IoT
Building a Smart Irrigation System with ESP32: System Architecture
An ESP32 irrigation controller combines sensing, decision logic, a protected valve driver and optional Home Assistant integration into one testable system.
Start with the control loop
The basic loop is straightforward: measure soil conditions, evaluate a defined rule, control a valve through a suitable driver, and expose state for monitoring. The engineering work is in making each boundary explicit and testable.
ITHutir's current Smart Irrigation Starter Pack is still a draft project, so this article describes the architecture rather than claiming a completed or production-tested build.
Hardware boundaries
The planned architecture uses an ESP32, a capacitive soil-moisture sensor, a DS18B20 temperature sensor, a normally closed solenoid valve, a valve driver and a gravity-fed water source. Exact component selections remain subject to the project's BOM validation.
The normally closed concept provides a useful default: loss of control power should not intentionally hold the valve open. The real installation still needs verification of valve voltage, driver sizing, protection, plumbing and supply behavior.
Software and Home Assistant
The ESP32 can own sensor acquisition and safe actuator logic while MQTT carries state and commands to Home Assistant. Home Assistant can then provide moisture display, valve status, manual control and higher-level automation.
Automation thresholds should be calibrated from real sensor and growing conditions rather than copied from an arbitrary example. The project should move from draft only after its BOM, wiring and behavior are validated with the actual hardware.