Mike Rankin created this board with a tiny OLED display controlled by an ESP8266:

MicroUSB powered ESP8266 OLED Boar

I created this design as a challenge to make a design under 1″ x 1″ in size.

The hardware is an ESP-01 ESP8266 Wifi module, linear power supply, microUSB connector and a few oled display parts.

The design files and source code are available on GitHub:

ESP8266_OLED

Here is a video of the assembly and operation:

miker has shared the board on OSH Park:

ESP8266 OLED Board Rev3