OpenSprinkler 4 (OS 4) – Smart Irrigation Controller with ESP32

 New! Pre-order now – the OpenSprinkler 4 AC is available from 16/10/2026. Pre-orders will be shipped in the order they are received starting on this date.

 Version comparison: Which OpenSprinkler version is the right one? → To the large comparison table (Original vs. Shop vs. Pro)

New: OpenSprinkler 4 is here – the first OpenSprinkler generation with ESP32. Click here for the manufacturer's announcement.

OpenSprinkler is a open-source, web-based, smart irrigation controller for lawn and plant watering, drip irrigation, agriculture, greenhouses, and hydroponics.

The OpenSprinkler 4 looks identical to the OpenSprinkler 3.4 from the outside: same case, same ports. Inside, a new ESP32-C6 operates with a faster processor, significantly more RAM and flash memory, Wi-Fi 6, and USB-C. Existing Zone Expanders, the Sensor Expander, and the Ethernet module remain compatible.

How does it work? This is how it works!

Do you also need housings and accessories? Then click here!

What's new with OpenSprinkler 4

• ESP32-C6 instead of ESP8266: RISC-V processor at 160 MHz, 512 KB RAM, and 8 MB Flash. This provides headroom for future firmware features.
• Wi-Fi 6 (802.11ax) with WPA3 on the 2.4 GHz band, for better compatibility with modern routers and mesh systems.
• Enhanced security: Hardware-accelerated encryption as a foundation for secure network connections.
• Four built-in sensor ports (SN1–SN4): for rain sensors, soil moisture switches, flow meters, or program switches. The hardware also supports analog sensors (0–3.3 V) on each port; this feature will be added in the next firmware update.
• USB-C on board: Firmware recovery and diagnostics directly via PC, without an additional programming adapter.
• Ready for Matter, Thread, and Zigbee: The ESP32-C6 includes an 802.15.4 radio module. Firmware support has been announced by the manufacturer for future releases; it is not yet included at launch.
• Firmware update with a single click: The device automatically finds the right firmware, verifies it, and installs it.
• Accessories remain compatible: Zone expanders (v3), Sensor Expander, and the W5500 Ethernet Module.

Features

• Time-controlled switching of 24 VAC solenoid valves
• Free app for Android and iOS, web interface for access from PC
• Weather-based irrigation: runtimes are automatically adjusted based on weather data (Internet connection required)
• 8 zones in the base unit, expandable up to 72 zones with Zone Expanders (16 zones each)
• Up to 40 programs, sequential and parallel operation, station grouping for valves running concurrently
• Up to four master valves or pump relays
• Overcurrent and undercurrent detection on valve outputs
• Remote access via OpenThings Cloud (OTC), without any port sharing
• MQTT, email notifications and IFTTT
• Switch radio-controlled sockets (433 MHz) with the additional product RFToy
• OLED display and three buttons for operation directly on the device

You can find out more in the FAQ.

Try the interface? Here is the demo: demo.OpenSprinkler.com (Password “opendoor”)

Options

The OpenSprinkler 4 is available in one version (AC, 24 V alternating voltage). You can choose two options:

• Standard power supply: Plug-in power supply 24VAC / 1.5A. Without this option you will need your own 24VAC power supply.
• Ethernet network adapter: W5500 module (10/100 Mbit) with ribbon cable for connection via network cable. WiFi is always built in; When setting up, you choose between WLAN and LAN.

OpenSprinkler 4 and 3.4 in comparison

Do you need DC voltage or latching valves? The OpenSprinkler 4 is currently only available as an AC model. For 12 VDC valves, battery or solar operation, and for latching valves, you can find suitable devices with the OpenSprinkler 3.4 / 3.3 and the OpenSprinkler Pro.

The right power supply

Calculate the power requirement using the following rule of thumb. To do this, you need to know the current consumption of your solenoid valves.

OpenSprinkler itself requires approximately 0.1 A. A Rain Bird solenoid valve consumes a maximum of about 0.3 A.

With 4 simultaneously open solenoid valves, the inrush current is 4 × 0.3 A + 0.1 A = 1.3 A; the next larger power supply with 1.5 A is suitable.
If you only operate one or two solenoid valves simultaneously, it is 2 × 0.3 A + 0.1 A = 0.7 A; a 1 A power supply is sufficient. This also applies if you have 20 solenoid valves connected, but only open 2 at the same time.
Note: This is only an example calculation. Please observe the technical data provided by the valve manufacturer.

Other compatible power supplies: Plug-in power supply AC and AC DIN rail power supplies.

Never connect more than ONE solenoid valve to ONE OpenSprinkler output. OpenSprinkler can switch multiple outputs simultaneously, so there is no need to group valves together. One output delivers a maximum of 1 A. If that is not enough, switch the load via a relay.

Scope of delivery

• OpenSprinkler 4 (AC) in a plastic housing, with removable screw terminals
• Screw terminal to DC barrel jack adapter for power supplies with bare wire ends
• Standard power supply 24 VAC / 1.5 A (only with option "Standard power supply")
• Ethernet module W5500 with ribbon cable (only with option "Ethernet network adapter")
• German Quick Start Guide

Notes

• The OpenSprinkler is not waterproof. For outdoor installation, we recommend the IP65 housing.
• Wi-Fi only in the 2.4 GHz band; 5 GHz is not supported.
• When operating with the Ethernet module, Power over Ethernet (PoE) must be disabled on the network port.
• The USB-C port is used for firmware recovery and diagnostics. A 24 VAC power supply is always required to operate the solenoid valves.
• Product from the USA; delivery time is longer if not in stock.

System requirements

German manual, quick start guide, and circuit diagram: Manual and Downloads

Downloads

• OpenSprinkler 4 – Quick Start Guide (PDF, German)
• User manual firmware 2.2.1(6) (PDF, German)
• All manuals and downloads

Notes

• The enhanced OpenSprinklerShop firmware is NOT compatible with the OpenSprinkler 4 – we are working on it