In a previous post I mentioned that I used an ESP8266 as a WiFi to serial console bridge. Having a secondary method to connect to a headless computer is a functionality that is very common when it comes to commercial servers. When working with servers and network equipment unexpected situations will make it necessary to have the means to continue managing, power cycling or even reinstalling software in the equipment remotely. The most complete solutions implement out-of-band management which provides access to the equipment via a dedicate communication medium. The WiFi to serial console bridge in this post falls under the in-band management classification. This is because it uses the same medium for management as the computer uses for normal communications, requires support on the part of the computer to work, and requires the computer to be powered on.

Basic tools and materials needed

Materials

To build this WiFi to serial console bridge you will need:

An ESP8266 board. I used an ESP-01 as it was the most easy to source at the time and one of the smaller modules available for this microcontroller.

Wire cutters

Wire strippers

Solder iron

Solder wire

4 wire connector set

3 x 10k ohm resistors

ODROID C2

An ESP8266 in an ESP-01 module configuration. Image from https://en.wikipedia.org/wiki/ESP8266

The ESP8266 is a low cost microcontroller with a full TCP/IP stack and wireless capabilities. It is manufactured by Espressif Systems and has become very popular.