First of all, read the article “STM32: use WiFiNINA with ESP32 WiFi Co-Processor”, where there are all the basics to understand this shield usage better.

For me, It’s very important the network connection and network limitation on STM32 It’s very tedious. Adafruit offers a solution, but I think that a shield It’s more usable.

So I design a shield to add WiFi to my STM32F1 blue-pill.

PCB

The PCB is quite simple, I also add an interface to update the firmware over esp32. Strangely, esp32-s seems to update better than esp32-wroom-32. Probably the thin wire adds noise to the serial transfer.

ESP32 S pinout low resolution

Here my selection of esp32 AliExpress ESP32 Dev Kit v1 - AliExpress selectable - AliExpress TTGO T-Display 1.14 ESP32 - AliExpress NodeMCU V3 V2 ESP8266 Lolin32 - AliExpress WeMos Lolin32 CP2104 CH340 - AliExpress ESP32-CAM programmer - AliExpress ESP32-CAM bundle - AliExpress ESP32-WROOM-32 - AliExpress ESP32-S

It’s crucial to select an stm32f1 of good quality. Some clone devices have trouble.

Here is the PCB drawing.

The result is this PCB. Here is the top view:

and here is the bottom.

At the top, you can see the pad to solder to select the CS pin of the WiFi module (refer to the article about Wifi coprocessor).