in this video I go over arduino code on how to send data from a SD card to MQTT. this sketch is designed for the Bee Data Logger which is a feature packed ESP32 data logger (not for tracking bees) but even if you do not have the bee data logger you may find bits of this code useful. Github for Bee Data Logger - https://github.com/strid3r21/Bee-Data-Logger Buy It Here - Tindie https://www.tindie.com/products/smartbee/esp32-data-logger-wrtc-sd/ or EU/UK here - Lectronz https://www.lectronz.com/products/esp32-data-logger The code example in this video can be found here - https://tinyurl.com/BDL-SD-2-MQTT