Hello! Sorry for the late replay but this did not help unfortunately. Do you have any other suggestions? Regards

Sure! I use the following components: [*] AMS1117: http://www.advanced-monolithic.com/pdf/ds1117.pdf [*] AZDelivery ESP32-WROOM-32 with CP2102: https://cdn.shopify.com/s/files/1/1509/1638/files/ESP_-_32_NodeMCU_Developmentboard_Datenblatt_AZ-Delivery_Vertriebs_GmbH_10f68f6c-a9bb-49c6-a825-0797944173...

Hello! I want to build my own weather station that periodically transmits temperature every hour using MQTT via WiFi. Everything works fine when powering the ESP32 via USB or via 5V using a YW Robot Power MB V2 - however, when I try to power it using 4xAA with a DC Buck Modul AMS1117 or a 3,3V input...