Automation

A smart garden irrigation system on Home Assistant joins three parts: a Wi-Fi sprinkler controller, a rain sensor, and automations. The automations cancel or adjust watering based on rainfall, soil moisture, and the forecast. With the WiseWater integration and the native scheduler in Home Assistant 2025.12, this setup now beats pricey cloud-bound irrigation systems. Here is how to build one from scratch.

Why DIY Smart Irrigation Beats the Commercial Options

Commercial smart sprinkler controllers like Rachio , Orbit B-hyve , and RainBird Wi-Fi run $100 to $200. Their “smart” features all need a cloud link and often a paid plan. That includes weather skip logic, seasonal tweaks, and soil type awareness. If the vendor shuts down its servers (remember Wink ?), those features revert to dumb timer-only watering. You’re left with an overpriced relay board.

You can wire any microcontroller into Home Assistant over MQTT . Publish sensor data to discovery topics and subscribe to command topics. You get full firmware control without ESPHome’s abstraction layer. The trick works on any chip: ESP32, RP2040, STM32, or a Raspberry Pi Pico W. It’s the right pick when your device needs custom protocols, bare-metal timing, or firmware features ESPHome can’t reach.

This post covers when raw MQTT makes sense, the discovery protocol that auto-registers devices, firmware examples on the ESP32 and RP2040, two-way control patterns, and security hardening.

Property-based testing with Hypothesis lets you define what your code must do. One classic rule: “encode, then decode, and you get the same input back.” Hypothesis then makes up hundreds of random inputs and hunts for cases that break the rule. You don’t write test cases by hand. You sketch the shape of valid inputs. The tool finds the off-by-one bugs, the odd Unicode strings, and the edge cases hiding in your code.

Alembic is the standard migration tool for SQLAlchemy projects. You run alembic init, point it at your SQLAlchemy models, and use alembic revision --autogenerate to produce migration scripts. Alembic then applies those scripts in order with alembic upgrade head. You get repeatable, reviewable schema changes that work the same way everywhere your app runs. The latest stable release is Alembic 1.18.4. It supports SQLAlchemy 2.0 (now at 2.0.48) and its modern typed APIs.

Systemd timers should replace cron for nearly every scheduled task on modern Linux. They log to the journal, manage dependencies, and add random delays to avoid resource stampedes. They also catch up on runs missed during a reboot. The one reason to keep cron is legacy support on minimal systems without systemd. If your distro shipped in the last decade, you have everything to switch.

This guide covers the real problems with cron. It explains how systemd timers work and migrates several cron jobs step by step. It also covers the sandboxing and resource controls that make timers a better fit for production.

Gatus is a single-binary monitoring tool that probes your services and shows a public status page at a URL you control. You define every check in one YAML file. So your whole setup can live in Git next to the rest of your stack. There is no need for a database, no web UI to click through, and no per-monitor pricing. If you self-host a blog, a Gitea instance , a Home Assistant server, or a mail relay, Gatus gives you a simple way to know when something breaks.