ESP8266 is a chinese microcontroller that I discovered few weeks ago thanks to @jordibinefa, and their highlights are that the ESP8266 is a LUA programmed, ultra low cost, fast, 32 bits and WiFi enabled microcontroller.
The specs of the ESP8266:
- 32-bit RISC CPU: Tensilica Xtensa LX106 running at 80 MHz
- 64 KiB of instruction RAM, 96 KiB of data RAM
- External QSPI flash – 512 KiB to 4 MiB
- IEEE 802.11 b/g/n Wi-Fi
- 16 GPIO pins
- SPI, I²C,
- I²S interfaces with DMA (sharing pins with GPIO)
- UART on dedicated pins, plus a transmit-only UART can be enabled on GPIO2
- 1 10-bit ADC
After some days playing with it, I must say that is a great Arduino alternative, especially if you need a lot of raw power and on-borad WiFi capabilities.
The most common board that uses the ESP8266 is the ESP-12, and you can also buy the ES8266 with a programable USB board (like nodeMCU) to work like an Arduino.