Single-coil (two-wire). These are single coil, and require reversing polarity to change the latch. This is complex.
Dual coil ("three-wire"). These are easier to deal with electronically. They do not look as well sealed as the single coil valces.
- DN15 (13mm) DC-12-24V switching ball valve brass NZ$25.49
- DN20 (13mm) DC-12-24V switching ball valve brass NZ$29.71
✅ Dual coil IP65
- 1/2" (13mm) IP65 Waterproof Motorized Ball Valve 3-Wire 2 Control Brass Electric Ball Valve Big Torque Metal Motor - 12V DC, CR02 $NZ20.18
- 3/4" (19mm) IP65 Waterproof Motorized Ball Valve 3-Wire 2 Control Brass Electric Ball Valve Big Torque Metal Motor - 12V DC, CR02 $NZ23.17
Power draw: 6W for 5-15 seconds during valve state transition.
The manifold takes input from the 20mm alkathene, into a 25mm PVC manifold. This has outlets that go to the solenoids. On the other side of the solenoids are 19mm distribution pipes for each zone.
- 25 mm PVC pipe (closer to 20 mm MDPE flow capacity)
- 25mm → 20mm MDPE adaptor at the inlet
- ¾" BSP threaded tees or bushings
- Screw valves directly
Assembled, it looks something like this:
or like this:
It needs a master cut off valve in front of it.
- Male BSP 3/4" -> 19mm barb brass NZ$2.78
- 1/2" 3/4" Water Flow Sensor Switch With Temperature Detection For Turbine Liquid Sensor Copper Shell Hall Flow Meters NZ$1.76 | NZ$3.78
Flow sensor to enable partial opening and detect stuck open.
I2C expansion board is needed to get enough pins to control the solenoids and read the rain sensor:
- MCP23017-E/SS I2C IIC Expander Board Module I2C to 16IO IIC Input/Output Expansion Board MCP23017 3.0V-5.5V NZ$1.76 each (get a bunch for redundancy/expansion/spares)