual zones wire in to the bottom of the unit.

This was the moment of truth. I took my phone out, loaded the web interface for OpenSprinker and started a zone for 10 seconds. Instantly the solenoids opened and the water started to flow! Perfect first time!

I ripped the guts out of the old controller, mounted the OpenSprinkler Pi into the weather proof enclosure and shut the door. You wouldn’t know the difference. Just how I like it and very high on the WAF (Wife Acceptance Factor).

I can now test and flush out sprinklers without having to run around the house to get to the controller. I can make sure my programs are running from anywhere in the world, see the history of when they’ve run and turn them off for winter without ever needing to go down the side of the house.

With a bit more research, I can even get it looking at local weather to either water more if it’s been hot, or skip a program if there has recently been rain.

Just another gadget in my ever growing list of conveniences in our house (up to over 30 network connected devices including TVs, smart speakers, smart lights, smart power points, laptops, phones, tablets, computers, NAS, security cameras… the list goes on.

Leave a Reply

Your email address will not be published.