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Comment by tekstar | Hacker News Reader

Can you explain this more? I've been getting into home automation and my wife would like programmable irrigation for when we're not at home. Did you interface with existing wifi valves or are you doing the circuit yourself?

I recently got rtlsdr to read my water meter so I can detect leaks, which is pretty cool

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What the OP did was build a simple irrigation controller for an existing irrigation system. Most irrigation systems use electronic solenoid valves that open when very low current 24 VAC power is applied to the two terminals.

Take a look at the Spec for a valve from Rainbird:

https://www.rainbird.com/sites/default/files/media/documents...

Electrical Specifications:

• Power: 24 VAC 50/60 Hz (cycles/second) GBS25 Solenoid

• Inrush Current: 0.41 A (9.84 VA)

• Holding Current: 0.20 A (4.80 VA) at 60 Hz, 0.23 A (5.40 VA) at 50 Hz

If you have a sprinkler system, you can replace the on/off valve with a solenoid valve and then you're able to control the system electronically using a 24 VAC power supply and a switch. The OP replaced the switch with a relay, which is a switch that can be actuated by the lower voltage from something like a microcontroller.

12v valves off Amazon. Don't get the cheap plastic ones. Get the brass versions

as long as you don't run several at once, can power from old wall wart with a few amps rating. I'm using a meanwell PSU so I can power a few other things - IR lights mostly

With existing WiFi valves, there would likely be no need for ESPHome.

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