Wemos TTGO ESP8266 with 0.91" OLED

I have been looking for an ESP8266 board that has voltage converters like a NodeMCU but is much smaller and space saving. Background is my current project “fridge-kola” to control a wine fridge as an IoT device via my smart home and to read out its state. The TTGO board with integrated OLED display is perfect for my requirements. It has exactly the right size to be placed in the handle of the fridge and offers all necessary interfaces to read my NTC temperature sensor, control the cooling circuit control and the interior lighting. By the way, the board also works with ESPHome without any problems.

Specifications⌗

Front View⌗

In addition to the OLED display, two hardware buttons for resetting and flashing the ESP8266 and the micro-USB port are located on the front.

Back View⌗

On the backside there is - unshielded - the ESP8266 chip and a connector for a battery. There are reports about poor WIFI performance in relevant Internet communities. I assume that this is due to the positioning of the antenna behind the flex cable, as well as the lack of shielding of the microcontroller.

Board Layout⌗

The following pins are occupied by the display:

Code Example⌗

// This example of the Adafruit_SSD1306 library worked for me.
// I only modified initialising Wire with the appropriate I2C pins.

...
#define OLED_SDA 2
#define OLED_SCL 14
#define OLED_RST 4
...
Wire.begin( OLED_SDA, OLED_SCL);
...

Interface Pin Function of OLED (WEO012832)⌗