This App demonstrate Nucleo_F411RE connecting to ESP01 (ESP8266) through UART and get enviroment data by BME280 over I2C bus. the unit send the data to ThingSpeak cloud and persent it by three chatrs.
https://easyeda.com/editor#id=664e8544225641feb8eb29158b23b3a9
Need to add float option in linker on project settings with sprintf() function.