A Complete MQTT+ESP32 Sensor Tutorial

Building an MQTT enabled door sensor using ESP32 and PlatformIO

This article is motivated by my previous article on ESPHome. Previously, we built a door sensor using ESPHome library. However, using an off-the-shelf platform grants us with little to no flexibility when it comes to micro-optimizations. Having said that, I noted the best implementation consumed over 1mA and took nearly 2 seconds to respond (Even after using MQTT, ESPHome API is known to be slower with HomeAssistant).