FireBeetle ESP8266 IoT Microcontroller (Supports Wi-Fi)

DFRobot FireBeetle is a series of low-power-consumption development hardware designed for Internet of Things (IoT). Firebeetle ESP8266 is a development board integrated with IoT WiFi, TCP/IP, 32-bit MCU, 10-bit ADC, and multiple interfaces such as HSPI, UART, PWM, I2C, and I2S. In DTIM10, the full power consumption to maintain a WiFi connection reached 1.2mW. Equipped with 16MB outer SPI flash memory, ESP8266 is available for programs and firmware storage.
Compatible with Arduino programming enables Firebeetle ESP8266 to lower the barrier of programming. The operator can implement Arduino programming codes directly onto ESP8266 to reduce the difficulty of operating and increase the stability of the esp8266 board.

Tech Note 072 - ESP8266 and MAX30100 blood oximetry and heart-rate sensor display

NOTE: There still remain some bugs to be detected and fixed by developers. In some cases, some peripherals may not work perfectly by embedding Arduino sample codes in ESP8266.  Much more functions implemented in Arduino are still under development and improvement. An alternative way is to change development tools such as RTOS and MicroPython towards a more operating-friendly experience in some conditions.