Water leak sensors can prevent serious damage from leaking pipes, washing machines, dishwashers, boilers, and under-sink plumbing.With an ESP32 and a simple water leak probe, it is easy to build a low-cost, fast, and fully local leak detection system that…

A motion sensor that only turns lights on when it’s dark is one of the most useful smart home automations.By combining a PIR motion sensor with a simple LDR (light-dependent resistor) and an ESP32, it’s easy to build a local,…

Indoor air quality is not just about CO₂. Volatile organic compounds (VOCs) from cleaning products, furniture, paints, cooking, and people can significantly affect comfort and health. The SGP40 is a modern VOC sensor designed specifically for indoor air quality applications,…

Combining a PIR motion sensor with an LDR light sensor is one of the most flexible ways to create intelligent room automation.With this setup, lights can automatically turn on only when the room is dark and motion is detected —…

Indoor air quality (IAQ) is influenced not only by CO₂ and humidity, but also by volatile organic compounds (VOCs) such as cooking fumes, cleaning chemicals, paints, perfumes, and off-gassing from furniture.The SGP40 is a high-quality VOC sensor from Sensirion that…

Controlling a DC fan using PWM (Pulse Width Modulation) is an easy and cost-effective way to cool network cabinets, 3D printer enclosures, AV racks, routers, amplifiers, or any electronics that require temperature-activated airflow. This guide explains how to use an…

A reed switch is one of the simplest and most reliable ways to detect when a door or window opens. When combined with an ESP32, it becomes a fast, local, battery-free, and cloud-free door sensor that integrates perfectly with Home…

Monitoring indoor CO₂ levels is one of the most effective ways to track air quality, improve ventilation, and maintain a healthy indoor environment.The SCD30 and SCD41 are two of the best consumer-grade CO₂ sensors, offering accurate measurements and excellent long-term…

The ESP32 Bluetooth Proxy solves this problem by extending Home Assistant’s Bluetooth range using inexpensive ESP32 boards placed around the home. Bluetooth Low Energy (BLE) sensors such as the Xiaomi Mi Temperature, Inkbird, Switchbot, and many others are extremely popular…

Passive Infrared (PIR) motion sensors are one of the simplest and most effective ways to detect motion in a room. Combined with an ESP32, they provide extremely fast, local, cloud-free motion detection that integrates perfectly with Home Assistant. This guide…