Learn how to build and install an ESP32-based mailbox sensor that integrates with Home Assistant, providing voice or push notifications when mail is delivered. Follow along with the step-by-step process, from selecting parts and assembling the device to configuring ESPHome and setting up Home Assistant entities, scripts, and automations. Discover how to create this cost-effective, hub-free solution for around $35, requiring only a WiFi signal at your mailbox location. Gain insights into disabling LEDs, conducting bench tests, and properly installing the sensor in your mailbox. Access additional resources, including a full parts list, wiring schematics, and code samples, to enhance your understanding and implementation of this DIY smart home project.