The ESP8266 is a low-cost Wi-Fi chip with full TCP/IP stack and microcontroller capability produced by Shanghai-based Chinese manufacturer, Espressif Systems. The chip first came to the attention of western makers in 2014 when Espressif released a SDK that allowed the chip to be programmed, removing the need for a separate microcontroller. Thanks to the Arduino-compatible firmware for the ESP8266 which makes accessing low level WiFi functionality easy.
The cnlohr video show you can use ESPthernet to turn an ESP8266 into a remote Wireshark wifi sniffing station. So, the ESP is essentially running as a monitor mode wifi adapter over ethernet.
cnlohr has also developed the ESP8266 Ethernet driver. It only uses two pins on the ESP, the I2S pins, but does provide Ethernet which will prove useful for further experimenting. So to get started here is your shopping list:
- ESP8266 Serial Wi-Fi Transceiver Module $6
- Serial TTL to USB cable for programming $4
- A line driver like the ILS3371 and ethernet magnetics and terminator (optional).
- RJ45 jack.