Automatic watering system using Gardena 1197 + OpenHab + Pilight

I was tired of having the repetitiveness of watering my garden every day so I wanted a solution to manage the garden watering. It was not as simple as just using one circuit because my garden is spread out, so different areas need different times and water pressure is a problem. I also did not want to dig my garden up to lay down new water pipes, so I wanted to be able to use my existing garden hose's.

The solution cost was to use Gardena automatic water distributor along with an single electronic valve from Hunter. This keeps the electrics simple and the connections plug and play. The control was done with openhab running on a raspberry pi, which triggered the valve via a remote 433mhz switch. You could obviously use a valve per circuit, but this requires another bridge to the PI and I had the 433Mhz already set up with pilight. As it is below you can also switch the valve with an electric pump, which I sometimes do when I have collected enough rain water.

Parts list:
1.) Remote switch - 25 Euro - Although I had this already
2.) Gardena automatic water distributer - 55 Euro
3.) 24 V AC Transformer - 12 Euro
4.) Hunter PGV-100 valve - 16 Euro - basically cheaper than Gardena version
5.) Raspberry PI - 40 Euro - although had this already as well
6.) Aurel 433Mhz transmitter
7.) Various garden houses to different sections of the garden, 4 circuits in use, but up to 6 can be used

View of the switch, the transformer and hunter valve

Garden Distributor

The Gardena distributor works quite simply by switching to the next circuit when there is no water pressure for a certain period of time (I was using about 10 seconds). So with a on-off-on-etc pattern you can control up to 6 circuits with different time periods if you want.

View of control panel in Openhab basic UI

Pilight needs to be installed and the pilight binding needs to be setup inside openhab

addons.cfg:
    pilight:kaku.host=192.168.2.168
    pilight:kaku.port=5000
    pilight:kaku.delay=1000

Pilight devices:

     "devices": {

                "desklamp": {

                        "protocol": [ "kaku_switch" ],

                        "id": [{

                                "id": 15831690,

                                "unit": 1

                        }],

                        "state": "off"              

        },

Items file:
Switch  KakuDeskLamp    "Water"               {pilight="kaku#desklamp"}
Switch  WaterTest    "Water Test"
Switch  StartProgram    "Start Program"
Switch  KakuSmallBathFan    "Small bath fan"               {pilight="kaku#smallbathfan"}
Number      Irrigation_LawnMins     "Lawn Sprinkler [%d mins]"  <water>         (Irrigation)
Number      Irrigation_Pause     "Break [%d mins]"  <water>         (Irrigation)
Number      Irrigation_Multiplier     "Multiplier [%d mins]"  <water>         (Irrigation)
Number      Irrigation_Circuits     "Circuits [%d]"  <water>         (Irrigation)
Number      Irrigation_ActiveCircuit     "Circuits [%d]"  <water>         (Irrigation)

Number      Irrigation_Repeats     "Repeats [%d]"  <water>         (Irrigation)

Openhab rules:
    rule "Enabling irrigation"
    when
    Item StartProgram changed from OFF to ON or
    Time cron "0 45 7 1/1 * ? *"
    then
      var i = 0
      var Number lawnMins = Irrigation_LawnMins.state as DecimalType
      var Number pause = Irrigation_Pause.state as DecimalType
      var Number Multiplier = Irrigation_Multiplier.state as DecimalType
      var Number Circuits = Irrigation_Circuits.state as DecimalType
      var Number Repeats = Irrigation_Repeats.state as DecimalType
      lawnMins = lawnMins*1000
      if (Multiplier != 0)
      {
        lawnMins = lawnMins*Multiplier
      }
      logInfo("Irrigation", "Circuits " + Circuits + " multiplier " + Multiplier)
      while ((i=i+1) < Circuits+1) {
        var j = 0
        while ((j=j+1) < Repeats+1) {
                logInfo("Irrigation", "Repeat " + j)
                sendCommand(KakuDeskLamp, ON)
                Thread::sleep(100)
        }
    
        logInfo("Irrigation", i + " lawnMins " + lawnMins)
        sendCommand(Irrigation_ActiveCircuit, i)
        Thread::sleep(lawnMins.intValue) //*lawnMins)
        j = 0
        while ((j=j+1) < Repeats+20) {
                logInfo("Irrigation", "Repeat " + j)
                sendCommand(KakuDeskLamp, OFF)
                Thread::sleep(100)
        }
   
        sendCommand(Irrigation_ActiveCircuit, 0)
    
        Thread::sleep(1000*pause.intValue)
      }
      sendCommand(StartProgram, OFF)
    end