P14: Full-Stack IoT Access Control & Telemetry (ESP32 C++ + MQTT + BLE + Android Kotlin)

End-to-end IoT smart access control and telemetry system combining embedded ESP32 firmware in C++ (Wi-Fi, MQTT pub/sub telemetry, Bluetooth Low Energy provisioning, non-blocking state machine, hardware watchdog) with a native Android mobile app in Kotlin for real-time control and diagnostics. GitHub: https://github.com/r-menegueli/iot-esp32-mqtt-ble-android