This repository contains the ESP-Drone firmware, an open-source flight control system for quadcopters based on Espressif ESP32/ESP32-S2/ESP32-S3 microcontrollers. It is a port of the Bitcraze Crazyflie firmware (GPLv3) and is primarily designed for STEAM education. The system provides a complete drone control stack including sensor drivers (IMU, barometer, magnetometer, ToF range finders, optical flow), state estimation (complementary filter, extended Kalman filter), attitude/position controllers (PID, Mellinger, INDI), and communication via Wi-Fi (UDP, ESP-NOW) and CRTP protocol. It supports modular expansion 'decks' for additional hardware like flow sensors, thermal cameras, and localization systems (Lighthouse V1/V2, UWB TDoA). The firmware runs on FreeRTOS and uses ESP-IDF v5.0 as its development framework.