What to do once you have a sprinkler system installed on your property: buy a sprinkler control system or make your own? The latter, obviously.
[danaman] was determined to hack together a cheap, IoT-enabled system but it wasn’t easy — taking the better part of a year to get working. Instead of starting right from scratch, he used the open-source Sustainable Irrigation Platform(SIP) control software — a Python sprinkler scheduler with some features [danman] was looking for(eg: it won’t activate if there’s rain in the forecast). Since he wasn’t running it with a Raspberry Pi as recommended, [danman] wrote a Python plugin that runs on his home server as a daemon which listens to TCP port 20000 for connections and then updates the relevant relays. Ok, software done; on to the relay controller box!
[danman]’s sprinkler system has four 12V AC valves that need wrangling, and no data cables, necessitating the wireless setup. Initially, his control box contained a 240V AC to 12V AC 50VA transformer to power the valves, and a 240 AC to 5V DC power supply for the USB relay board and WiFi router. Once hooked up outside however, the router proved incapable of a reliable connection. [danman] ordered in and made a second attempt with an ESP8266 — writing a program in LUA to connect to the SIP scheduler, but now the relay’s serial connection was the unreliable link. Frustration!
Opting for a more comprehensive solution, [danman] picked up a LinkNode R4 — a relay controller with integrated ESP8266 and controlled directly by the ESP’s GPIO pins — and reused his code from attempt number two, resulting in a smashing success!
[danman]’s code is available in his blog post you’ve been pondering a system like this for your own property. That is, unless you’re wanting something with a little more firepower.