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Ingredient

Solenoid valve

Also known as: irrigation solenoid, 12V solenoid valve, 24V AC valve

Electromagnetically-actuated valve — a coil pulls a plunger that opens (or closes) a fluid passage. The standard ingredient for digital irrigation: drip lines, raised-bed manifolds, fertigation injectors. Two main classes: low-voltage 12V DC (battery- and solar-friendly, hobbyist) and 24V AC (the irrigation-industry standard, used by commercial controllers). Typical hobbyist plastic-body valves $5–15; brass-body 24VAC valves $15–40. Pair with a relay or MOSFET driver — solenoids draw too much current to drive directly from an MCU pin.

Inputs / outputs

  • Power: 12V DC (hobbyist) or 24V AC (commercial), ~250–500 mA inrush, 100–200 mA holding
  • Flow: 1–30 GPM typical depending on body size and pressure
  • Pressure: check rated PSI range — most hobbyist plastic-body valves rated to ~145 PSI
  • Orifice: normally-closed (NC) is default; normally-open (NO) variants exist

Solves / unlocks

  • Zoned drip-irrigation control (one valve per bed or row)
  • Fertigation injection (dose nutrient stock into mainline at controlled intervals)
  • Greenhouse misting / fogging schedules
  • Aquaponic / hydroponic top-off (refill reservoir from city water on level switch)
  • Timed evening-only irrigation (avoid wet-leaf overnight disease pressure)

Constraints

  • Driver required — never drive a solenoid directly from an MCU pin; use a relay module, MOSFET driver, or dedicated solenoid-driver board.
  • Flyback diode — DC solenoids generate inductive kick when de-energized; the driver must include a flyback diode (relay modules have this; bare MOSFET circuits need one added).
  • Holding current burns power continuously while the valve is open — for solar-powered systems, prefer latching valves (mechanically hold position; only need a brief pulse to switch).
  • Water-hammer on fast-closing valves can damage plumbing; install pressure relief or use slow-close valves on long runs.

Source

  • Hobbyist plastic 12V: Adafruit #997, Sparkfun, generic AliExpress
  • Commercial 24VAC: Rain Bird, Hunter, Toro irrigation valves
  • Latching solenoid (battery-friendly): Hunter SVB-100

See also

Auto-generated from this entry’s typed relations: frontmatter, grouped by relation type so the editorial signal isn’t flattened.

  • Member of: [[ingredient]]
  • Combines with: [[arduino-uno]] · [[esp32]] · [[capacitive-soil-moisture-sensor]] · [[home-assistant]]

What links here, and how

Inbound connections from across the wiki, grouped by lens and by relationship. These appear automatically — every entity page declares what it links to, and that data populates here on the targets.

Practical

combines with

  • Arduino Uno via relay or MOSFET driver; digital irrigation gating
  • Capacitive soil moisture sensor the canonical closed-loop: read moisture → open valve → measure → close
  • ESPHome ESPHome relay / GPIO output components turn a valve manifold into a Home Assistant device
  • FarmBot Genesis the watering tool dispenses through a solenoid; programmable per-plant volume
  • Home Assistant ESPHome + valve manifold = Home Assistant device for zoned irrigation

contains

combines

7 inbound links · 5 outbound